We provide laws of motion practice exercises, instructions, and a learning material that allows learners to study outside of the classroom. We focus on laws of motion skills mastery so, below you will get all questions that are also asking in the competition exam beside that classroom.
List of laws of motion Questions
| Question No | Questions | Class |
|---|---|---|
| 1 | The arrow with a pointed tip can move faster in air than that of with a blunt tip. A. True B. False c. Ambiguous D. Data insufficient |
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| 2 | If a man is walking, then the direction of friction is: A. opposite to direction of motion B. same as that of direction of motion. c. perpendicular to direction of motion. D. ( 45^{circ} ) to the direction of motion |
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| 3 | Match the following List I a. Static ( quad ) e. constant for a given pair of friction ( quad ) surfaces b. Limiting ( quad ) f. independent of area of contact friction c. Kinetic ( quad ) g. self adjusting friction d. Rolling ( quad ) h. has the least magnitude for a friction ( quad ) given normal reaction ( mathbf{A} cdot a rightarrow e ; b rightarrow f ; c rightarrow g ; d rightarrow h ) B ( cdot a rightarrow h ; b rightarrow f ; c rightarrow e ; d rightarrow g ) ( mathbf{c} cdot a rightarrow g ; b rightarrow e ; c rightarrow f ; d rightarrow h ) ( mathbf{D} cdot a rightarrow g ; b rightarrow h ; c rightarrow f ; d rightarrow e ) |
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| 4 | For the pulley system shown in Fig.6.317, each of the cables at ( A ) and ( B ) is given a velocity of ( 2 m s^{-1} ) in the direction of the arrow. Determine the upward velocity v of the load ( m ) A ( cdot 1.5 m s^{-} ) ( mathbf{B} cdot 3 m s^{-1} ) ( c cdot 63 s^{-1} ) D. ( 4.5 m s^{-} ) |
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| 5 | Distinguish between Inertia of motion and inertia of direction | 11 |
| 6 | Which of the following is/are true about force A. Force will always change the magnitude of velocity B. Force will always change the direction of velocity c. s.l unit of force is Newton D. All the above |
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| 7 | The catcher prepares to receive a pitch from the pitcher. As the ball reaches and makes contact with his glove, the catcher pulls his hand backward. This action reduces the impact of the ball on the catcher’s hand because: A. The energy absorbed by his hand is reduced B. The momentum of the pitch is reduced c. The time of impact is increased D. The time of impact is reduced E. The force exerted on his hand remains the same |
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| 8 | 2. A block of mass 2 kg rests on a rough inclined plane making an angle of 30° with the horizontal. The coefficient of static friction between the block and the plane is 0.7. The frictional force on the block is (IT JEE, 1982) a. 9.8 N b. 0.7 x 9.8 x(13) N c. 9.8 x(13)N d. 0.7 x 9.8 N |
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| 9 | An impulse is supplied to a moving object with the force at an angle of ( 120^{circ} ) with the velocity vector. The angle between the impulse vector and the change in momentum vector is A ( cdot 120^{circ} ) в. ( 0^{circ} ) ( c cdot 60^{0} ) D. ( 240^{circ} ) |
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| 10 | A uniform rule is pivoted at its mid point. A weight of ( 50 g f ) is suspended at one end of it. Where should a weight of ( 100 g f ) be suspended, to keep the rule horizontal? A. ( 10 mathrm{cm} ) from mid point B. ( 25 mathrm{cm} ) from mid point c. ( 20 mathrm{cm} ) from mid point D. ( 15 mathrm{cm} ) from mid point |
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| 11 | The casing of a rocket in flight burns up due to friction. At whose expense is the heat energy required for burning obtained? The rocket or the atmosphere |
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| 12 | An astronaut accidentally gets separated out of his small spaceship accelerating in inter stellar space at a constant rate ( 50 m s^{-2}, ) what is the acceleration of the astronaut the instant after he is outside the spaceship? (Assume that there are no nearby starts to extract gravitational force on him). |
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| 13 | A vehicle is moving with a speed ( v ) on a curved smooth road of width ( b ) and radius ( R ) For counteracting the centrifugal force on the vehicle, the difference in elevation required in between the outer and inner edges of the road is A ( cdot frac{v^{2} b}{R g} ) в. ( frac{v b}{R g} ) ( c ) ( D ) |
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| 14 | If a force of ( 200 N ) acts on a body. The momentum acquired is ( 100 k g m / s ) What is the period for which force acts on the body? A . ( 0.2 sec ) B. ( 0.5 mathrm{sec} ) c. ( 0.4 mathrm{sec} ) D. 0.25 sec |
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| 15 | A block of mass ( 1 mathrm{kg} ) is pressed against a wall by applying a horizontal force of 10N on the block. If the coefficient of friction between the block and the wall is ( 0.5, ) magnitude of the frictional force acting on the block is ( mathbf{A} cdot 9.8 N ) B. ( 0.98 N ) c. ( 1.96 N ) ( D .5 N ) |
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| 16 | Assertion: A quick collision between two bodies is more violent than a slow collision; even when the initial and final velocities are identical. Reason: The momentum is greater in first case A. If both assertion and reason are true but the reason is the correct explanation of assertion. B. If both assertion and reason are true but the reason is not the correct explanation of assertion c. If assertion is true but reason is false D. If both the assertion and reason are false. E . If reason is true but assertion is false |
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| 17 | 41. Two discs, each having mass m, are attached rigidly to the ends of a vertical spring. One of the discs rests on a horizontal surface and the other produces a compression Xo on the spring when it is in equilibrium. How much further must the spring be compressed so that when the force causing compression is removed, the extension of the spring will be able to lift the lower disc off the table? Fig. 8.235 a. xo b. 2×0 c. 3×0 d. 1.5xo 1 1 1 |
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| 18 | a 20 DO 16. Blocks A and C start from rest and move to the right acceleration ay = 12t ms and ac = 3 ms. Here tie: seconds. The time when block B again comes to rest is Fig. 6.305 a. 2s b. 1 s c . 3/2 s d. 1/2 s |
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| 19 | A block of mass ( 2 k g ) slides down the face of a smooth ( 45^{circ} ) wedge of mass ( 9 k g ) as shown in the figure. The wedge is placed on a frictionless horizontal surface. Determine the acceleration of the wedge. ( A cdot 2 m / s^{2} ) B. ( frac{11}{sqrt{2}} mathrm{m} / mathrm{s}^{2} ) ( mathrm{c} cdot 1 mathrm{m} / mathrm{s}^{2} ) D. None of these |
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| 20 | A flat car is pulled with a constant acceleration ( 2 m / s^{2} . ) The mass of the block is ( 50 mathrm{kg} ). There is friction between the flat car surface and the block. The wheels of the car are rolling without slipping. Then This question has multiple correct options A. tension in the string is ( 350 mathrm{N} ) B. frictional force is 150 N C. acceleration of the block is ( 4 m / s^{2} ) D. acceleration of center of the weel is ( 1 mathrm{m} / mathrm{s}^{2} ) |
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| 21 | A vehicle of mass ( m ) is driven along an un-banked curved path of radius of curvature ( r ) with a speed ( v ). If ( mu ) is necessary minimum coefficient of friction between tyres of vehicle and road so that the vehicle does not skid, then: This question has multiple correct options A ( cdot mu propto v^{2} ) B ( cdot mu propto frac{1}{v^{2}} ) c. ( mu propto r ) D. ( mu propto frac{1}{r} ) |
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| 22 | 980. Voo . m 2 12. An inclined plane makes an angle 30° with the horizontal. A groove (OA) of length 5 m cut in the plane makes an angle 30° with OX. A short smooth cylinder is free to slide down under the influence of gravity. The time taken by the cylinder to reach from A to O is (g = 10 ms) Cylinder ol 30° a. 45 Fig. 6.302 b. 2s c. 3s d. 1s |
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| 23 | A machine gun fires a bullet of mass ( 40 g ) with a velocity of ( 1200 m s^{-1} . ) The man holding it can exert a maximum force of ( 144 N ) on the gun. How many bullets can he fire per second at the most? A B. 3 ( c cdot 2 ) ( D ) |
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| 24 | Block A weight 4N and block weight 8N The coefficient of kinetic friction is 0.25 for all surfaces. Find the force ( F ) to slide ( mathrm{B} ) at a constant speed when ( (mathrm{a} 0 mathrm{A} ) rests on B and moves with it, (b) A is held at rest, and (c) A and B are connected by a light cord passing over a smooth pulley as shown in Fig., respectively. |
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| 25 | A person standing in a moving bus falls backwards when bus suddenly starts moving in forward direction. This happens due to | 11 |
| 26 | Example 7.4 Two blocks A and B of equal masses are placed on rough inclined plane as shown in Fig. 7.209. When and where will the two blocks come on Em the same line on the inclined plane if they are released simultaneously? Initially the block A is 2 m behind the block B. Coefficients of kinetic friction for the blocks A and B are 0.2 and 0.3, respectively (g = 10 ms-2). Fig. 7.209 |
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| 27 | Two particles of mass ( m ) each are tied at the ends of a light string of length ( 2 a ) The whole system is kept on a frictionless horizontal surface with the string held tight so that each mass is at a distance ( a ) from the center ( P ) (as shown in the figure). Now, the mid-point of the string is pulled vertically downwards with a small but constant force ( F ). As a result, the particles move towards each other on the surface. Find the magnitude of acceleration, when the separation between them becomes ( mathbf{2} boldsymbol{x} ) |
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| 28 | A number of discs, each of momentum Mkgm/s are striking a wall at the rate of ( n ) discs per minute. The force associated with these discs, in newtons, would be A. ( frac{M n}{60} ) в. ( 60 M n ) c. ( frac{M}{60 n} ) D. ( frac{n}{60 M} ) |
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| 29 | A ( 4- ) kilograms ball slides over horizontal friction less surface with velocity of meter per second ball strike the post and rebounds upward perpendicular to the initial direction with same speed. Calculate the change of momentum of the ball in initial direction. A. ( -4 mathrm{kg}, mathrm{m} / mathrm{s} ) B. – – 1 kg.m/s c. ( 0 mathrm{kg} . mathrm{m} / mathrm{s} ) D. ( 1 mathrm{kg} . mathrm{m} / mathrm{s} ) E . ( 4 mathrm{kg} . mathrm{m} / mathrm{s} ) |
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| 30 | An object mass ( m_{1} ) moving with speed collides with another object of mass ( boldsymbol{m}_{2} ) at rest and stick to it. Find the impulse imparted to the second object. |
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| 31 | A tunnel is dug along a chord of the earth at a perpendicular distance R/2 from the earth’s centre. The wall of the tunnel may be assumed to be frictionless. Find the force exerted by the wall on a particle of mass ( mathrm{m} ) when it is at a distance ( x ) from the centre of the tunnel. |
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| 32 | In which case of a moving body, force is not needed? A. To increase the speed of the body B. To decrease the momentum of the body c. To change the direction of motion D. To keep the body in uniform velocity |
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| 33 | Assertion It is difficult to move a bike with its breaks on Reason Sliding friction is greater than rolling friction. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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| 34 | Which force of friction which does not allow one body to slide upon another is called A. Kinetic friction B. Static friction c. Both D. none |
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| 35 | A force-time graph for the motion of a body is shown in figure. Change in linear momentum between 0 and 8 s is: A. zero B. 4 N-s ( c cdot 8 ) Ns D. None |
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| 36 | A block of mass’ ( m^{prime} ) is kept on the ground as shown in figure. Which of the following statements is/are correct of action-reaction force pair? This question has multiple correct options A. Normal force can never be a reactive force B. Weight of the body is not a part of action reaction pair c. Forces act on different bodies D. None of these |
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| 37 | Find the distance the rain drop has fallen in ( t=3 s: ) A. ( 12 mathrm{m} ) в. 22.5 m c. ( 2.5 mathrm{m} ) D. 7.2 ( m ) |
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| 38 | A cricketer catches a ball of mass ( 150 g ) in ( 0.1 s ) moving with speed ( 20 m / s ) then the experiences force of |
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| 39 | The acceleration of block ( mathrm{B} ) in the figure will be: ( mathbf{A} ) B. c. ( frac{2 M_{1} g}{left(M_{1}+4 M_{2}right)} ) D. ( frac{2 M_{1} g}{left(M_{1}+M_{2}right)} ) |
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| 40 | A small child tries to move a large rubber toy placed on the ground. The toy does not move but gets deformed under her pushing force ( (overrightarrow{boldsymbol{F}}) ) which is obliquely upward as shown. Then A ( cdot ) The resultant of the pushing force ( (vec{F}), ) weight of the toy, normal force by the ground on the toy and the frictional force is zero B. The normal force by the ground is equal and opposite to the weight of the toy C . The pushing force ( (vec{F}) ) of the child is balanced by the equal and opposite frictional force D. The pushing force ( (vec{F}) ) of the child is balanced by the total internal force in the toy generated due to deformation |
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| 41 | The force required just to move a body up an inclined plane is double the force required just to prevent the body sliding down. If the coefficient of friction is 0.25 the angle of inclination of the plane is A ( cdot 36.8^{circ} ) B . ( 45^{circ} ) ( c cdot 30^{circ} ) D. ( 42.6^{circ} ) |
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| 42 | The limiting value of static friction is A. Equal to the dynamic friction B. Always less than the dynamic friction c. Always greater than dynamic friction D. Less than the rolling friction |
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| 43 | Hence, acceleration of C = 2.5 ms Illustration 7.32 In the situation shown in Fig. 7.117, a. What minimum force F will make any part or wi system move? b. Find the acceleration of two tion of two 4kg Mi = 0.1 blocks and value of friction at the two surfaces if F=6 N. Fig. 7.117 | 2 kg H2=0.2 |
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| 44 | A particle of mass ( m ) is made to move with uniform speed ( v_{0} ) along the perimeter of a regular hexagon, inscribed in a circle of radius R. The magnitude of impulse applied at each corner of the hexagon is : A ( cdot 2 m v_{0} sin frac{pi}{6} ) В. ( m v_{0} sin frac{pi}{6} ) c. ( _{m v_{0} sin frac{pi}{3}} ) D. ( 2 m v_{0} sin frac{pi}{3} ) |
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| 45 | Two masses are balanced on the scale pictured above. If the bar connecting the two masses is horizontal and massless, what is the weight of mass ( m ) in terms of M? |
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| 46 | A ball is released from height along the slope and move along a circular track of radius ( R ) without falling vertically downwards Show that ( h=frac{5}{2} R ) |
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| 47 | A block of mass 5 kg is lying on a rough horizontal surface. The coefficient of static and kinetic friction are 0.3 and 0.1 and ( g=10 m s^{-2} . ) The frictional force on the block is? A . ( 25 mathrm{N} ) B. 15N c. 10 N D. zero |
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| 48 | An iron block of sides ( 5 mathrm{cm} times 8 mathrm{cm} times ) ( 15 c m ) has to be pushed along the floor. The force required will be minimum when the surface in contact with the ground is ( mathbf{A} cdot 8 mathrm{cm} times 15 mathrm{cm} ) surface B. ( 5 mathrm{cm} times 15 mathrm{cm} ) surface c. ( 8 mathrm{cm} times 5 mathrm{cm} ) surface D. force is same for all surfaces |
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| 49 | A ( 10 mathrm{kg} ) block is pulled a along a frictional surface in the form of an are of a circle of radius ( 10 mathrm{m} ). The applied force ( F ) is ( 200 mathrm{N} ) as shown in figure If ( mathrm{a} ) block started from rest at ( mathrm{P} ) A. the velocity at Q would be ( 20 mathrm{m} / mathrm{s} ) B. the velocity at Q would be ( 17 mathrm{m} / mathrm{s} ) C. the velocity at ( Q ) would be ( 15.5 mathrm{m} ). D. the velocity at Q would be ( 18 mathrm{m} / mathrm{s} ) |
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| 50 | 6. A smooth ring A of mass m can slide on a fixed horizontal rod XY. A string tied to the ring passes over a fixed pulley B and carries a block C of mass M(= 2 m) as shown in Fig. 6.286. At an instant the string between the ring and pulley makes an angle with the rod. XO mA V Fig. 6.286 a. Show that if the ring slides with speed v, the block descends with speed v cos 0. b. With what acceleration will the ring start moving if the system is released from rest with = 30°? A . Amanahald an amanth h andal |
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| 51 | ( P ) and ( Q ) are two objects with masses 5 kg and 30 kg respectively. Then A. P has more inertia than ( Q ) B. Q has move inertia than P c. P and Q have the same inertia D. neither P nor Q has any inertia |
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| 52 | 33. A man pulls himself up the 30º incline by the me shown in Fig. 6.318. If the combined mass of the and cart is 100 kg, determine the acceleration of the if the man exerts a pull of 250 N on the rope. Neglectal friction and the mass of the rope, pulleys, and wheels 30° Fig. 6.318 a. 4.5 ms? b. 2.5 ms ? c. 3.5 ms 2 d. 1.5 ms-2 |
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| 53 | The inertia of a moving body makes it: A. stop due to friction B. increase its speed c. decrease its speed D. resist a change in its state of motion |
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| 54 | It is easier to roll a barrel full of coal tar than to pull it because A. the full weight of the barrel comes into play when it is pulledd B. the rolling friction is much less than the sliding friction c. more surface area of the barrel is in contact with the road when it is pulled D. coal tar is a liquid and it flows in the barrel when it is rolled |
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| 55 | A force of 50 dynes is acted on a body of mass ( 5 g ) which is at rest for an interval of 3 seconds, then impulse is ( (text { in } N s) ) A. ( 1.5 times 10^{-3} ) B. ( 1.5 times 10^{-2} ) c. ( 2.5 times 10^{-} 3 ) D. ( 1.5 times 10^{3} ) |
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| 56 | Normal force is A. parallel to the surface B. perpendicular to the surface ( c cdot ) both D. none |
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| 57 | A ball of mass ( mathrm{m} ) is dropped on to a floor from certain height, collision is perfectly elastic and the ball rebounds to the same height and again falls. Find the average force exerted by the ball on the floor during a long time interval. A. mg B. > mg ( mathrm{c} cdot<mathrm{mg} ) D. none of these |
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| 58 | Why are vehicle tyres treaded? A. To increase friction B. To decrease friction c. To multiply friction D. To decrease grip |
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| 59 | Which of the following is used to reduce friction : Streamlines 2. Use of ball bearings 3. Lubrication ( A cdot 1 & 2 ) only B. 1 & 3 only c. ( 2 & 3 ) only D. 1,2 & 3 |
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| 60 | Two billiard balls each of mass ( 0.05 k g ) moving in opposite directios with speed ( 6 m s^{-1} ) collide and rebound with the same speed. What is the impulse imparted to each ball due to the other. |
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| 61 | U. -15L c. -IUL u. – 68. Two blocks A and B of masses m and 2 m, respect are held at rest such that the spring is in natural length. Find out the accelerations of both the blocks just after release. Spring Fig. 6.348 a. gt, gt w100 colm c. 0,0 d. 8 t, c |
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| 62 | Define angle of repose. Deduce its relation with coefficient of limiting friction. |
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| 63 | The vertical section of a road over a canal bridge in the direction of its length is in the form of circle of radius ( 8.9 m . ) Then the greatest speed at which the car can cross this bridge without losing contact with the road at its highest point, the centre of gravity of the car being at a height ( h=1.1 m ) from the ground (Take ( left.g=10 m / s e c^{2}right) ) A. ( 5 mathrm{m} / mathrm{sec} ) в. ( 10 mathrm{m} / mathrm{sec} ) c. ( 15 mathrm{m} / mathrm{sec} ) D. ( 20 mathrm{m} / mathrm{sec} ) |
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| 64 | A body of mass ( m=1 k g ) falls from a height ( h=20 m ) from the ground level a. What is the magnitude of total change in momentum of the body before it strikes the ground? b. What is the corresponding average force experienced by it? ( left(g=10 m s^{-2}right) ) |
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| 65 | A person in a moving with the velocity of train. When he jumps from the train, inertia prohibits him to come at the state of a rest all of sudden. Type 1 for true and 0 for false |
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| 66 | Four blocks of different masses ( left(boldsymbol{m}_{1}=right. ) ( mathbf{1} boldsymbol{k} boldsymbol{g}, boldsymbol{m}_{2}=mathbf{2} boldsymbol{k} boldsymbol{g}, boldsymbol{m}_{3}=mathbf{1} boldsymbol{k} boldsymbol{g} ) and ( boldsymbol{m}_{4}= ) ( 5 k g) ) are connected with light, inextensible strings, as shown in figure. This system is pulled along the frictionless surface by a horizontal force of ( 36 N . ) The force pulling the block of ( operatorname{mass} boldsymbol{m}_{1} ) will be A ( .2 N ) в. ( 4 N ) c. ( 12 N ) D. ( 36 N ) |
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| 67 | In a game of tug of wars, a condition of equilibrium exists. Both the teams pull the rope with a force of ( 10^{4} ) N. The tension in the rope is : ( A cdot 10^{4} N ) B . ( 10^{5} mathrm{N} ) ( c cdot 0 ) D. ( 2 times 10^{4} mathrm{N} ) |
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| 68 | An unbanked curve has a radius of ( 60 m . ) The maximum speed at which a car can make a turn if the coefficient of static friction is ( 0.75, ) is: A . ( 2.1 mathrm{m} / mathrm{s} ) в. ( 145 mathrm{m} / mathrm{s} ) c. ( 21 mathrm{m} / mathrm{s} ) D. ( 7 mathrm{m} / mathrm{s} ) |
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| 69 | Two uniform rods of equal length but different masses are rigidly joined to form an ( L ) shaped body, which is then smoothly pivoted about ( O ) as shown. If the body is in equilibrium in the shown configuration, ratio ( M: m ) will be : ( A ) B. ( c cdot sqrt{2} ) D. ( sqrt{3} ) |
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| 70 | Frictional force always opposes motion of a body. A . True B. False |
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| 71 | A road is ( 8 mathrm{m} ) wide. Its average radius of curvature is ( 40 mathrm{m} . ) The outer edge is above the lower edge by a distance of ( 1.28 mathrm{m} . ) Find the velocity of vehicle for which the road is most suited? ( (boldsymbol{g}= ) ( 10 m / s^{2} ) |
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| 72 | A horizontal force of 10 newton is necessary to just hold a block stationary against a wall, The coefficient of friction between the lock and the wall is 0.2. The weight of block is A. 50 B. 100 N ( c cdot 2 N ) D. 20 N |
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| 73 | A heavy seesaw (i.e., not massless) is out of balance. A light girl sits on the end that is tilted downward, and a heavy body sits on the other side so that the seesaw now balances. If they both move forward so that they are one-half their original distance from the pivot point (the fulcrum) what will happen to the seesaw? A. The side the body is sitting on will tilt downward B. The side the girl is sitting on will once again tilt downward C. Nothing; the seesaw will still be balanced. D. It is impossible to say without knowing the masses and the distances. |
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| 74 | A metal bar ( 70 mathrm{cm} ) long and ( 4.00 mathrm{kg} ) in mass supported on two knife-edges placed ( 10 mathrm{cm} ) from each end. ( mathrm{A} 6.00 mathrm{kg} ) load is suspended at ( 30 mathrm{cm} ) from one end. Find the reactions at the knife- edges. (Assume the bar to be of uniform cross section and homogeneous.) ( mathbf{A} cdot 45 N ) and ( 43 N ) B. ( 50 N ) and ( 35 N ) ( mathbf{c} .55 N ) and ( 43 N ) D. ( 54 N ) and ( 30 N ) |
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| 75 | 40. Mark the correct statement: a. Velocity of the body is maximum when force acting on the body is maximum for the first time. b. The velocity of the body becomes maximum when force acting on the body becomes zero again c. When force becomes zero again, velocity of the body also becomes zero at that instant. d. All of the above |
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| 76 | A block is placed on a rough floor and a horizontal force ( boldsymbol{F} ) is applied on it. The force of friction ( boldsymbol{f} ) by the floor on the block is measured for different values of ( F ) and a graph is plotted between them. This question has multiple correct options A. The graph is a straight line of slope ( 45^{circ} ) B. The graph is a straight line parallel to the ( F ) -axis. C. The graph is a straight line of slope ( 45^{circ} ) for small ( F ) and a straight line parallel to the ( F ) -axis for large ( F ) D. There is a small kink on the graph. |
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| 77 | A tennis ball and a cricket ball, both are stationary. To start motion in them A. a less force is required for the cricket ball than for the tennis bal B. a less force is required for the tennis ball than for the cricket ball c. same force is required for both the balls D. nothing can be said |
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| 78 | Boats and aeroplanes are ( ldots ldots . . . . . . . . ) so as to reduce fluid friction.fill in the blank. A. large B. broader c. streamlined D. bigger |
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| 79 | A small block of mass ( m ) is lying at a rest at point ( boldsymbol{P} ) of wedge having a smooth semicircular track of radius ( boldsymbol{R} ) The maximum value of horizontal acceleration ( a_{0} ) of wedge so that mass can just reach the point ( Q ? ) A ( . g / 2 ) B. ( sqrt{g} ) ( c ) D. not possible |
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| 80 | A ball of mass ( frac{1}{10} mathrm{kg} ) is thrown against a wall. It strikes the wall normally with a velocity of ( 30 m s^{-1} ) and rebounds from there with a velocity ( 20 m s^{-1} ). The impulse of the force exerted by the ball on the wall is A. 0.5Ns B. 50Ns ( c cdot 5 N s ) D. 1Ns |
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| 81 | A ( 10 mathrm{N} ) force applied on a body produces in it an acceleration of ( 2 m s^{-2}, ) then the mass of the body is ( A cdot 10 mathrm{kg} ) B. 2 kg ( c .5 mathrm{kg} ) ( D cdot 6 mathrm{kg} ) |
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| 82 | A wedge of mass ( 10 mathrm{kg} ) is moving rightwards. A block of mass ( 10 k g ) is placed on it. Friction coefficient between wedge and block is ( 0.8 . ) Then ( left[text {take } g=10 m / s^{2}right] ) This question has multiple correct options A. If wedge is moving with constant velocity then friction acting on block is 64N B. If wedge is moving with constant velocity then acceleration of block is zero C. If wedge is moving with ( a=2 hat{i} m / s^{2} ) then friction acting on block is ( 44 mathrm{N} ) D. If wedge is moving with ( a=10 hat{i} m / s^{2} ) then friction is zero |
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| 83 | List the effects of force with example | 11 |
| 84 | An object of mass ( 2 mathrm{kg} ) is sliding with a constant velocity of ( 4 m s^{-1} ) on a frictionless horizontal table. The force required to keep the object moving with the same velocity is: A. 32 N B. on ( c cdot 2 n ) ( D cdot 8 N ) |
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| 85 | Cleaning of dust from carpet is due to A. Inertia of motion B. Inertia of rest c. Inertia of direction D. Momentum |
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| 86 | A body of mass ( 6 mathrm{kg} ) is moving with uniform velocity along a straight line when a force of ( 12 mathrm{N} ) is acting on it. If ( boldsymbol{g}=mathbf{1 0 m} boldsymbol{s}^{-2}, ) find the frictional force acting on the body. ( A cdot 6 N ) B. 12 N ( c cdot 18 N ) D. 24 N |
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| 87 | A body of mass ( 5 k g ) is acted on by a net force ( boldsymbol{F} ) which varies with time ( t ) as shown in graph. Then the net momentum in ( S I ) units gained by the body at the end of 10 seconds is ( A ) в. 100 ( c .140 ) D. 200 |
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| 88 | If we imagine ideally smooth surfaces kept in contact, the frictional force acting between them is : A. zero B. a finite value but not zero c. very large D. we can’t predict |
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| 89 | The given rod is uniform and has a mass m. Find the tension in the string. A ( cdot frac{(m g sin theta)}{2} ) B. ( frac{m g sin }{2} ) c. ( frac{(m g cos theta)}{2} ) D. ( frac{m g}{2} ) E . ( m ) |
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| 90 | calculate the angle of banking of a smooth curved road of radius ( 100 mathrm{m} ) if vehicles can safely travel along it with a speed of ( 108 k m / h ) |
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| 91 | Q Type your question along horizontal rails from left to right At time ‘t’, it retards. Then the reaction by the floor on the box is given best by? 4 B. ( c ) ( D ) |
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| 92 | A body slipping on a rough horizontal plane moves with a deceleration of 4.0 ( m / s^{2} . ) What is the coefficient of kinetic friction between the block and the plane? |
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| 93 | o kg and 35 kg and D as shown and Illustration 6.5 Two particles of masses 10 kg an are connected with four strings at points B and D. in Fig. 6.22. LU FC f TTTTTTTTT 37° 100 N 350 N Fig. 6.22 Determine the tensions in various segments of the string. |
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| 94 | Momentum is a measure of quantity of motion. A . True B. False |
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| 95 | 7. An insect crawls up a hemispherical surface very slowly. The coefficient of friction between the insect and the surface is 1/3. If the line joining the center of the hemispherical surface Fig. 7.359 to the insect makes an angle a with the vertical, the maximum possible value of u. is given (IIT JEE, 2001) a. cot a=3 b. tan a=3 c. sec a=3 d. cosec a=3 by |
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| 96 | Explain why objects moving in fluids must have special shapes. | 11 |
| 97 | A block of metal weighing ( 2 k g ) is resting on a frictionless plane. It is struck by a jet releasing water at a rate of ( 1 k g / s ) and at a speed of ( 5 m / s ).The initia acceleration of the block will be A ( .2 .5 m / s^{2} ) B. ( 0.5 m / s^{2} ) c. ( 10 m / s^{2} ) D. ( 20 m / s^{2} ) |
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| 98 | A body is said to be under balanced forces when the resultant force acting on the body is A. Unity B. zero c. Infinite D. None of these |
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| 99 | If a cyclist takes a turn of radius ( 10 m ) going at a speed of ( 10 mathrm{m} / mathrm{s} ) then find the angle through which he must bend in order to avoid overturning. [asume ( boldsymbol{g}= ) ( left.10 m / s^{2}right] ) A ( .90^{circ} ) B. ( 0^{circ} ) ( c cdot 45^{circ} ) D. 30 |
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| 100 | A person is moving on a rough horizontal surface towards east. Then the direction of friction force is towards: A. west B. East C. Friction does not act D. Information insufficient |
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| 101 | Find the magnitude and the direction of acceleration of the body ( m_{2} ) when the formerly stationary system of masses starts moving. A ( .5 g ) B. ( 0.05 g ) c. ( 0.005 g ) D. ( 0.5 g ) |
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| 102 | Block A mass 2 kg is placed over a block B mass 8 kg. The combination is placed on a rough horizontal surface. If ( mathrm{g}=10 mathrm{ms}^{-2} ) coefficient offiction between ( mathbf{B} ) and floor ( =0.5, ) coefficient offfiction betweenA and ( mathrm{B}=0.4 ) and a horizontal force on ( 10 mathrm{N} ) is placed of8 ( mathrm{kg} ) block, then the force friction between ( A ) and B is: A. ( 100 N ) B. 50N c. ( 40 mathrm{N} ) D. None of these |
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| 103 | If a uniform beam of ( 1 mathrm{m} ) is balanced as shown above, what would be the moment of force ( F ) about point ( W ? ) ( mathbf{A} cdot 110 N mathrm{cm} ) в. ( 40 mathrm{N} mathrm{cm} ) c. ( 220 mathrm{N} mathrm{cm} ) D. ( 80 mathrm{N} ) cm |
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| 104 | Inertia of a body depends on: A. Mass of the body B. Velocity of the body c. Acceleration of the body D. Energy of the body |
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| 105 | Two blocks ( A ) and ( B ) of mass ( m_{A}=10 k g ) and ( m_{B}=20 k g ) are place on rough horizontal surface. The blocks are connected with a string. If the coefficient of friction between block ( A ) and ground is ( mu_{A}=0.9 ) and between block B and ground is ( mu_{B}=0.3, ) find the tension in the string in situation as shown in Fig. Forces ( 120 mathrm{N} ) and ( 100 mathrm{N} ) start acting when system is at rest? |
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| 106 | 2. In the system shown in Fig. 6.386, masses of the blocks are such that when system is released, the acceleration of pulley P, is a upwards and the acceleration of block 1 is a, a upwards. It is found that the acceleration of block 3 is same as that of 1 both in magnitude and direction. Fig. 6.386 Given that a, > > a,/2. Match the following: Column I Column II Acceleration of 2 2ata, a. ii. Acceleration of 4 b. 2a – ai iii. Acceleration of 2 w.r.t. 3 c. Upwards iv. Acceleration of 2 w.r.t. 4 d. Downwards |
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| 107 | The friction coefficient between an athlete’s shoes and the ground is 0.90 Suppose a superman wears these shoes and races for ( 50 mathrm{m} ). There is no upper limit on his capacity of running at high speeds. Suppose he takes exactly this minimum time to complete the ( 50 mathrm{m} ) what minimum time will he take to stop? |
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| 108 | Which of the following has more inertia ( ? ) A five-rupee coin or a one-rupee coin. |
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| 109 | Illustration 7.41 A block of mass 1 kg is tied to a string of length 1 m, the other end of which is fixed. The block is moved on a smooth horizontal table with constant speed 10 ms. Find the tension in the string. |
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| 110 | A force of 64 dynes is inclined to the horizontal at an angle of ( 60^{circ} . ) Find the acceleration in a mass of 8 g, which moves in a horizontal direction. ( A cdot 4 mathrm{cm} mathrm{s}^{-2} ) B. ( 2 mathrm{cm} mathrm{s}^{-2} ) ( c cdot 8 mathrm{cm} mathrm{s}^{-2} ) ( D cdot 6 mathrm{cm} mathrm{s}^{-2} ) |
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| 111 | Assertion On a rainy day it is difficult to drive a car or bus at high speed. Reason The value of coefficient of friction is lowered due to wetting of the surface. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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| 112 | Assertion Horse has to pull a cart harder during the first few steps of his motion. Reason The first few steps are always difficult. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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| 113 | Why are seat belts designed in cars to stretch somewhat in a collision? | 11 |
| 114 | ( 11 00 2. Statement I: It is easier to pull a heavy object than to push it on a level ground. Statement II: The magnitude of frictional force depends on the nature of the two surfaces in contact. (IIT JEE, 2008) |
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| 115 | Two identical cylinders ( A ) and ( B ) with frictionless pistons contain the same ideal gas at same temperature and the same volume ( V ). The mass of gas ( A ) is ( m_{A} ) and that of ( B ) is ( m_{B} . ) The gas in each cylinder is allowed to expand isothermally to the same final volume 2V. The change in the pressure in ( A ) and B are found to be ( Delta P ) and ( 1.5 Delta P ) respectively. Then ( mathbf{A} cdot 4 m_{A}=9 m_{B} ) B. ( 3 m_{A}=3 m_{B} ) ( mathbf{c} cdot 3 m_{A}=2 m_{B} ) D. ( 9 m_{A}=4 m_{B} ) |
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| 116 | Distinguish between static friction, limiting friction and kinetic friction.How do they vary with the applied force? Explain by diagram. |
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| 117 | Sliding friction is ( ldots ldots . . . . . . . . ) than rolling friction.fill in the blank. A. greater B. less c. same as D. cant say |
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| 118 | A small disc ( A ) is placed on an inclined plane forming an angle ( alpha ) with the horizontal (shown in figure above) and is imparted an initial velocity ( v_{0} ). Find how the velocity of the disc depends on the angle ( varphi ) if the friction coefficient ( k=tan alpha ) and at the initial moment ( varphi_{0}=frac{pi}{2} ) A ( cdot v=frac{v_{0}}{1+2 cos varphi} ) в. ( v=frac{v_{0}}{1-2 cos varphi} ) c. ( v=frac{v_{0}}{1+cos varphi} ) D. ( v=frac{v_{0}}{1-cos varphi} ) |
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| 119 | What is the equation of motion for the rocket, if ( m ) is the mass of the rocket at a given moment, ( vec{w} ) is its acceleration, and ( overrightarrow{boldsymbol{F}} ) is the external force. ( mathbf{A} cdot m vec{w}=vec{F}-2 mu vec{u} ) в. ( m vec{w}=vec{F}+mu vec{u} ) C ( . m vec{w}=vec{F}-3 mu vec{u} ) D ( cdot m vec{w}=vec{F}-mu vec{u} ) |
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| 120 | A block of mass ( 5 k g ) is (i) pushed in case ( (A) ) and (ii) pulled in case ( (B), ) by force ( boldsymbol{F}=mathbf{2 0} boldsymbol{N}, ) making an angle of ( boldsymbol{3 0}^{boldsymbol{o}} ) with the horizontal, as shown in the figures. The coefficient of friction between the block and floor is ( mu=0.2 ) The difference between the accelerations of the block, in case (B) and case (A) will be: ( left(g=10 m s^{-2}right) ) ( (mathrm{B}) ) ( mathbf{A} cdot 0 m s^{-2} ) B. ( 0.8 m s^{-2} ) c. ( 0.4 m s^{-2} ) D. ( 3.2 mathrm{ms}^{-2} ) |
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| 121 | If the mass of the body is doubled what’ll happen to its acceleration if the same force applied. | 11 |
| 122 | According to the Newton’s third law of motion, action and reaction pair: A. always act on the same body B. always act on different bodies in opposite directions C. have same magnitude and directions D. act on either body at normal to each other |
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| 123 | A car executes a turn of radius ( 22 m ) on a banked road while travelling at a speed of ( 45 k m / h ). If the height of the outer edge above the inner edge of the road is ( 1.1 m, ) what is the breadth of the road? ( (text { in } boldsymbol{m}) ) A. 1.745 B. 1.569 c. 1.875 D. 1.236 |
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| 124 | T ext Statement I: A concept of pseudo forces is valid both for inertial as well as non-inertial frame of reference. Statement II: A frame accelerated with respect to an inertial frame is a non-inertial frame. |
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| 125 | s the block gets 50. At what angle with horizontal does the block separated from the track? d. never leaves contact with the track |
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| 126 | Two particles of masses ( m_{1} ) and ( m_{2} ) are released from rest on a smooth wedge of mass ( M, ) then This question has multiple correct options A. Reaction force on the wedge due to ground is equal to ( left(m_{1}+m_{2}+Mright) g ) B. The wedge remains at rest if ( m_{1}=m_{2} ) C ‘ the wedge remains stationary if ( frac{left(m_{1}right.}{m_{2}}=tan theta ) D. if ( left(m_{1}>m_{2}, ) the wedge will accelerate towards right right. |
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| 127 | A false balance has equal arms. An object weights ( boldsymbol{w}_{1} ) when placed in one pan and ( w_{2} ) when placedin the other pan. Then weight w of the object is в. ( frac{w_{1}+w_{2}}{2} ) ( ^{mathbf{c}} cdotleft(frac{w_{1}^{2}+w_{2}^{2}}{2}right)-1 ) ( mathbf{D} cdot sqrt{w_{1}^{2}+w_{2}^{2}} ) |
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| 128 | The graph below shows the momentum of an object with respect to time. The object is initially travelling in the positive direction. Which section has the greatest magnitude of force acting on the object? ( A ) в. c. 5 D. 283 E. 3 & 5 |
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| 129 | A spring of force constant ( k ) is cut into two pieces such that one piece is twice as long as the other. Then the longer piece will have a force constant of: ( mathbf{A} cdot 3 k ) в. ( frac{2 k}{3} ) ( c cdot frac{3 k}{2} ) D. ( 6 k ) |
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| 130 | ( mathbf{A} ) ( 40 mathrm{kg} ) box rests on the horizontal floor of truck which is initially at rest on a horizontal road. The coefficient of kinetic friction between the floor and the box is 0.2 . The truck at time ( t=0 ) accelerates constantly at ( 5 m s^{-2} ) and the box is ( 6 m ) away from the rear opening of the truck. Find (i) the time ( ^{prime} boldsymbol{t}^{prime} ) when the boxjust falls off the floor of the truck (ii) the distance travelled by the truck during the interval (iii) distance covered by the box with respect to road. |
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| 131 | 3. The spring force is given by F = -kx, here k is a constant and x is the deformation of spring. The F-x graph is F FI F |
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| 132 | As the train starts moving; a man sitting inside leans backwards because of : A. Inertia of rest B. Inertia of motion c. Moment of inertia D. conservation of mass |
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| 133 | Inertia is A. a property of matter B. a type of force C. the speed of an object D. none of the above |
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| 134 | Two masses of ( 1 mathrm{gm} ) and ( 4 mathrm{gm} ) are moving with equal kinetic energies.The ratio of the magnitudes of their linear momenta is: ( A cdot 4: 1 ) B. 2:1 ( c cdot 1: 2 ) D. 1:16 |
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| 135 | Maximum force exerted by the bat on the ball is: A ( .2500 N ) в. ( 5000 N ) c. ( 7500 N ) D. ( 1250 N ) |
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| 136 | In the figure shown, a cubical block is held stationary against a rough wall by applying force ( F ) then, incorrect statement among the following is: A. frictional force, ( f=M g ) B. ( F=N, N ) is normal reaction C. F does not apply any torque D. N does not apply any torque |
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| 137 | Statement A: Shock absorbers reduce the magnitude of change in momentum Statement B: Shock absorbers increase the time of action of impulsive force A. A & B are correct B. A & B are wrong c. A is correct and B is wrong D. A is wrong and B is correct |
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| 138 | Deformation of surfaces occurs due to which type of friction among the following? A. Static friction B. Rolling friction C. Fluid friction D. None of these |
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| 139 | An object of mass ( 1 k g ) is dropped from a height of 20 m. It hits the ground and rebounds with the same speed. Find the change in momentum. (Take ( boldsymbol{g}= ) ( left.10 m / s^{2}right) ) |
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| 140 | Choose the correct statements. The coefficient of static friction depends on This question has multiple correct options ( A ). the material of the bodies in contact B. quality of machining of the surfaces in contact C. presence of foreign matter between the surfaces D. area of the surfaces in contact |
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| 141 | Fill in the blanks with suitable words: Newtons first law of motion is also called law of |
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| 142 | A man in a minivan rounds a circular turn at a constant speed. Which of the following would cause the minivan to experience less acceleration? A. traveling faster B. traveling around a turn with a smaller circular radius C. traveling with more weight in the van D. traveling around a turn with a greater circular radius E. traveling the opposite direction around the same turn |
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| 143 | State whether True or False: The angle through which cyclist should bend will be greater for the sharper curve A. True B. False |
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| 144 | The blocks are attached by an in extensible light string and pulled vertically upward by force ( 100 mathrm{N} ) as shown. Find the common acceleration and tension the string. |
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| 145 | 7. A block of mass m is placed in contact with one smooth tube of mass M. A horizontal force Facts on the tube in each case (i) and (ii). Then, M M Fig. 6.362 a. am = 0 and am =- M b. am = AM = 7 M in(i) + m F – c. Am = QM-M+m in (ii) mF d. Force on m is mr_ in (ii) M + m |
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| 146 | Discuss motion of a car along a banked road with figure and show that ( v_{max }= ) ( left(R g frac{mu_{s}+tan theta}{1-mu, tan theta}right)^{frac{1}{2}} ) |
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| 147 | Two blocks are arranged as shown in the figure. Find the ratio of ( a_{1} / a_{2} .left(a_{1} ) is right. acceleration of ( boldsymbol{m}_{1} ) and ( boldsymbol{a}_{1} ) that of ( boldsymbol{m}_{2} ) ). |
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| 148 | A mass of ( 10 k g ) is suspended by a rope of length ( 4 m, ) from the ceiling. A force ( F ) is applied horizontally at the mid-point of the rope such that the top half of the rope makes an angle of ( 45^{circ} ) with the vertical. Then F equals: (Take ( boldsymbol{g}= ) ( 10 m s^{-2} ) and the rope to be massless) A . ( 70 N ) B. ( 75 N ) c. ( 100 N ) D. ( 90 N ) |
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| 149 | Illustration 7.8 Determine the magnitude of frictiona and acceleration of the block in each of the following frictional force following cases 5 kg 5 kg 12kg 100 N- 500 N – 37 H =0.3 He = 0.3 Mg = 0.4 Case I 500 N He=0.3 Hy = 0.4 Case II Fig. 7.22 u, = 0.4 Case II |
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| 150 | Consider the quantities, pressure, power, energy, impulse, gravitational potential, electrical charge, temperature, area. Out of these, the only vector quantities are A. Impulse, pressure and area B. Impulse and area c. Area and gravitational potential D. Impulse and pressure |
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| 151 | Two bodies of unequal masses possess the same momentum. Which of the following can be concluded? A. Heavier mass possesses lesser K. B. The masses of the two bodies are in the direct ratio of their velocities c. Lighter mass possesses less K.E. D. Both (A) and (B) |
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| 152 | A force of 5 N acts on a body of weight ( 9.8 mathrm{N} . ) What is the acceleration produced in ( boldsymbol{m} / boldsymbol{s e c}^{2} ) A. ( 49.00 mathrm{m} / mathrm{s}^{wedge 2} ) B. ( 5.00 mathrm{m} / mathrm{s}^{2} 2 ) c. ( 1.46 mathrm{m} / mathrm{s}^{2} ) ? D. ( 0.5 mathrm{m} / mathrm{s}^{wedge} 2 ) |
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| 153 | A plank with a box on it at one end is gradually raised about the other end. As the angle of inclination with the horizontal reaches ( 30^{circ}, ) the box starts to slip and slides 4.0 m down the plank in 4.0 ( s ). The coefficients of static and kinetic friction between the box and the plank will be, respectively A. 0.4 and 0.3 B. 0.6 and 0.6 c. 0.6 and 0.5 D. 0.5 and 0.6 |
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| 154 | Determine the magnitude of frictional force ( f ) in each of the following cases: c) |
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| 155 | The minimum velocity (in ( mathrm{m} / mathrm{s} ) ) with which a car driver must traverse a flat curve of radius ( 150 mathrm{m} ) and coefficient of friction 0.6 to avoid skidding is: A. ( 60 mathrm{m} / mathrm{s} ) B. 30 ( mathrm{m} / mathrm{s} ) ( c cdot 15 m / s ) D. 25 ( mathrm{m} / mathrm{s} ) |
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| 156 | 36. Which of the curves in graph correctly gives the acceleration magnitude as a function of the ratio m/Mto (vertical axis is for acceleration)? a. 1 b. 2 c. 3 d. 4 |
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| 157 | For the system shown in figure, the pulleys are light and frictionless. The tension in the string will be: A ( cdot(2 / 3) m g sin theta ) B. ( (3 / 2) m g sin theta ) ( c .(1 / 2) m g sin theta ) D. ( 2 m g sin theta ) |
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| 158 | A rod of mass ( mathrm{M} ) kg and length ( mathrm{L} mathrm{m} ) is bent in the form of an equilateral triangle as shown in figure. The moment of inertia of the triangle about a vertical axis perpendicular to the plane of the triangle and passing through the centre (in units of ( mathrm{kg} boldsymbol{m}^{2} ) ) is? A ( cdot frac{M L^{2}}{12} ) B. ( frac{M L^{2}}{54} ) c. ( frac{M L^{2}}{162} ) D. ( frac{M L^{2}}{108} ) |
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| 159 | A ball of mass ( 20 g ) hits a wall at an angle ( 45^{circ} ) with a velocity of ( 15 m s^{-1} . ) If the ball rebounds at ( 90^{circ} ) to the direction of incidence, calculate the impulse received by ball. |
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| 160 | A ( 1.0 mathrm{kg} ) box on a horizontal surface experiences a 3.0 N horizontal frictional force. How much force must be applied horizontally to the box to cause it to accelerate at ( 1.0 mathrm{m} / mathrm{s}^{2} ) ? A . ( 1.0 mathrm{N} ) в. 2.0 N c. 3.0 N D. 4.0 N E. ( 5.0 mathrm{N} ) |
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| 161 | A system consists of two identical small balls of mass 2 kg each connected to the two ends of a 1 m long light rod. The system is rotating about a fixed axis through the centre of the rod and perpendicular to it at an angular speed of 9 rad/s. An impulsive force of average magnitude ( 10 N ) acts on one of the masses in the direction of its velocity for ( 0.20 s . ) Calculate the new angular velocity of the system. |
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| 162 | If the K.E. of a body is increased by ( 300 % ) its momentum will increase by A. ( 100 % ) B. ( 150 % ) c. ( sqrt{300 %} ) D. ( 175 % ) |
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| 163 | What is the impulse of force shown in the following fingre? A. 205 Ns B. 450 Ns ( c .800 mathrm{Ns} ) D. 1000 Ns |
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| 164 | Assertion A body on an inclined plane just tends to slide down if the angle of inclination is equal to angle of friction. Reason When the angle of inclination is equal to the angle of friction, the component of weight parallel to the plane is just sufficient to overcome the frictional force. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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| 165 | Five forces ( vec{F}_{1}, vec{F}_{2}, vec{F}_{3}, vec{F}_{4} ) and ( vec{F}_{5} ) are acting on a particle of mass ( 2.0 mathrm{kg} ) so that it is moving with ( 4 m / s^{2} ) in east direction. If ( vec{F}_{1} ) force is removed, then the acceleration becomes ( 7 mathrm{m} / mathrm{s}^{2} ) in north, then the acceleration of the block if only ( vec{F}_{1} ) is acting will be : A ( cdot 16 m / s^{2} ) B . ( sqrt{65} mathrm{ms}^{2} ) c. ( sqrt{260} mathrm{ms}^{2} ) D. ( sqrt{3} 3 m s^{2} ) |
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| 166 | If both the mass of a body and the force acting on it are doubled, the acceleration: A. is doubled B. is halved c. becomes zero D. remains the same |
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| 167 | Fig. 7.8 Illustration 7.2 A block of mass m = 1 ko is at rest on a rough horizontal surface having coefficient of static friction us = 0.2 and kinetic force u = 0.15. Discuss the frictional forces if a horizontal force F is applied on the block. S.No. Value of F 1N 2N 2.5 N |
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| 168 | A hammer weighing ( 3 mathrm{kg}, ) moving with a velocity of ( 10 mathrm{m} / mathrm{s}, ) strikes against the head of a spike and drives it into a block of wood. If the hammer comes to rest in 0.025 s, the impulse associated with the spike will be : ( A cdot ) 30 Ns B. -30Ns c. 15 Ns D. -15 Ns |
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| 169 | A batsman hits back a ball straight in the direction of the bowler without changing its initial speed of ( 12 m s^{-1} . ) If the mass of the ball is ( 0.15 k g ) determine the change in momentum of the ball. (Assume linear motion of the ball) A. ( 3.6 k g m / s ) в. ( 5 k g m / s ) c. ( 3.5 k g m / s ) D. ( 7 k g m / s ) |
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| 170 | A boy rolls a rubber ball on a wooden surface. The ball travels a short distance before coming to rest. To make the same ball travel longer distance before coming to rest, he may A. spread a carpet on the wooden surface. B. cover the ball with a piece of cloth c. sprinkle talcum powder on the wooden surface. D. sprinkle sand on the wooden surface |
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| 171 | Explain why pulling is easier than pushing with a neat sketch on a rough horizontal plane. |
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| 172 | T 5. In order to raise a mass of 100 kg, a man of mass 60 kg fastens a rope to it and passes the rope over a smooth pulley. He climbs the rope with acceleration 5g/4 relative to the rope. The tension in the rope is (take g = 10 ms) 4875 4875 -N a. -N Fig. 6.297 4875 N d. 4875 |
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| 173 | f velocity of C immediately after collision becomes ( v_{0} / 2 ) in the initial direction of motion, the impulse due to string on sphere ( A ) is : A. ( frac{m v_{0}}{8} ) в. ( frac{m v_{0}}{2} ) c. ( frac{sqrt{m v_{0}}}{4} ) D. none of thes |
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| 174 | State first law of motion and explain it | 11 |
| 175 | Assertion A sphere is performing pure rolling on a rough horizontal surface with constant angular velocity,frictional force acting on the sphere is zero Reason Velocity of conduct point is zero. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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| 176 | Two objects rest on a seesaw. The first object has a mass of ( 3 mathrm{kg} ) and rests 10 ( m ) from the pivot. The other rests ( 1 mathrm{m} ) from the pivot. What is the mass of the second object if the seesaw is in equilibrium? ( A cdot 0.3 mathrm{kg} ) B. 3 kg ( c cdot 10 mathrm{kg} ) D. 30 kg E. ( 50 mathrm{kg} ) |
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| 177 | Friction does not depend on the nature of the surface in contact. A. True B. False c. Ambiguous D. Data insufficient |
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| 178 | An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. This statement is known as: A. Newton’s first law of motion B. Newton’s second law of motion c. Newton’s third law of motion D. Newton’s law of gravitation |
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| 179 | A block of mass ( 20 mathrm{kg} ) is acted upon by a force ( boldsymbol{F}=mathbf{3 0} boldsymbol{N} ) at an angle ( mathbf{5 3}^{mathbf{0}} ) with the horizontal in downward direction as shown. The coefficient of friction between the block and the horizontal surface is ( 0.2 . ) The friction force acting on the block by the ground is ( (g= ) ( left.10 m / s^{2}right) ) A . 40.0 B. 30.0 N c. ( 18.0 mathrm{N} ) D. 44.8 N |
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| 180 | OUV 40. A block of metal weighing 2 kg is resting on a frictionless plane. It is struck by a jet releasing water at a rate of 1 kg sand at a speed of 5 ms. The initial acceleration of the block is Block 2 kg Fig. 6.323 b. 25 m.-2 c. 26 ms-2 d. ms-2 |
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| 181 | A machine gun fires bullets of ( 50 mathrm{gm} ) at the speed of ( 1000 mathrm{m} / mathrm{sec} . ) If an average force of ( 200 mathrm{N} ) is exerted on the gun, the maximum number of bullets fired per minutes is: A . 240 B. 180 ( c cdot 60 ) D. 30 |
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| 182 | What is an expression for the force due to gravity on a body of mass ( m ) ? ( mathbf{A} cdot F=0 ) В. ( F=m / g ) c. ( F=g ) D. ( F=m g ) |
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| 183 | A heavy chain with a mass per unit length ( p ) is pulled by the constant force ( F ) along a horizontal surface consisting of a smooth section and rough section. The chain is initially at rest on the rough surface with ( boldsymbol{x}=mathbf{0} . ) If the coefficient of kinetic friction between the chain and the rough surface is ( mu_{k} ) determine the velocity ( v ) of the chain when ( x=L . ) The force ( F ) is greater than ( mu_{k}, p g L ) in order to initiate the motion. ( ^{text {A }} cdot sqrt{frac{2 F}{P}-mu_{k} g L} ) в. ( sqrt{frac{F}{P}-mu_{k} g L} ) ( c ) |
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| 184 | Reason out in which case the frictional force between the car and the road is less. |
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| 185 | Guess and write why does pole vault jumper land on thick mats of foam? | 11 |
| 186 | A bullet of mass ( 0.1 mathrm{kg} ) moving horizontally with a velocity of ( 20 mathrm{m} / mathrm{s} ) strikes a target and brought to rest in 0.1 s. Find the impulse and average force of impact. |
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| 187 | Graphite powder is used in machines to A. enhance friction B. enhance profit c. reduce friction D. reduce efficiency |
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| 188 | 99. In Fig. 8.271, the ball A is released from rest, when the spring is at its natural (unstretched) length. For the block B of mass M to leave contact with ground at some stage, the minimum mass of A must be QQQQQ ОА a. 2M c. M/2 Fig. 8.271 b. M d. M14 . . betoof an |
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| 189 | Why is it dangerous to jump out of a moving bus? |
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| 190 | Assertion The total momentum of an isolated system of particles is conserved. Reason The law of conservation of momentum follows from the second and third law of motion. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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| 191 | A rain drop of mass ( 0.1 g ) is falling with uniform speed of ( 10 mathrm{cm} / mathrm{s} ). What is the net force the drop? A ( cdot 10^{-2} N ) В. ( 10^{-3} N ) c. ( 2 times 10^{-3} N ) D. zero |
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| 192 | A light body moving at some speed collides with a heavier body. Which of the following statements is true? I. Heavier body applies a greater impulse on the lighter body. II. The lighter body experiences a greater change of momentum. III. Acceleration of the lighter body will be more than the acceleration of the heavier body. A. I and II only B. II only C. III only D. II and III only E . ।, II, and III |
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| 193 | Which of the following motion of law is (are) involved in the motion of the rocket? This question has multiple correct options |
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| 194 | powder sprinkled on a carrom board A. magnifies friction. B. reduces friction c. removes friction. D. does not affect friction |
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| 195 | A car accelerates on a horizontal road due to the force exerted by: A. the engine of the ear B. the driver of the car c. the earth D. the road |
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| 196 | Assertion Pulling a lawn roller is easier than pushing it. Reason pulling decreases the apparent weight as the vertical component of the pulling force acts upward. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion. B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion. C. Assertion is correct but Reason is incorrect. D. Both Assertion and Reason are incorrect. |
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| 197 | State whether given statement is True or False. An object moving on a frictionless horizontal surface should move with constant velocity A. True B. False |
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| 198 | Impulse is a scalar quantity. State true or false. A . True B. False |
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| 199 | A lead block is suspended from your hand by a string. The reaction due to the force of gravity on the block is the force exerted by : A. The string on the block B. The block on the string c. The string on the hand D. The block on Earth |
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| 200 | A fricionless wire ( A B ) is fixed on sphere of radius R. A very small particle slips on the wire. The journey from ( A ) to ( B ) is performed in time A .2 Rg ( cos theta ) B. ( 2 sqrt{R g} cos theta ) ( c cdot 2 sqrt{frac{R}{g}} ) ( 0.2 sqrt{frac{9}{2}} ) |
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| 201 | State whether the given statement is True or False:
You find your mass to be ( 42 mathrm{kg} ) on a weighing machine. You can say that your mass is more or less than ( 42 mathrm{kg} ) |
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| 202 | The Sl unit of momentum is : A ( cdot k g m s^{-1} ) в. ( k g m s^{-2} ) c. ( k g m s^{2} ) D. ( k g m^{-1} s^{-1} ) |
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| 203 | The coefficient of static friction between the two blocks shown in figure is ( mu ) and the table is smooth.What maximum horizontal force ( F ) can be applied to the block of mass ( mathrm{M} ) so that the blocks move together? |
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| 204 | It is advised to tie any luggage kept on the roof of the bus with a rope.Why? | 11 |
| 205 | A coin flicked across a table will stop, because: A. It is heavy B. No force is acting on it c. Earth attracts the coin D. Table exerts a frictional force |
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| 206 | A cricket ball of mass 150 gram moving with a velocity of ( 12 mathrm{m} / mathrm{s} ) strikes against the bat. It rebounces with a velocity of ( 20 mathrm{m} / mathrm{s} . ) The ball remains in touch with the batfor 0.01 second. The average force applied by the bat on the ball is A. 840 Newton B. 480 Newton c. 804 Newton D. 408 Newton |
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| 207 | An athlete of mass ( 70.0 mathrm{kg} ) applies a force of ( 500 mathrm{N} ) to a ( 30.0 mathrm{kg} ) luge, which is initially at rest, over a period of 5.00 s before jumping onto the luge. Assuming there is no friction between the luge and the track on which it runs, what is its velocity after the athlete jumps on? A. ( 12.5 mathrm{m} / mathrm{s} ) B. 25.0 ( mathrm{m} / mathrm{s} ) c. ( 35.7 mathrm{m} / mathrm{s} ) D. 83.3 ( mathrm{m} / mathrm{s} ) E . ( 100 mathrm{m} / mathrm{s} ) |
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| 208 | A rocket is moving at a constant speed in space by burning its fuel and ejecting out the burnt gases through a nozzle. There is a change in: A. momentum of the rocket ( c cdot operatorname{both} A & B ) D. None of the above |
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| 209 | The magnitude of a frictional force depends on: This question has multiple correct options A. the surface area of contact B. the weight of the object C. the nature of the surface in contact D. none |
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| 210 | 3. Figure 6.393 represents a painter in a crate which hangs alongside a building. When the painter of mass 100 kg pulls the rope, the force exerted by him on the floor of the crate is 450 N. If the crate weighs 25 kg, find the acceleration Fig. 6.393 (in ms) of the painter. |
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| 211 | A monkey of mass ( 40 mathrm{kg} ) climbs on a massless rope of breaking strength 600 N. The rope will break if the monkey ( left(boldsymbol{g}=mathbf{1 0 m} / boldsymbol{s}^{mathbf{2}}right) ) A. climbs up with a uniform speed of ( 5 mathrm{m} / mathrm{s} ) B. climbs up with an acceleration of ( 6 m / s^{2} ) C . climbs down with an acceleration of ( 4 mathrm{m} / mathrm{s}^{2} ) D. Moves down with a uniform speed of ( 5 mathrm{m} / mathrm{s} ) |
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| 212 | A block of ( A ) of ( operatorname{mass} M_{A}=1 ) kg is kept on a smooth horizontal surface and attached by a light thread to another block B of mass ( M_{B}=2 k g . ) Block B is resting on ground, and thread and pulley are massless and frictionless. A bullet of mass ( m=0.25 mathrm{kg} ) moving horizontally with velocity of ( u= ) ( 200 m / s ) penetrates through block ( A ) and comes out with a velocity of 100 ( mathrm{m} / mathrm{s} ) |
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| 213 | Assertion Use of ball bearings between two moving parts of a machine is a common practice. Reason Ball bearings reduce vibrations and provide good stability. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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| 214 | Sing 13. In the arrangement shown in rig.. , a wedged m2 = 3.45 kg is placed on a smooth horizont Small and light pulley is connected on its ton shown. A light, flexible thread passes over th Two blocks having mass m = 1.3 kg and my=1 connected at the ends of the thread. rizontal surface its top edge, as ver the pulley mo = 1.5 kg are mi CU 37° Fig. 6.293 m, is on smooth horizontal surface and my rests on inclined smooth surface of the wedge. The base length of wedge is 2 m and inclination is 37°. m, is initially near the top edge of the wedge. If the whole system is released from rest, calculate: a. velocity of wedge when my reaches its bottom b. velocity of m, at that instant (g = 10 ms) |
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| 215 | a. 9 d. 36 A block of mass m, = 1 kg and another mass m2 = 2 kg are placed together (see figure) on an inclined plane with angle of inclination e. Various values of e are given in List I. The coefficient of friction between the block m, and the plane is always zero. The coefficient of Fig. 7.368 tatic and dynamic friction between the block m, and the plane are equal to p = 0.3. In List Il expressions for the friction on the block my are given. Match the correct expression of the friction in List II with the angles given in List I, and choose the correct option. The acceleration due to gravity is denoted by g. (Useful information: tan (5.5) -0.1; tan (11.5°) – 0.2; tan (16.5°) -0.3] List I P. 0= 5° Q. 0= 10° R. 0= 15° S. @= 20° List 2 1. me sin 2. (m, + m) 8 sin e 3. umg cos e 4. um, + m)g cos e Code: (a) P-1, 2-1, R-1, S-3 (b) P-2, Q-2, R-2, S-3 (c) P-2, Q-2, R-2, S-4 (d) P-2, Q-2, R-3, S-3 (JEE Advanced, 2014) |
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| 216 | Is linear momentum of a system always conserved? |
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| 217 | A body of mass ( 2 mathrm{kg} ) is kept by pressing to a vertical wall by a force of ( 100 mathrm{N} ). the coefficient of friction between wall and body is 0.3 . then the frictional force is equal to: ( A cdot 6 N ) B. 20 N c. ( 600 mathrm{N} ) D. 700 N |
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| 218 | m uu Will U allu ulen uecrease 83. A simple pendulum consisting of a mass M attached to a string of length Lis released from rest at an angle a. A pin is located at a distance I below the pivot point. When the pendulum swings down, the string hits the pin as shown in Fig. 8.261. The maximum angle which the string makes with the vertical after hitting the pin is Pin Pino (L-1)/ м ? ! Fig. 8.261 a. cos1 Lcos.or+’ a. COS L cos a +1) L+1 b. b. cos-1 L cose+”| COS L cos a +1 L-1 |
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| 219 | f graphs are possible then, in which of the following cases external impulse must be acting on the box? ( mathbf{A} ) 3.11 ( c ) ( 0 . v ) |
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| 220 | One end of massless rope, which passes over a massless and frictionless pulley ( P ) is tied to a hook ( C ) while the other end is free. Maximum tension that the rope can bear is ( 360 N . ) With what value of maximum safe acceleration ( left(text { in } m s^{-2}right) ) can a man of ( 60 mathrm{kg} ) climb on the rope? ( A cdot 16 ) B. 6 ( c cdot 4 ) D. None of these |
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| 221 | Frictional force is nearly negligible on: A. Rough surfaces B. Semi-smooth surfaces c. Smooth surfaces D. None of these |
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| 222 | A man weighing ( 80 mathrm{kg} ) is standing at the centre of a flat boat and he is ( 20 m ) from the shore. He walks ( 8 m ) on the boat towards the shore and then halts. The boat weight 200 kg. How far is he from the shore at the end of this time? A . ( 11.2 m ) в. ( 13.8 mathrm{m} ) c. 14.3 m D. ( 15.4 mathrm{m} ) |
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| 223 | Which of the following statements about friction is true? A. Frictional force can accelerate a body B. Friction can be reduced to zero C. Frictional force is proportional to the area of contact between the two surfaces D. Sliding friction is always greater than rolling friction |
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| 224 | Value(s) of m for which the system remains at rest (pulleys and strings are ideal) is/are: ( left(boldsymbol{g}=mathbf{1 0 m} / boldsymbol{s}^{2}right) ) This question has multiple correct options ( A cdot 1 mathrm{kg} ) B. 2 kg c. ( 18 mathrm{kg} ) D. 20 kg |
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| 225 | Find the frictional force on the ( 2-mathrm{kg} ) block in the arrangement shown in Fig. |
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| 226 | Inertia means resistance to the change of state. A . True B. False |
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| 227 | When a running horse suddenly stops, the rider falls A. forwards B. backwards c. to his right D. to the horse’s right |
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| 228 | A car running with a velocity ( 72 mathrm{kmph} ) on a level road, is stopped after travelling a distance of ( 30 mathrm{m} ) after disengaging its engine ( left(g=10 m s^{-2}right) ) The coefficient of friction between the road and the tyres is. A. 0.33 B. 4. c. 0.67 D. 0.8 |
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| 229 | Friction is a/an A . self-adjusting force B. necessary evil C. important force in daily life D. all the above |
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| 230 | A block of mass ( 2 k g ) is placed on the floor. The coefficient of static friction is 0.4. Force of ( 2.8 N ) is applied on the block. The force of friction between the block and the floor is (Taken ( g= ) ( left.10 m / s^{2}right) ) ( A cdot 2.8 mathrm{N} ) B. 8 N c. 2.0 N D. zero |
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| 231 | What is the minimum value of ( F ) needed so that block begins to move upward on frictionless incline plane as shown A ( cdot M g tan left(frac{theta}{2}right) ) B. ( M g cot left(frac{theta}{2}right) ) c. ( frac{M g sin theta}{(1+sin theta)} ) D. ( M g sin left(frac{theta}{2}right) ) |
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| 232 | Due to an impulse, the change in the momentum of a body is ( 1.8 mathrm{kg} mathrm{m} mathrm{s}^{-1} . ) If the duration of the impulse is ( 0.2 mathrm{s} ) then what is the force produced in it? ( A cdot 9 N ) B. 8 N ( c cdot 7 N ) ( D cdot 6 N ) |
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| 233 | While dusting a carpet, we give a sudden jerk or beat with a stick because: A. Inertia of rest keeps the dust in its position and the dust is removed by movement of carpet away. B. Inertia of motion removes dust. C. No inertia involved in process. D. None of the above |
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| 234 | Assertion Heavier bodies fall with greater acceleration. Reason Gravitational force is stronger on heavier bodies. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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| 235 | The sparks produced during sharpening of a knife against a grinding whee leaves the rim of the wheel tangentially. This is due to which of the following? A. Inertia of rest B. Inertia of motion c. Inertia of direction D. Force applied |
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| 236 | State whether true or false. If two bodies of different masses move with the same momentum, then the heavier body will have the greater velocity A. True B. False |
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| 237 | The force ( F ) acting on a particle of mass is indicated by force-time graph shown below.The change in momentum of the particle over the time interval from zero to 8 s is |
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| 238 | Let ( F, F_{N} ) and ( f ) denote the magnitudes of the contact force, normal force and the frictional force exerted by one surface on the other kept in contact. If none of these is zero, This question has multiple correct options A ( cdot F>F_{N} ) в. ( F>f ) c. ( F_{N}>f ) D. ( F_{N}-f<F<F_{N}+f ) |
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| 239 | Two bodies have masses in the ratio 3 : 4. When a force is applied on the first body, it moves with an acceleration of ( 6 m s^{-2} . ) How much acceleration will the same force produce in the other body? A . 0 в. 4.5 ( c .5 ) D. 10 |
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| 240 | A ( 4 mathrm{m} ) long ladder weighing 25 kg rests with upper end against a smooth wall and lower end of rough ground. What should be the minimum coefficient of friction between the ground and the ladder for it to be inclined at 60 with the horizontal without slipping? (Take ( g=10 ) ( left.m s^{-2}right) ) A . 0.19 B. 0.29 ( c cdot 0.39 ) D. 0.49 |
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| 241 | While the arrow moves towards its target, the force acting on it are due to gravity and due to of air. A . gravitational force B. muscular force c. magnetic force D. frictional force |
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| 242 | State whether true or false. A ball thrown upwards in a train moving with uniform velocity returns to the thrower A. True B. False |
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| 243 | Newton’s third law of motion can be used to explain: A. Why the passengers in a bus tend to fall backward when its starts suddenly B. Swimming of a man c. Motion of a rocket D. Both (B) and (C) |
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| 244 | Assertion A rocket moves forward by pushing the surrounding air backwards. Reason It derives the necessary thrust to move forward according to Newton’s third law of motion. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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| 245 | For ordinary terrestial experiments, which of the following observers below are inertial? A. a child revolving in a “giant wheel” B. a driver in a sports car moving with a constant high speed of ( 200 mathrm{km} / mathrm{h} ) on a straight road c. the pilot of an aeroplane which is taking off D. a cyclist negotiating a sharp turn |
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| 246 | Illustration 7.6 In Fig. 7.17, an object of mass M = 10 K kept on a rough table as seen from above. Forces are applied on it as shown. Find the direction of static friction if the object does not move. (Take u= 0.4) /y 20 N 15 N Fig. 7.17 |
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| 247 | Two people push a car for 3 sec, with a combined net force of 200 N.The impulse provided to the car…. A . ( 400 mathrm{N} ) -sec B. 500 N-sec. c. 600 N-sec. D. 300 N-sec. |
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| 248 | A body of mass ( m ) slides down a smooth inclined plane having an inclination of ( 45^{circ} ) with the horizontal. It takes 4 sec to reach the bottom. If the body is placed on a similar plane having coefficient of friction ( 0.5 . ) What is the time taken for it to reach bottom? A ( .4 sqrt{2} s e c ) B. 4 sec ( mathrm{c} cdot 3 sqrt{2} mathrm{sec} ) D. ( 2 s e c ) |
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| 249 | 1 WMSUN DUNI 5. Column I gives four different situations involu blocks of mass m, and my placed in different smooth horizontal surface as shown in the figur in Column I. In each of the situations, horizontal F, and F, are applied or blocks of mass m, and respectively and also m, F, <m,F2, Match the statem statements in Column 1 with corresponding results in Column involving we (ferent ways on he figures given wontal forces me and my Column I Column II Both the blocks are connected by the massless inelastic string The magnitude of tension in the string is Both the block are connected by the massless inelastic surine The magnitude of tension in the string is 11. Fimm F2 The magnitude of normal reaction between the blocks is The magnitude of normal reaction between the blocks is Column II a. mm2 m+ m₂ (my m, m₂ mi + m₂ (my m₂) m₂ (E+F mm₂ d. mm2 my + m2 m2 mi) my + m₂) |
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| 250 | Where should be a uniform rod of length ( 10 m ) and weight ( 100 N ) and with a weight of ( 100 N ) at an extreme point be balanced? A. ( 5 mathrm{m} ) from that extreme B. ( 2.5 mathrm{m} ) from that extreme ( mathrm{c} .2 .5 mathrm{m} ) from the other extreme D. ( 5 m ) from the other extreme |
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| 251 | A ball of mass 0.5 gram is hit by battery switch giving an impulse of ( 0.075 mathrm{N} ) with what velocity does the ball move? | 11 |
| 252 | The unit of mass in SI system is and the unit of weight in ( mathrm{S} ) I system is A. kg, Newton B. m, Ampere c. seconds, Joule D. ergs, Newton |
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| 253 | Consider the situation shown in the figure. The tension in the string attached to ( 0.50 mathrm{kg} ) |
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| 254 | A block of mass ( 2 mathrm{kg} ) is resting over another block of mass 6 kg. 2 kg is connected to one end of a string fixed to a vertical wall as shown. If the coefficient of friction between the blocks is ( 0.4, ) the force required to pull out the ( 6 mathrm{kg} ) block with an acceleration of ( 1.5 mathrm{m} / mathrm{s}^{2} ) will be ( left(mathrm{g}=10 mathrm{ms}^{-2}right) ) A . 17 B. 9 N ( c cdot 8 n ) D. 1 N |
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| 255 | Mention the methods used to decrease friction |
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| 256 | Inertia of a body has direct dependence on: A. velocity B. mass c. area D. volume |
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| 257 | Match the column | 11 |
| 258 | A perfectly reflecting mirror has an area of ( 1 mathrm{cm}^{2} ). Light energy is allowed to fall on it for ( 1 h ) at the rate of ( 10 W / c m^{2} . ) The force that acts on the mirror is: В. ( 6.7 times 10^{-8} N ) ( mathrm{c} cdot 1.34 times 10^{-7} mathrm{N} ) D. 2.4 ( times 10^{-4} N ) |
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| 259 | A block of ( 1 k g ) is stopped against a wall by applying a force ( F ) perpendicular to the wall. If ( mu=0.2 ) then minimum value of ( boldsymbol{F} ) will be : ( begin{array}{ll}text { A } & text { N }end{array} ) в. ( 49 N ) ( mathbf{c} .98 N ) D. ( 490 N ) |
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| 260 | Which law of Newton is called the law of equilibrium? A. Newtons first law of motion B. Newtons second law of motion c. Newtons third law of motion D. Newtons law of gravitation |
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| 261 | Assertion On polishing the surface the friction decreases upto certain limit but increases beyond that Reason On polishing the surface, the irregularities are cut off but beyond a certain limit the surface molecules exert strong attractive forces on each other A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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| 262 | A right triangular plate ( A B C ) of mass ( m ) is free to rotate in the vertical plane about a fixed horizontal axis through ( mathbf{A} ) It is supported by a string such that the side ( A B ) is horizontal. The reaction at the support ( A ) is : ( A cdot frac{m}{3} ) B. ( frac{2 m g}{3} ) ( c cdot frac{m g}{2} ) D. ( m g ) |
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| 263 | In fig, if ( f_{1}, f_{2} ) and ( T ) are the frictional forces on ( 2 mathrm{kg} ) block, ( 3 mathrm{kg} ) block and tension in the string, respectively, the find their values. Initially before applying the forces, tension in string was zero. |
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| 264 | Complete the statement of the first law of motion. “A body at rest stays at and a body in motion stays in unless an ( _{—} ) is applied” A. Motion; Rest; External Force B. Rest; Motion; External Force c. Rest; Motion; Internal Force D. None of these |
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| 265 | A rocket of mass ( 4000 mathrm{kg} ) is set for vertical firing. How much gas must be ejected per second so that the rocket may have initial upwards acceleration of magnitude ( 19.6 ~ m / s^{2} ? ) [Exhaust speed of fuel ( =mathbf{9 8 0 m / s} ) A. ( 240 mathrm{kg} / mathrm{s} ) в. ( 80 mathrm{kg} / mathrm{s} ) c. ( 120 mathrm{kg} / mathrm{s} ) D. None |
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| 266 | Ond 3. Two blocks, with masses m, and my, are stacked as shown in Fig. 7.241 and placed on a s – Mk frictionless horizontal surface. mi There is a friction between the m two blocks. An external force of magnitude Fis applied to the Fig. 7.241 top block at an angle a below the horizontal. The coefficient of friction between m, and m2 are us and uk a. If the two blocks move together, find their acceleration. b. Calculate the maximum value of force so that blocks will move together. |
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| 267 | 75. A particle is moving along a circular path. The angular velocity, linear velocity, angular acceleration, and centripetal acceleration of the particle at any instant, respectively, are ö,v,ã, and ā, . Which of the following relations is not correct? a. Õli b. älä с. ölā d. ylä |
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| 268 | A pulley has a light rope running over it, with a ( 10 N ) weight on one side and a ( 20 N ) weight on the other. Ropes always pull with equal force on each end; this is called tension. If the masses are allowed to fall, what is the tension, ( boldsymbol{T} ) in the rope? A . ( 0 N ) В. ( 1 N<T<10 N ) ( c cdot 10 N ) D. None of these |
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| 269 | Two blocks of mass 5 kg and 10 kg are kept on a rough horizontal surface as shown in figure A force ( F ) is applied on upper block of mass 10 kg Now choose the correct statement(s) regarding the system This question has multiple correct options A. If magnitude of applied force is ( 2 mathrm{N} ) then frictional force between the blocks is also 2 N B. The acceleration of 10 kg block is 2 ( m / s^{2} ) when applied force is ( 30 mathrm{N} ) C. The minimum value of F for which 5 kg block begin to slide if coefficient of friction between blocks is changed to 0.5 is ( 45 mathrm{N} ) D. 5 kg block will never move on the ground for any value of F if coefficient of friction between blocks is 0.1 and between block and surface is 0.3 |
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| 270 | Which of the following statements is incorrect? A. Friction acts on a ball rolling along the ground. B. Friction acts on a boat moving on water. C. Friction acts on a bicycle moving on a road. D. Friction does not act on a ball moving through air |
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| 271 | Assertion The ratio of inertial mass to gravitational mass is equal to one. Reason The inertial mass and gravitational mass of a body are equivalent. |
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| 272 | A uniform rod of length ( L ) rests against a smooth wall as shown in figure. Find the friction coefficient between the ground and the lower end if the minimum angle that the rod can make with the horizontal is ( theta ) A ( cdot frac{L cos ^{2} theta sin theta}{2 h-l cos theta sin ^{2} theta} ) B. ( frac{L cos theta sin ^{2} theta}{2 h-l operatorname{cs} theta sin ^{2} theta} ) c. ( frac{L cos ^{2} theta sin theta}{2 h-l cos ^{2} theta sin theta} ) D. ( frac{L cos theta sin ^{2} theta}{2 h-l cos ^{2} theta sin theta} ) |
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| 273 | A railway carriage has its centre of gravity at a height of ( 1 m ) above the rails which are ( 1.5 m ) apart.The maximum safe speed at which it could travel round an unbanked curve of radius ( 100 m ) is ( mathbf{A} cdot 12 m / s ) в. ( 18 mathrm{m} / mathrm{s} ) c. ( 22 m / s ) D. ( 27 m / s ) |
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| 274 | A solid sphere, a hollow sphere and a solid cylinder, all having equal mass and radius, are placed at the top of an incline and released. The friction coefficients between the objects and the incline are equal and but not sufficient to allow pure rolling. Greastest time will be taken in reaching the bottom by A. The solid sphere B. The hollow sphere c. The solid cylinder D. All will take same time |
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| 275 | Consider the situation shown in the figure. Calculate the acceleration of the ( 1.0 mathrm{kg} ) blocks |
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| 276 | A cyclist is moving on a circular track of radius ( 80 m ) with a velocity of ( 72 k m / h r . ) He has to lean from he vertical approximately through an angle- ( mathbf{A} cdot tan ^{-1}(1 / 4) ) B cdot ( tan ^{-1}(1) ) c. ( tan ^{-1}(1 / 2) ) ( D cdot tan ^{-1}(2) ) |
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| 277 | When a bus suddenly takes a turn, the passengers are thrown outwards because of A. Inertia of motion B. Acceleration of motion c. speed of motion D. Both (b) and (c) |
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| 278 | A pendulum bob is held stationary by a horizontal force H. The three forces acting on the bob are shown in the diagram. The tension in the string of the pendulum is T. The weight of the pendulum bob is W.The string is held at an angle of ( 30^{circ} ) to the vertical. Which statement is correct? A. ( H=T cos 30 ) B. ( T=H sin 30 ) c. ( W=T sin 30 ) D. ( W=T cos 30 ) |
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| 279 | Illustration 7.46 A small block is connected to one end of two identical massless strings of length 16- cm 600 1 T each with their other ends fixed to a vertical rod. If the ratio of tensions T/T, is 4:1, then what will be the angular velocity of the block? Take g=9.8 ms. Fig. 7.159 |
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| 280 | Assertion A horse has to pull a cart harder during the first few steps of his motion. Reason The first few steps are always difficult. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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| 281 | The tension in the string is: A. 600 N B. 80 N c. 1200 N D. ( 800 mathrm{N} ) |
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| 282 | A body of mass ( 5 mathrm{kg} ) is acted upon by two perpendicular forces ( 8 mathrm{N} ) and ( 6 mathrm{N} ) Given the magnitude and direction of the acceleration of the body. | 11 |
| 283 | A body of mass ( m=1 k g ) is moving in a medium and experiences a fractions force ( F=-k v, ) where ( v ) is the speed of the body. The initial speed is ( v_{0}= ) ( 10 m s^{-1} ) and after ( , 10 s ) its energy becomes half of initial energy. Then, the value of ( k ) is A. ( 10 ln sqrt{2} ) 2 ( ln log 2 ) B. ( ln sqrt{2} ) ( c cdot frac{ln 2}{20} ) D. ( 10 ln 2 ) E . ( ln 2 ) |
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| 284 | The statement ‘Acceleration is zero if and only if the net force is zero’ is valid in A. Non-inertial frames B. Inertial frames C. Both in an inertial frames and non-inertial frames D. Neither inertial frames nor non-inertial frames |
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| 285 | A truck of mass ( 500 k g ) moves from the rest at the top of a section of track ( 400 m ) long and ( 30 m ) high, as shown. The frictional force acting on the truck is ( 250 N ) throughout its journey. What is the final speed of the truck? |
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| 286 | From the following 3 solids of the same shape and same volume which one has the highest inertia? A. steel B. Woodd c. Aluminium D. None of the above |
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| 287 | A force ( F ) is applied horizontally on a cylinder in the line of centre as shown in the figure. The cylinder is on a rough surface of coefficient of friction ( mu . ) The direction of the friction force acting on the cylinder will be A. In the direction of ( F ) B. zero c. In the opposite direction of ( F ) D. Cannot be ascertained |
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| 288 | If the gravitational force of earth suddenly disappears, then which of the following is correct? A. weight of the body is zero B. Mass of the body is zero c. Both mass and weight becomes zero D. Neither the weight nor the mass is zero. |
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| 289 | The motion of a block sliding down a frictionless ramp can be described as motion with A. A constant speed, independent of the slope of the ramp B. A constant speed that depends on the slope of the ramp c. An acceleration which increases as the block slides D. A constant acceleration less than ( 10 mathrm{m} / mathrm{s}^{2} ) E. A constant acceleration greater than ( 10 mathrm{m} / mathrm{s}^{2} ) |
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| 290 | A cricket ball of mass ( 500 mathrm{g} ) is moving with speed of ( 36 k m h^{-1} . ) It is reflected back with the same speed. What is the impulse applied on it? A. ( 20 mathrm{Kg} mathrm{m} / mathrm{s} ) B. ( 10 mathrm{kg} mathrm{m} / mathrm{s} ) c. ( 5 mathrm{kg} mathrm{m} / mathrm{s} ) D. none of the above |
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| 291 | A machine gun fires a bullet of mass ( 40 g ) with a velocity ( 1200 m / s . ) The man holding it can exert a maximum force of ( 144 N ) on the gun. How many bullets can be fired per second at the most? A. Only one B. Three c. can fire any number of bullets D. ( 144 times 48 ) |
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| 292 | Assertion We can live very happily if the friction is not present in nature. Reason Aeroplane shape is stream lined to reduce the effort of frictional force. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
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| 293 | A canon after firing recoils due to newton’s third law of motion. A . True B. False |
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| 294 | Friction is a force that opposes motion. A. True B. False c. Ambiguous D. Data insufficient |
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| 295 | A ball of mass ( m ) at rest receives an impulse ( I_{1} ) in the direction of north. After some time, it received another impulse ( I_{2} ) in the direction of south. The final kinetic energy of the ball is A ( cdot frac{left(I_{1}+I_{2}right)^{2}}{2 m} ) в. ( frac{left(I_{1}-I_{2}right)^{2}}{2 m} ) c. ( frac{I_{1}^{2}+I_{2}^{2}}{2 m} ) D. ( frac{I_{1}^{2}-I_{2}^{2}}{2 m} ) |
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| 296 | Determine the force acting on a body if the velocity of the body is changed from ( 5 m s^{-1} ) to10 ( m s^{-1} ) in 2 s. The density and the volume of the object are ( mathbf{5 0 0 0 k g} boldsymbol{m}^{-3} boldsymbol{a n d} quad mathbf{0 . 0 0 5} boldsymbol{m}^{3} ) ( mathbf{A} cdot 100 mathrm{N} ) B. 65.5 N c. ( 32.5 mathrm{N} ) D. 62.5 N |
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| 297 | A wheel as the angular acceleration of ( 3.0 mathrm{rad} / mathrm{sec}^{2} ) and initial angular speed of 2.00 rad/sec. In a time of 2 sec, it has rotated through an angle (in radians) of ( A cdot 4 ) B. 6 c. 10 D. 12 |
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| 298 | Match the following List I List 1 a. frictional force ( quad ) e. reduction of friction b. rolling friction f. causes wear and tear c. ball bearing less than kinetic friction g. d. trading of surface ( quad ) h. increase of friction The correct match is ( mathbf{A} cdot a rightarrow i ; b rightarrow e ; c rightarrow h ; d rightarrow f ) B ( cdot a rightarrow f ; b rightarrow f ; c rightarrow e ; d rightarrow g ) ( mathbf{c} cdot a rightarrow f ; b rightarrow g ; c rightarrow e ; d rightarrow h ) D ( . a rightarrow i ; b rightarrow f ; c rightarrow h ; d rightarrow e ) |
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| 299 | What is weight? | 11 |
| 300 | We know that friction depends upon mass of the body. When we roll down an iron ball and a football on the ground, which ball will travel more distance? Why? |
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| 301 | What do we call the gravitational force between the earth and an object? | 11 |
| 302 | A decoration, of mass ( M, ) is suspended by a string from the ceiling inside an elevator. The elevator is traveling upward at a constant speed. The tension in the string is A. Equal to ( M g ) B. Less than ( M g ) c. Greater than ( M g ) D. Impossible to tell without knowing the speed |
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| 303 | A car of mass ( m ) is taking a circular turn of radius ‘ ( r^{prime} ) on a fictional level road with a speed ( v . ) In order that the car does not skid A ( cdot frac{m v^{2}}{r} geq mu m g ) B . ( frac{m v^{2}}{r} leq mu m g ) c. ( frac{m v^{2}}{r}=mu m g ) D. ( frac{v}{r}=mu m g ) |
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| 304 | An object is placed on the surface of a smooth inclined plane of inclination ( boldsymbol{theta} ). It takes time ( t ) to reach the bottom. If the same object is allowed to slide down a rough inclined plane of same inclination ( theta ), it takes times nth to reach the bottom where ( n ) number greater than ( 1 . ) The coefficient of friction ( mu ) is given by: A ( cdot mu=tan thetaleft(1-1 / n^{2}right) ) B cdot ( mu=cot thetaleft(1-1 / n^{2}right) ) c. ( mu=tan thetaleft(1-1 / n^{2}right)^{1 / 2} ) D. ( mu=cot thetaleft(1-1 / n^{2}right)^{1 / 2} ) |
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| 305 | Block A of weight ( 100 mathrm{N} ) reset on a frictionless inclined plane of slope angle ( 430^{0} ) as shown in the figure. A flexible cord attached to A passes over a frictionless pulley and is connected to block B of weight W. Find the weight ( mathbf{W} ) of which the system is in equilibrium. A . 25 N в. 50 N ( c .75 mathrm{N} ) D. 100 N |
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| 306 | In the given arrangement the maximum value of ( F ) for which there is no relative motion between the blocks A ( cdot mu m_{1} S ) В. ( muleft(m_{1}+m_{2}right) ) в ( c ) [ mu m_{1} gleft(frac{m_{1}}{m_{2}}+1right) ] D. zero |
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| 307 | Which of the following has more inertia. A rubber ball or a stone of the same size? A. rubber ball B. stone c. both have same intertic D. cannot be determined |
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| 308 | surface under the influence of a force ( boldsymbol{P} ) of the same magnitude in all the three cases. CoOefficient of friction is the same between each block and the ground. What possible relation holds between the magnitude of normal reaction and friction forces? (Assume that the block do not overturn about edge.) Here, ( boldsymbol{f}_{A}, boldsymbol{f}_{B} ) and ( boldsymbol{f}_{C} ) are frictional forces and ( N_{A}, N_{B} ) and ( N_{C} ) are reactions. This question has multiple correct options |
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| 309 | A small sphere of mass ( m=2 k g ) moving with a velocity ( bar{u}=hat{4} i-7 hat{j} m / s ) collides with a smooth wall and returns with a velocity ( bar{v}=hat{i}-3 hat{j} m / s . ) The magnitude of the impulse received by the ball is ( mathbf{A} cdot 5 k g m s^{-1} ) В. ( 10 k g m s^{-1} ) c. ( 20 mathrm{kgms}^{-1} ) D. ( 15 k g m s^{-1} ) |
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| 310 | A streamlined body: A. increases friction B. reduces friction C . decreases weight D. increases weight |
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| 311 | A bullet of mass ( 40 g ) is fired from a gun of mass ( 10 mathrm{kg} ). If velocity of bullet is ( 400 m / s, ) then the recoil velocity of the gun will be A. ( 1.6 mathrm{m} / mathrm{s} ) in the direction of the bullet B. ( 1.6 mathrm{m} / mathrm{s} ) opposite to the direction of the bullet c. ( 1.8 m / s ) in the direction of the bullet D. ( 1.8 mathrm{m} / mathrm{s} ) opposite to the direction of the bullet |
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| 312 | When a tree with a flexible stem is shaken vigorously,its fruits and leaves fall own.This phenomenon can be explained by making use of A. Newton’s first law of motion B. Newton’s second law of motion c. Newton’s third law of motion D. Law of conservation of momentum |
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| 313 | A bullet of mass ( m ) is fired from the gun, the acceleration of the bullet is A. greater than the acceleration of the gun B. equal to the acceleration of the gun C. equal but opposite to the acceleration of the gun D. directly proportional to the mass of the bullet E. inversely proportional to the force of the bullet |
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| 314 | Unevenness in the surfaces of the moving body and the surface on which it moves causes: A . Gravitational force B. Frictional force c. centripetal force D. Centrifugal force |
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| 315 | When one body rolls over the surface of another body, which kind of friction does it produce? A. Static B. Rolling c. Fluid D. sliding |
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| 316 | It is difficult for a fireman to hold a hose pipe which ejects large amounts of water at high velocity due to : A. Newton’s first law B. Newton’s second law c. Newton’s third law D. Newton’s gravitation law |
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| 317 | The coefficient of limiting friction between the surfaces of contact is the ratio of the ( ldots ). friction to the normal reaction A. Limting B. sliding c. rolling D. any of these |
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| 318 | A car travelling ( 20 m / s ) enters into a unbanked curve with a radius of ( 25 m ) If the coefficient of friction between the tires and the road is ( 0.75, ) what is the magnitude of the change in velocity of the car if the car is going to stay in its lane? ( mathbf{A} cdot Delta v=3.20 m / s ) B. ( Delta v=6.40 m / s ) c. ( Delta v=12.8 m / s ) D. ( Delta v=13.6 mathrm{m} / mathrm{s} ) E ( . Delta v=26.4 m / s ) |
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| 319 | Particles of masses ( m_{1} ) and ( m_{2} ) are at a fixed distance apart. If the gravitational field strength at ( m_{1} ) and ( m_{2} ) are ( vec{I}_{1} ) and ( vec{I}_{2} ) respectively. Then ( mathbf{A} cdot m_{1} vec{I}_{1}-m_{2} vec{I}_{2}=0 ) В . ( m_{1} vec{I}_{2}+m_{1} vec{I}_{2}=0 ) C ( cdot m_{2} vec{I}_{2}-m_{2} vec{I}_{2}=0 ) D . ( m_{1} vec{I}_{2}-m_{2} vec{I}_{1}=0 ) |
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| 320 | A block of mass ( 60 mathrm{kg} ) just slides over a horizontal distance of ( 0.9 mathrm{m} ). If the coefficient of friction between their surface is 0.15 then work done against friction will be B. 97.54 J c. 105.25 D. None of these |
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| 321 | 38. If block A is moving with an acceleration of 5 ms, the acceleration of B w.r.t ground is 5 ms-2 Fig. 6.321 b. 52 ms 2 d. 10 ms-2 a. 5 ms-2 c. 515 ms-2 |
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| 322 | A cricket ball of mass 500 gm strikes a bat normally with a velocity ( 30 mathrm{m} / mathrm{s} ) and rebounds with a velocity ( 20 mathrm{m} / mathrm{s} ) in the opposite direction. The impulse of the force exerted by the ball on the bat is: A. ( 0.5 mathrm{N} . ) B. 1.0 N.s c. 25 N. D. 50 N.s |
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| 323 | ( mathbf{A} ) ( 60 mathrm{kg} ) mass is pushed with a enough force to start it moving and the same force is continued to act afterward. If the coefficient of static friction and sliding friction are 0.5 and 0.4 respectively, then the acceleration of the body will be A ( cdot 1 mathrm{ms}^{-2} ) B. ( 3.9 mathrm{ms}^{-2} ) c. ( 4.9 mathrm{ms}^{-2} ) D. ( 6 m s^{-2} ) |
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| 324 | In the given figure a block of weight ( 10 N ) is resting on a horizontal surface. The coefficient of static friction between the block and the surface is ( mu_{s}=0.4 . ) A force of ( 3.5 N ) will keep the block in uniform motion, once it has been set in motion. A horizontal force of ( mathbf{3} N ) is applied to the block, then the block will A. move over the surface with constant velocity B. move having accelerated motion over the surface. c. will not move. D. first it will move with a constant velocity for some time and then it will have an accelerated motion |
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| 325 | A uniform beam of ( 2 m ) is fixed to a wall and loaded by the forces shown above. Given that the beam is at equilibrium, calculate force ( F ) A ( .2 N ) B. ( 4 N ) ( c cdot 7 N ) D. ( 8 N ) |
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| 326 | A good lubricant should be highly A. viscous and volatile B. non-viscous and non-volatile c. viscous and non-volatile D. transparent |
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| 327 | Tyres have treads to friction.fill in the bank. A. increase B. decrease c. neglect D. overcome |
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| 328 | Two particles of masses ( m_{1} ) and ( m_{2} ) are moving velocities ( vec{V}_{1} ) and ( vec{V}_{2} ) Momentum of the particle of mass ( m_{1} ) with respect to center of mass is A. zero B. ( frac{m_{1} m_{2}}{m_{1}+m_{2}}left(vec{V}_{1}-vec{V}_{2}right) ) c. ( frac{m_{2}}{m_{1}+m_{2}}left(vec{V}_{1}-vec{V}_{2}right) ) D. None of these |
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| 329 | The velocity of the block at the midpoint between ( B ) to ( C ) will be : A. ( frac{sqrt{2 g h}}{2} ) B. ( sqrt{2 g h} ) ( mathbf{c} cdot sqrt{g h} ) ( D cdot frac{sqrt{g h}}{2} ) |
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| 330 | A body of mass ( 2 k g ) is lying on a floor The coefficient of static friction is 0.54 What will be the value of frictional force if the force is ( 2.8 N ) and ( g=10 m s^{-2} ? ) A . zero в. ( 2 N ) ( c .2 .8 N ) D. ( 8 N ) |
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| 331 | of the rod is ( M ) ad mass of bead is ( m ) and ( M>m . ) The bead slides with some friction. The mass of the pulley and friction in its axle are negligible. At the initial moment the bead was located opposite the lower end. If set free both the bodies move with constant accelerations. The frictional force between the bead and the thread so that ( t ) second after release ball reaches the upper end of the rod is given as ( boldsymbol{F}_{boldsymbol{f}}= ) ( frac{boldsymbol{x} boldsymbol{m} boldsymbol{M} boldsymbol{l}}{(boldsymbol{M}-boldsymbol{m}) boldsymbol{t}^{2}} . ) Find ( boldsymbol{x}, ) Length of the rod is ( l ) |
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| 332 | A train runs along an unbanked circular track of radius ( 30 m ) at a speed of ( mathbf{5 4 k m / h .} ) The mass of the train is ( 10^{6} k g ) What provides the centripetal force required for this purpose-the engine or the rails? What is the angle of banking required to prevent wearing out of the rail? |
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| 333 | A tennis ball and an iron ball is thrown towards us with the same velocity. Then, the tennis ball is easy to catch as compared to an iron ball. A. True B. False |
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| 334 | A man is walking from east to west on a level rough surface. The force of friction on the man is directed: A. from west to east B. from east to west c. along the north D. along the west |
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| 335 | A block slides down on an incline of angle ( 30^{circ} ) with an acceleration ( frac{g}{4} . ) Find the coefficient of kinetic friction. A ( cdot frac{1}{2 sqrt{2}} ) B. 0.6 c. ( frac{1}{2 sqrt{3}} ) D. ( frac{1}{sqrt{2}} ) |
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| 336 | The brakes of a car moving at ( 20 m / s ) along a horizontal road are suddenly applied and it comes to rest after travelling some distance. If the coefficient of friction between the tyres and the road is 0.90 and it is assumed that all four tyres behave identically, find the shortest distance the car would travel before coming to a stop. A. ( 2.22 m ) В. ( 11.35 m ) c. ( 22.2 m ) D. ( 4.54 m ) |
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| 337 | Abo Illustration 6.2 on 6.2 A body of mass m= 1 kg falls from a height h=20 m from the ground level. What is the magnitude of total change in momentum of the body before it strikes the ground? h What is the corresponding average force experienced by it? (8 = 10m s |
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| 338 | When a horse pulls a wagon, the force that causes the horse to move forward is the force: A. the ground exerts on it B. it exerts on the ground c. the wagon exerts on it D. it exerts on the wagon |
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| 339 | If no force acts on a body, then what will happen to it? A. It does not change its shape. B. It continues to move but with less speed. c. It changes its direction. D. It can either remain at rest or continue to move in a straight line. |
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| 340 | Block B rests on block A. Block A rests on a horizontal surface ( C ) which is frictionless. There is friction between ( mathbf{A} ) and B. If B is pulled to the right, then: A. B moves forward and A to the left B. B only moves to the left c. B does not move D. A and B move to right however their acceleration can be different. |
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| 341 | Calculate the momentum of a bullet of ( 25 g ) when it is fired from a gun with a velocity of ( 100 m / s ) A. 20 kg ( m / s ) в. ( 2500 mathrm{kg} mathrm{m} / mathrm{s} ) c. ( 2.5 mathrm{kg} mathrm{m} / mathrm{s} ) D. None |
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| 342 | If a ball is thrown upwards from the Surface of earth: A. The earth remains stationary while the ball moves upwards B. The ball remains stationary while the earth moves downwards C. The ball and earth both move towards each other D. The ball and earth both move away from each other |
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| 343 | Which of the following statements are true? This question has multiple correct options A. When the mass of a body is doubled then the momentum of a body is also doubled, provided the body maintains the same velocity. B. We feel pain in the hand on hitting the wall, this is a consequence of Newton’s third law of motion. C. A table cloth can be pulled from a table without dislodging the dishes. This is due to inertia of rest. D. Momentum is a vector quantity. |
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| 344 | 25. In the system shown all the surfaces are frictionless while pulley and string are massless. The mass of block A is 2m and that of block B is m. The acceleration of block B immediately after system is released from rest is Fig. 6.345 a. g/ 2 c. g/3 m b . d. none of these maiale avitame and the acceleration 11 |
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| 345 | What is the maximum value of the force F such that the block shown in the arrangement, does not move? A. 20N B. 10N ( c cdot ) 12N D. 15N |
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| 346 | To test the quality of a tennis ball, you drop it onto the floor from a height of ( 4.00 mathrm{m} . ) It rebounds to a height of ( 2.00 mathrm{m} ) If the ball is in contact with the floor for ( 12.0 mathrm{ms}, ) what is its average acceleration during that contact? Take ( boldsymbol{g}=mathbf{9} mathbf{8} boldsymbol{m} / boldsymbol{s}^{2} ) |
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| 347 | A ball of mass ‘m’ is projected from the ground with a speed ‘u’ at an angle ‘ ( alpha ) with the horizontal. The magnitude of the change in momentum of the ball over a time interval from begining till it strikes the ground again is A ( cdot frac{m u sin alpha}{2} ) B. ( 2 m u cos alpha ) c. ( frac{m u cos alpha}{2} ) D. ( 2 m u sin alpha ) |
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| 348 | is a force that resists the movement of a solid object through a fluid. A. Thrust B. Magnetic force C. Fluid friction D. None of these |
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| 349 | A body of mass m moving with a velocity v is acted upon by a force. Write expression for change in momentum when ( boldsymbol{v} rightarrow boldsymbol{c} ) ( mathbf{A} cdot m Delta v ) B . ( Delta(m v) ) c. ( v Delta(m) ) D. ( m v ) |
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| 350 | A car of mass ( mathrm{m} ) is moving on a level circular track of radius R. If ( mu_{s} ) represents the static friction between the road and tyres of the car, the maximum speed of the car in circular motion is given by: A ( cdot sqrt{R g / mu_{s}} ) B . ( sqrt{m R g / mu_{s}} ) ( mathrm{c} cdot sqrt{mu_{s} R g} ) D. ( sqrt{mu_{s} m R g} ) |
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| 351 | heat is produced whenever work is done against friction A. True B. False |
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| 352 | 20 3 kg в 6 kg 8. Two blocks A and B of masses 6 kg and 3 kg rest on a smooth horizontal surface as shown in the Fig. 7.264. If coefficient of friction between A and B is 0.4, the maximum horizontal force which can make them move without separation is a. 72 N b. 40 N c. 36 N Fig. 7.264 d. 20 N |
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| 353 | are connected together by a light spring of stiffness ( k . ) The system is lying on a smooth horizontal surface with the block ( A ) in contact with a fixed vertical wall as shown in the figure. The block ( boldsymbol{B} ) is pressed towards the wall by a distance ( x_{0} ) and then released. There is no friction anywhere. If spring takes time ( Delta t ) to acquire its natural length then average force on the block ( A ) by the wall is : A. Zero B. ( frac{sqrt{2 m k}}{Delta t} x_{0} ) c. ( frac{sqrt{m k}}{Delta t} x_{0} ) D. ( frac{sqrt{3 m k}}{Delta t} x_{0} ) |
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| 354 | Which of the following Newton’s law(s) is/are not applicable in non-inertial reference frame. A. Newton’s first law B. Newton’s second law c. Newton’s third law D. All of these |
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| 355 | A force of ( 98 mathrm{N} ) is just able to move a block of mass ( 20 mathrm{kg} ) on a rough horizontal surface. Calculate the coefficient of friction and angle of friction. ( g=9.8 mathrm{m} / mathrm{s}^{-2} ) |
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| 356 | Illustration 7.49 A turn of radius 20 m is banked for the vehicles going at a speed of 36 kmh-. If the coefficient of static friction between the road and the tyre is 0.4, what are the possible speeds of a vehicle so that it neither slips down nor skids up? |
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| 357 | A machine gun fires a bullet of mass ( 40 g ) with a velocity ( 1200 m s^{-1} ). The man holding it can exert a maximum force of ( 144 N ) on the gun. How many bullets can he fire per second at the most? A .2 B. 4 ( c . ) D. 3 |
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| 358 | A horse tied to a cart is standing stationary on road. Which of the following statement is CORRECT? A. Horse is applying force on the carttt B. Cart is applying force on the horse c. Force applied by the horse is balanced by the force applied by the cart D. No forward force is being applied by the horse or the cart |
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| 359 | wards, then the 35. If the acceleration of block A is a rightwards, the acceleration of block B will be 4a a. , upwards , upwards 3a va upwards d. 49, upwards |
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| 360 | A block of mass 10 kg placed on rough horizontal surface having coefficient of friction ( =0.5, ) if a horizontal force of ( 100 mathrm{N} ) acting on it then acceleration of the block will be : ( A cdot 10 mathrm{m} / mathrm{s}^{2} ) B. ( 5 mathrm{m} / mathrm{s}^{2} ) ( mathrm{c} cdot 15 mathrm{m} / mathrm{s}^{2} ) D. ( 0.5 mathrm{m} / mathrm{s}^{2} ) |
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| 361 | Force is directly proportional to A. Rate of change in distance B. Rate of change in velocity C. Momentum D. Rate of change in momentum |
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| 362 | State whether true or false. The linear momentum of a body at rest is zero. A. True B. False |
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| 363 | Mark correct option or options. A. The body of greater mass needs more forces to move due to more inertia B. Force versus time graph gives impulse C. Microscopic area of contact is about ( 10^{-4} ) times actual area of the contact D. All of the above |
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| 364 | The momentum of a moving particle is vectorially given as ( overrightarrow{boldsymbol{p}}=boldsymbol{p}_{0}(cos boldsymbol{t} hat{boldsymbol{i}}+ ) ( sin t hat{j}), ) where ( t ) stands for time. choose the correct option: A. The applied force is constant B. The momentum is constant C. The applied force always remains perpendicular to the momentum. D. The applied force is always parallel to the momentum |
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| 365 | A motorcyclist executes a horizontal loop at a speed of ( 65 k m / h ) while himself making an angle of ( 12^{circ} ) with the horizontal. What is the radius of the ( operatorname{loop} ?(operatorname{in} m) ) ( mathbf{A} cdot 123.6 ) B. 156.6 c. 156.3 D. 174.3 |
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| 366 | Inside a railway car a plumb bob (a heavy mass suspended by a thread) is suspended from the roof and a helium filled balloon is tied by a string to the floor of the car. When the railway car accelerates to the right, then A. Both the plumb bob and balloon move to the left B. Both the plumb bob and balloon move to the right c. Plumb bob moves to the left and the balloon moves to the right D. Plumb bob moves to the right and the balloon moves to the left |
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| 367 | A curved road is ( 7.5 ~ m ) wide and its outer edge is raised by 1.5 m over the inner edge. The radius of curvature is ( 50 m . ) For what speed of the car is this road suited? ( left(boldsymbol{g}=mathbf{1 0 m} / boldsymbol{s}^{2}right) ) A. ( 5 mathrm{m} / mathrm{s} ) в. ( 10 mathrm{m} / mathrm{s} ) c. ( 15 mathrm{m} / mathrm{s} ) D. 20 ( m / s ) |
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| 368 | Three identical bodies, each of mass ( m ) are pushed by a force ( boldsymbol{F} ) on a frictionless table a shown in the figure. Then: A. Net force on ( X ) is ( F ) B C. Force applied by ( Y ) on ( Z ) is equal net force on ( X ) D. Net force on ( Y ) is equal to zero |
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| 369 | A body of mass M collides with a wall with velocity ( V ) and rebounds with the same speed. Its change in momentum is equal to : A. zero в. му c. гму D. 3MV |
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| 370 | Explain rocket propulsion. | 11 |
| 371 | A rocket works on the which law of motion? A. Newton’s first law B. Newton’s second law c. Newton’s third law D. None of these |
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| 372 | An object is thrown vertically upward with a non zero velocity. If gravity is turned off at the instant the object reaches the maximum height, what will happen? A. The object continues to move in a straight line B. The object will be at rest C. The object falls back with uniform velocity D. The object falls back with uniform acceleration |
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| 373 | What is the momentum of an object of mass ( m, ) moving with a velocity ( v ? ) A ( cdot(m v)^{2} ) a) ( ^{infty} ) B. ( m v^{2} ) c. ( 1 / 2 m v^{2} ) D. ( m v ) |
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| 374 | Identify the correct statement. A. Static friction depends on the area of contact. B. Kinetic friction depends on the area of contact. C. Coefficient of static friction does not depend on the surface in contact. D. Coefficient of kinetic friction is less than the coefficient of the static friction. |
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| 375 | A ball moving with a momentum of 5kgm/s strikes against a wall at an angle of ( 45^{circ} ) and is reflected at the same angle. The change in momentum will be ( (mathrm{kg}-mathrm{m} / mathrm{s}): ) A . 7.07 B. 14.14 c. 8.00 D. 7.5 |
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| 376 | A car is traveling in plane curved road of radius 125 m. If the coefficient of friction between the tyres and road is 0.5 and ( g=10 m / s^{2} . ) The maximum speed to avoid skidding is: A . ( 50 mathrm{m} / mathrm{s} ) в. ( 25 mathrm{m} / mathrm{s} ) c. ( 20 m / s ) D. 10 ( m / s ) |
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| 377 | A flat curve on a highway has a radius of curvature 400 m. A car goes around a curve at a speed of ( 32 m / s . ) What is the minimum value of coefficient of friction that will prevent the car from sliding? ( boldsymbol{g}=mathbf{9 . 8} boldsymbol{m} / boldsymbol{s}^{2} boldsymbol{)} ) |
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| 378 | A particle of mass ( m ) is made to move with uniform speed ( v_{0} ) along the perimeter of a regular hexagon, inscribed in a circle of radius ( boldsymbol{R} ). The magnitude of impulse applied at each corner of the hexagon is: ( mathbf{A} cdot 2 m v_{0} sin pi / 6 ) в. ( m v_{0} sin pi / 6 ) c. ( m v_{0} sin pi / 3 ) D. ( 2 m v_{0} sin pi / 3 ) |
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| 379 | ration of A 6. What is the magnitude of relative acceleration with respect to B just after both have lost contact ground. a. 15 ms. b. 5 ms. c. 20 ms d. 10 mg-1 |
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| 380 | A cyclist riding the bicycle at a speed of ( 14 sqrt{3} m s^{-1}, ) takes a turn around a circular of radius ( 20 sqrt{3} m, ) without skidding. Given ( g=9.8 m s^{-2}, ) what is his inclination to the vertical? A . ( 30^{circ} ) B. ( 90^{circ} ) ( c cdot 45^{circ} ) D. ( 60^{circ} ) |
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| 381 | The masses of ( 10 k g ) and ( 20 k g ) respectively are connected by a massless spring. A force of ( 200 N ) acts on the ( 20 k g ) mass. At the instant shown the ( 10 k g ) mass has an acceleration of ( 12 m s^{-2}, ) what is the acceleration of ( 20 k g ) mass ( ? ) A ( cdot 12 m s^{-2} ) B. ( 4 m s^{-2} ) ( mathrm{c} cdot 10 mathrm{ms}^{-2} ) D. ( 20 m s^{-2} ) |
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| 382 | A rod of length of ( 1 mathrm{m} ) is attached to the string at its mid point. A 6 kg mass is attached to end of the rod and another mass ( mathrm{M} ) is hung at a distance of ( 30 mathrm{cm} ) from the center of the rod as shown in the figure. Assume mass of rod is negligible. Find out the value of ( mathrm{M} ). ( A cdot 3 mathrm{kg} ) B. ( 5 mathrm{kg} ) ( c cdot 6 mathrm{kg} ) D. ( 10 mathrm{kg} ) E. 30 kg |
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| 383 | A block of mass ( 0.1 k g ) is held against a wall by applying a horizontal force on ( mathbf{5} N ) on it. If ( mu_{s} ) between the wall and the block is 0.5 the magnitude of the frictional force acting on the block is : A . ( 0.98 N ) B. ( 0.49 N ) c. ( 4.9 N ) D. ( 2.5 N ) |
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| 384 | A uniform metre scale balances horizontally on a knife edge placed at ( 55 mathrm{cm} ) mark. When a mass of ( 25 g ) is supported from one end, then the mass of the scale is: A. ( 200 g ) в. ( 225 g ) c. ( 350 g ) D. ( 275 g ) |
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| 385 | You are designing an elevator for a hospital. The force exerted on a passenger by the floor of the elevator is not to exceed 1.60 times the passenger’s weight. The elevator accelerates upward with constant acceleration for a distance of 3.0 m and then starts to slow down. What is the maximum speed (in ms) of the elevator? |
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| 386 | A force of 50 dynes is acted on a body of mass ( 5 g ) which is at rest for an interval of ( 3 s, ) then impulse is: A. ( 0.15 times 10^{-13} mathrm{Ns} ) В. ( 0.98 times 10^{-3} N s ) ( mathrm{c} cdot 1.5 times 10^{-3} mathrm{Ns} ) D. ( 2.5 times 10^{-3} N s ) |
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| 387 | A mass m starting from A reaches B of frictionless track. On reaching B, it pushes the track with a force equal to ( x ) times its weight, then the applicable relation is : A ( n=frac{(5-x)}{2} ) в. ( h=frac{x}{2} R ) ( c cdot h=R ) ‘ ( h=left(frac{x+1}{2}right) R ) |
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| 388 | Illustration 6.20 A homogeneous flexible rope rests on a wedge whose side edges make angles a and ß with the horizontal (refer Fig. 6.60). The central part of the rope lies on the upper rib C of the wedge. With what acceleration should the wedge be pulled to the left along the horizontal plane in order to prevent the displacement of the rope with respect to the wedge? [Consider all surfaces to be smooth] Fig. 6.60 |
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| 389 | toppr Q Type your question_ What minimum force must be applied on the ( 10 g ) block to keep it on the table? What will be the tension in the cord under this condition? What will be the acceleration of the system and the tension in the cord when the force is withdrawn? ( left(g=9.8 m s^{-2}right) ) |
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| 390 | What measures are taken to reduce fluid friction in aeroplanes? A. Optimum speed is maintained with respect to the air B. Metals are choosen in a way to make the aeroplane lighter with smoother surface C. Streamlined body inspired by birds D. All of the above |
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| 391 | A loaded transport truck with a mass of ( 38000 mathrm{kg} ) is travelling at ( 1.20 mathrm{m} / mathrm{s} ). What will be the velocity of a ( 1400 mathrm{kg} ) car if it has the same momentum? A. ( 32.57 mathrm{m} / mathrm{s} ) B. 30 ( mathrm{m} / mathrm{s} ) ( c cdot 15 m / s ) D. 32.67 ( mathrm{m} / mathrm{s} ) |
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| 392 | 14 12 connected by a string which passes over a frictional pulley. If ( mathrm{M}_{1}, mathrm{M}_{2} ) and the table are frictionless, the acceleration of the masses would be ( mathbf{A} cdot frac{M_{1} g}{M_{1}+M_{2}} ) B. ( frac{M_{1}+M_{2}}{M_{1} g} ) c. ( frac{M_{2} g}{M_{1}+M_{2}} ) D. none of these |
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| 393 | A wooden box is placed on a table. The normal force on the box from the table is ( N_{1} . ) Now another identical box is kept on first box and the normal force on lower block due to upper block is ( N_{2} ) and normal force on lower block by the table is ( N_{3} . ) For this situation, mark out the correct statement(s) A. ( N_{1}=N_{2}=N_{3} ) в. ( N_{1}<N_{2}=N_{3} ) c. ( N_{1}=N_{2}N_{3} ) |
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| 394 | Illustration 7.38 In Fig. 7.130, the co-efficient of friction between the walls of block of mass m and the plank of mass Mis u. The same co-efficient of friction is there between the plank and the horizontal floor. The force F is of 100 μ N and the masses m and M are of 1 kg and 3 kg, respectively. Find the value of u, if the block does not slip along the Fig. 7.130 wall of the plank. |
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| 395 | A particle of mass m moving with velocity u makes an elastic one dimensional collision with a stationary particle of mass m. They are in contact for a short time T. Their force of interaction increases from zero to ( F_{0} ) linearly in time ( frac{T}{2} ) and decreases inearly to zero in further time ( frac{T}{2} ) (shown in figure) The magnitude of ( F_{0} ) is : A . ( m u / 2 T ) в. ( m u / T ) ( mathrm{c} .2 mathrm{mu} / mathrm{T} ) D. None of these |
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| 396 | The block shown moves with constant velocity on a horizontal surface. Two of the forces on it are shown. A frictiona force exerted by the surface is the only other horizontal force on the block. The frictional force is ( A ) c. ( 2 mathrm{N} ), rightward D. slightly more than 2 N, leftward |
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| 397 | Two block ( A ) and ( B ) are arranged as shown in the figure. The mass of block ( A ) is 10 kg. The coefficient of friction between the block ( A ) and the horizontal plane is ( 0.2 . ) The minimum mass of block ( B ) to start motion will be A . ( 0.2 mathrm{kg} ) в. ( 10 mathrm{kg} ) ( c .5 k g ) D. ( 2 k g ) |
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| 398 | Regarding linear momentum of a body a. It is a measure of quantity of motion contained by the body b. Change in momentum is the measure of impulse c. Impulse and acceleration act in opposite direction to the change in momentum d. In the case of uniform circular motion the linear momentum is conserved. ( A cdot ) a ( & b ) are true B. b & c are true c. ( c & ) d are true D. a, b & c are ture |
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| 399 | Find the value of friction forces between the blocks ( A ) and ( B ) and between ( B ) and ground (Take ( left.g=10 m s^{-2}right) ) ( A cdot 90 N, 5 N ) B. 5 N, 90 ( N ) ( c cdot 5 N, 75 N ) D. O N, 80 N |
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| 400 | If ( mu_{s}, mu_{k} ) and ( mu_{r} ) are coefficient of static friction, sliding friction and rolling friction, then A ( cdot mu_{s}<mu_{k}<mu_{r} ) B . ( mu_{k}<mu_{r}<mu_{s} ) c. ( mu_{r}<mu_{k}<mu_{s} ) D. ( mu_{r}=mu_{k}=mu_{s} ) |
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| 401 | A turn of radius ( 20 mathrm{m} ) is banked for the vehicle of mass ( 200 mathrm{kg} ) going at a speed of ( 10 mathrm{m} / mathrm{s} ). Find the direction and magnitude of frictional force acting on a vehicle if it moves with a speed 15 ( mathrm{m} / mathrm{s} . ) Assume that friction is sufficient to prevent slipping. ( left(boldsymbol{g}=mathbf{1 0 m} / boldsymbol{s}^{2}right) ) |
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| 402 | Top view of a block on a table is shown ( left(g=10 m / s^{2}right) ) Find out the acceleration of the block. A. 0.6 3. 0.8 ( c .1 . ) D. 0.5 |
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| 403 | Which of the following is easier to hold with a greasy palm? A . a glass tumbler B. a polished crockery piece c. a metal container D. an earthen pot |
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| 404 | A disc rotates about its axis of symmetry in a horizontal plane at a steady rate of 3.5 revolutions per second. A coin placed at a distance of ( 1.25 mathrm{cm} ) from the axis of rotation remains at rest on the disc. The coefficient of friction between the coin and the disc is : A. 0.5 B. 0.3 ( c . ) о. D. 0.60 |
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| 405 | Starting from rest, a body slides down a 45 degrees inclined plane in twice the time it takes to slide down the same distance in the absence of friction. The coefficient of friction between the body and the inclined plane is: A . 0.33 B. 0.25 c. 0.75 D. 0.80 |
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| 406 | A stationary ball weighing ( 0.25 mathrm{kg} ) acquires a speed of ( 10 mathrm{m} / mathrm{s} ) when hit by a hockey stick. The impulse imparted to the ball is : A . 2.5 Ns B. 2.0Ns c. ( 1.5 mathrm{Ns} ) D. 0.5Ns |
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| 407 | Which of the following quantities has equivalent units as Impulse? A. Displacement B. Velocity c. Acceleration D. Linear momentum E. Kinetic energy |
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| 408 | 2. A block of mass 0.18 kg is attached to a spring of force constant 2 Nm . The coefficient of friction between the block and the floor is 0.1. Initially the block is at rest and the spring is unstretched. An impulse is given to the block as shown in Fig. 8.317. The block slides a distance of 0.06 m and comes to rest for the first time. The initial velocity of the block in msis V=N/10. Then N is Fooooo Fig. 8.317 (IIT JEE, 2011) |
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| 409 | C. 12N d. 15 N 11. Two masses each equal to m are lying on x-axis at (-a,0) and (+a, 0), respectively, as shown in Fig. (a,0) (a,0) 7.363. They are connected by a light string. A force F is applied Fig. 7.363 at the origin along vertical direction. As a result, the masses move towards each other without loosing contact with ground. What is the acceleration of each mass? Assume the instantaneous position of the masses as (-x,0) and (x, 0), respectively, (IIT JEE, 2004) 2F Va² – F X m x D. m Va²-x² F d. in Ja²-x² A l mamiaanan inclined nlanafanale 0 TL |
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| 410 | Find the acceleration of the block of mass ( mathrm{M} ) in the arrangement shown in the figure. The coefficient of friction between the two blocks is ( mu_{1} ) and that between the bigger block and the ground is ( mu_{2} ) |
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| 411 | A body of mass ( 5 k g ) is moving with a constant velocity of ( 18 mathrm{m} / mathrm{s} ) on a friction less horizontal surface. The force required to keep this body moving with the same velocity is ( A cdot 5 N ) B. ( 45 N ) ( c .90 N ) D. ( 0 N ) |
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| 412 | State five differences between mass and weight. |
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| 413 | State whether true or false. Weight of a body remains constant anywhere in the universe. A. True B. False |
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| 414 | In which of the following cases more friction is desirable? A. Movement of piston in a cylinder B. Braking of a vehicle c. skating on a track D. All of the above |
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| 415 | Example 7.3 Blocks A, B, and C are placed as shown in Fig. 7.207 and connected by the ropes of negligible mass. Both A and B weigh 25.0 Neach, and the coefficient of kinetic friction between each block and the surface is 0.35. Block C descends with constant velocity. 370 Fig. 7.207 a. Draw two separate free-body diagrams showing the forces acting on A and B. b. Find the tension in the rope connecting blocks A and B. c. What is the weight of block C ? d. If the rope connecting A and B were cut, what would be the acceleration of C? |
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| 416 | If you can change location of the point ( A ) on the wall and hence the orientation of the string OA without altering the orientation of the string ( 0 mathrm{B} ) as shown in figure-II. What angle should the string OA make with the wall so that a minimum tension is developed in it? |
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| 417 | A block of mass m slides with velocity of ( 10 m / s ) on a rough horizontal surface It comes to rest after converting a distance of 50 meters. If ( g ) is ( 10 m / s e c^{2} ) then the coefficient of dynamic friction between the block and the surface is A . ( 0 . ) B. 1 c. 10 D. 5 |
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| 418 | When a moving body is suddenly stopped, then: A. Frictional force increases. B. Friction force remains same as it was while the car was moving. C. Friction force reduces but has a non zero value. D. Frictional force reduces to zero as it is a self adjusting force. |
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| 419 | A particle with linear momentum of magnitude ( P ) is subjected to a force ( F= ) ( mathrm{Kt}(mathrm{k}>0) ) which is directed along the directed of initial momentum. The time which its liner momentum changes to ( 3 P ) is : A ( cdot sqrt{frac{2 P}{K}} ) в. ( 2 sqrt{frac{P}{K}} ) c. ( sqrt{frac{2 K}{P}} ) D. ( 2 sqrt{frac{K}{P}} ) |
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| 420 | A van is moving with a speed of 72 ( k m p h ) on a level road, where the coefficient of friction between tyres and road is ( 0.5 . ) The minimum radius of curvature, the road must have, for safe driving of van, is ( left(g=10 m / s^{2}right) ) A. ( 80 m ) в. ( 40 mathrm{m} ) ( c .20 m ) D. ( 4 m ) |
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| 421 | acceleration of mz is ms-2 ms? d. None of these |
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| 422 | How does the proper inflation of tyre save fuel? A. Normal reaction decreases. B. Normal reaction increases c. Sliding contact with the road decreases. D. Sliding contact with the road increases |
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| 423 | 89. A bead of mass 1/2 kg starts from rest from A to move in a vertical plane along a smooth fixed quarter ring of radius 5 m, under the action of a constant horizontal force F = N as shown in Fig. 8.263. The speed of bead as it reaches point B is R = 5 m B- —– Fig. 8.263 a. 14.14 ms-‘b. 7.07 ms-:c. 5 ms? d. 25 ms -1 |
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| 424 | The magnitude of the force (in Newton) acting on a body varies with time ( t ) (in microseconds) as shown in the figure. ( A B, B C ) and ( C D ) are straight line segments. The magnitude of the total impulse of the force in the body from ( boldsymbol{t}=mathbf{4} boldsymbol{mu} boldsymbol{s} ) to ( boldsymbol{t}=mathbf{1 6} boldsymbol{mu} boldsymbol{s} ) is Ns. ( mathbf{A} cdot 1.005 ) B. 0.005 c. 2.005 D. 4.005 |
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| 425 | If action is always equal to reaction;explain |
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| 426 | A force acts on a body of mass ( 3 mathrm{kg} ) such that its velocity changes from ( 4 mathrm{m} ) ( s^{-1} ) to ( 10 mathrm{m} s^{-1} . ) Calculate the change in the momentum of the body. A ( cdot 2 mathrm{kg} mathrm{m} s^{-1} ) B. 14 kg m s ( ^{-1} ) c. ( 18 mathrm{kg} mathrm{m} s^{-1} ) D. ( 42 mathrm{kg} mathrm{m} mathrm{s}^{-1} ) |
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| 427 | In Fig. 6.357, a man of true mass M is standing on a weighing machine placed in a cabin. The cabin is joined by a string with a body of mass m. Assuming no friction, and negligible mass of cabin and weighing machine, the measured mass of man is (normal force between the man and the machine is proportional to the mass) Fig. 6.357 Mm a. The measured mass of man is – (M+m) mg b. The acceleration of man is – (M+m) Mg c. The acceleration of man is – (M + m) d. The measured mass of man is M. . PO. |
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| 428 | Assertion When a ball of mass ( mathrm{m} ) hits normally a wall with a velocity ( v ) and rebounds with same velocity ( v, ) impulse imparted to the wall is ( 2 m v ) Reason Impulse = change in linear momentum A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
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| 429 | 95. A stone of mass 1 kg tied to a light inextensible string of length L = 10/3 m is whirling in a circular path of radius L in a vertical plane. If the ratio of the maximum tension in the string to the minimum tension is 4 and if g is taken to be 10 ms, the speed of the stone at the highest point of the circle is a. 10 ms-1 b. 53 ms- c. 10/3 ms -1 d. 20 ms-1 |
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| 430 | The minimum force required to move a body of mass m vertically upward is ( mathbf{A} cdot mathbf{m g} ) B. mg/2 C. more that ( 2 mathrm{mg} ) D. more than mg |
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| 431 | State and explain the laws of limits friction. | 11 |
| 432 | Momentum is a measure of quantity of A. motion B. friction c. gravitation D. electric force |
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| 433 | A force of ( 20 mathrm{N} ) acting on a body of mass ( 10 mathrm{kg} ) is found to double its velocity in 8 s. Find its initial velocity? ( A cdot 6 m s^{-1} ) B . ( 16 mathrm{m} mathrm{s}^{-1} ) ( c cdot 8 m s^{-1} ) D. ( 10 mathrm{m} mathrm{s}^{-1} ) |
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| 434 | Angle between force and momentum vectors in uniform circular motion is A . ( 0^{circ} ) B. ( 30^{circ} ) ( c cdot 45^{circ} ) D. ( 90^{circ} ) |
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| 435 | Materials used to reduce friction are called ( _{text {一一一一一一 }} ) (lubricants, beverages) |
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| 436 | Illustration 8.50 A particle of mass m is kept on a fixed, smooth sphere of radius R at a position where the radius through the particle makes an angle of 30° with the vertical. The particle is released from this position. a. What is the force exerted by the sphere on the particle just after the release ? b. Find the distance travelled by the particle before it leaves contact with the sphere. |
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| 437 | If the racing cars move on a circular road of radius ( 100 mathrm{m}, ) with a speed of ( 30 mathrm{m} / mathrm{s}, ) with an angle of banking equal to 15 degrees, what will be the coefficient of friction for safe driving A . ( 0 . ) B. 0.3 ( c cdot 0.5 ) D. 0.8 |
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| 438 | спе Banks Type 1. A block of mass 1 kg lies on a horizontal surface in a truck. The coefficient of static friction between the block and the surface is 0.6. If the acceleration of the truck is 5 ms, the frictional force acting on the block is ….. N. (IIT JEE, 1984) |
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| 439 | Before burning the thread, what are the tensions in spring and thread BC, respectively? a. m18,28 b. m 8, m 8-m28 c. m28, m 8 d. m 8,m,8 + m28 |
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| 440 | Consider the situation shown in the figure . The tension in the string connecting the 1.0 kg blocks. |
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| 441 | 11. A body of mass M is resting on a rough horizontal plane surface, the coefficient of friction being equal to u. At 1 = 0, a horizontal force F= Fot starts acting on it, where Fo is a constant. Find the time T at which the motion starts? a. uMg/F. b. Mg/uFo c. uF/Mg d. None of these |
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| 442 | State whether given statement is True or False. Force never exists in pairs. A. True B. False |
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| 443 | Assertion A rocket work on the principle of linear momentum. Reason Whenever there is the change in momentum of one body, the same change occur in the momentum of the second body of the same system but in the opposite direction. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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| 444 | Two blocks ( A ) and ( B ) each of 20 kg lying on a frictionless table are connected by a light string. The system is pulled horizontally with an acceleration of ( 2 m s^{-2} ) by a force ( F ) on ( B . ) The tension in the string will be: A. ( 10 N ) в. ( 40 N ) c. ( 100 N ) D. ( 120 N ) |
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| 445 | A ball is moving over a horizontal smooth surface with a constant velocity. Sum of external forces is: A. zero B. positive c. negative D. unity |
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| 446 | methods is same. Illustration 6.24 A bob of mass m = 50 g is suspended from the ceiling of a trolley by a light inextensible string. If the trolley accelerates horizontally. the string makes an angle 8=37° with the vertical. Find the acceleration of the trolley. Fig. 6.70 |
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| 447 | 9. A particle is released from height h on a smooth track terminating in a circular path of radius R. A and Care points at top and at horizontal level of centre, respectively, of the circular path. Column I represents the different values of height of inclined plane and Column II gives the conditions during the motion of the particle. Fig. 8.295 Column I Column II i. If h = 3.2R ii. If h=2.7R iii. If h=2.5R a. the particle is able to complete vertical circular motion b. the force exerted by the particle on the track at point A is zero c. the force exerted by the particle on the track at point A is more than its weight d. the force exerted by the particle on the track at point C is more than its weight iv. If h = 4R |
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| 448 | If the acceleration of an object is zero: A. it must be at rest B. it may or may not be at rest c. it must be moving D. it must be falling freely under gravity |
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| 449 | A toy car released with the same initial speed will travel farthest on: A. muddy surface. B. polished marble surface c. cemented surface D. brick surface |
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| 450 | Assuming a person could survive in all of the following locations, where would this person have the most mass? A. on the surface of the earth B. on the surface of the moon c. on the surface of Jupiter D. on the surface of the sun E. same mass at all locations |
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| 451 | Which of the following statements are true? This question has multiple correct options A. Impulse is the product of force and time for which the force acts. B. Sl unit of impulse is N s. C. When two bodies have the same velocity; the lighter body has more momentum. D. Conservation of linear momentum has no connection with “Newton’s third law of motion”” |
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| 452 | Assertion Frictional force is independ of the velocity of the body Reason Friction is due to surface irreqularities. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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| 453 | Illustration 7.26 In Fig. 7.92, Block m, is loaded on block m. If there is no relative sliding between the blocks and the inclined plane is smooth, find the friction force between the blocks. m2 Fig. 7.92 |
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| 454 | A block of mass ( m ) slides down an inclined right angled trough. If the coefficient of kinetic friction between the block and the trough is ( mu_{k} ) acceleration of the block down the plane is: ( mathbf{A} cdot gleft(sin theta-2 mu_{k} cos thetaright) ) B ( cdot gleft(sin theta+2 mu_{k} cos thetaright) ) ( mathbf{c} cdot gleft(sin theta-sqrt{2} mu_{k} cos thetaright) ) ( mathbf{D} cdot gleft(sin theta-mu_{k} cos thetaright) ) |
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| 455 | The three flat blocks as shown in the figure are positioned on the ( 37^{circ} ) incline and a force ( P ) parallel to the inclined plane is applied to the middle block. The upper block is prevented from moving by a wire which attaches it to the fixed support. The masses of three blocks in kg and coefficient of static function for each of the three pairs of contact surfaces are shown in the figure. Determine the maximum value which force ( P ) may have before slipping take place anywhere. ( left(boldsymbol{g}=mathbf{1 0 m} / boldsymbol{s}^{2}right) ) |
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| 456 | A cyclist is riding with a speed of 27 ( mathrm{km} / mathrm{h} ). As he approaches a circular turn on the road of radius ( 80 mathrm{m}, ) he applies brakes and reduces his speed at the constant rate of ( 0.50 mathrm{m} / mathrm{s} ) every second. What is the magnitude and direction of the net acceleration of the cyclist on the circular turn? |
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| 457 | An object free falls ( 15 m ) from the top of a ladder. Select the graph that best describes the following quantities during the fall. The momentum of the object ( A cdot A ) B. B ( c cdot c ) D. ( E ) |
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| 458 | Figure shows two blocks in contact sliding down an inclined surface of inclination ( 30^{circ} . ) The friction coefficient between the block of mass ( 2.0 mathrm{kg} ) and the incline is ( mu_{1}=0.20 ) and that between the block of mass ( 4.0 mathrm{kg} ) and the incline ( mu_{2}=0.30 . ) is Find the acceleration of ( 2.0 mathrm{kg} ) block. ( (mathrm{g}= ) ( left.10 m / s^{-2}right) ) A ( cdot 2.7 m / s^{2} ) B ( .2 .2 m / s^{2} ) ( mathrm{c} cdot 3.7 mathrm{m} / mathrm{s}^{2} ) D. ( 3.2 m / s^{2} ) |
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| 459 | Q Type your question. projected towards the pulley’P’ with an initial velocity ( u_{0} ) then select incorrect option A the string would become tight at ( t=frac{2 u_{0}}{g} ) 3. the distance travelled by ‘A’ before the string is taut is ( frac{u_{0}^{2}}{g} ) c. the distance travelled by ‘B’ before string is taut is ( frac{2 u_{0}^{2}}{g} ) D. the common speed of the blocks just after the string i aut is ( left[frac{n+2}{n+1}right] u_{0} ) |
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| 460 | An object of mass ( 10 mathrm{kg} ) is to be kept at rest on an inclined plane making an angle of ( 37^{0} ) to the horizontal by applying a force ( F ) along the plane upwards as shown in Fig. The coefficient of static friction between the object and the plane is 0.2 . Find the magnitude of force ( F ) [Take ( left.g=10 m s^{-2}right] ) ( sin 37^{circ}=0.6 ) ( cos 37^{circ}=0.8 ) |
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| 461 | A body of mass ( mathrm{M} ) is kept on a rough horizontal surface (friction coefficient = ( mu ) ). A person is trying to pull the body by applying a horizontal force but the body is not moving. The force by the surface on A is F where A. ( F=M g ) в. ( F=mu M g ) c. ( M g leq F leq M g sqrt{1+mu^{2}} ) D. ( M g geq F geq M g sqrt{1-mu^{2}} ) |
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| 462 | If the earth shrinks half in radius with its mass remaining the same, the weight of an object on earth will : A. decrease by ( 50 % ) B. increase by ( 50 % ) c. decrease by ( 25 % ) D. increase by ( 300 % ) |
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| 463 | 5. A block A, of weight W, slides down an inclined plane S of slope 37° at a constant velocity, while the plank B, also of weight W, rests on top of A. The plank B is attached by a B cord to the top of the plane. The coefficient of kinetic friction u is the same between the surfaces S =3 A and B and between S and A. Fig. 7.356 Determine the value of 1/u. |
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| 464 | Give reasons for the following: It is dangerous to get down from a moving bus even if the bus is moving slowly. |
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| 465 | Air resistance is also a form of friction. A. True B. False |
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| 466 | Illustration 7.27 Two blocks of masses M and mare arranged as shown in Fig. 7.94. There is no friction between ground and block M. The coefficients of static and kinetic friction between M and m are us and Hje, respectively. a. Calculate the maximum Fig. 7.94 possible value of F so that both the bodies move together. b. Find the accelerations of the blocks if F is greater than that found in part (a). |
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| 467 | Four identical planks each of length a are arranged one above the other over a table as shown. Each projects a distance beyond the edge of the one that is below it. The maximum value for L so that no block topple is A ( cdot frac{a}{2} ) B. ( frac{3 a}{4} ) c. ( frac{25 a}{24} ) D. ( frac{11 a}{12} ) |
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| 468 | 20. The tension in the string attached to m is a. 40 N b. 10 N c. 20 d. 5 N |
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| 469 | The coefficient of friction between a car’s wheels and a roadway is ( 0.5 . ) The least distance in which the car can accelerate from rest to a speed of 72 ( boldsymbol{k m p h} ) is ( left(boldsymbol{g}=mathbf{1 0} boldsymbol{m s}^{-2}right) ) A . ( 10 m ) в. ( 20 m ) ( c .30 m ) D. ( 40 m ) |
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| 470 | Explain why objects moving in fluids must have special shapes. | 11 |
| 471 | 1. Statement I: The driver of a moving car sees a wall in front of him. To avoid collision, he should apply brakes rather than taking a turn away from the wall. Statement II: Frictional force is needed to stop the car or taking a turn on a horizontal road, |
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| 472 | Two boxes ( A ) and ( B ) weighing 5 kg and 10 kg respectively, have to be pushed along the same slope. In which case will the frictional force be more? ( A cdot B O x A ) B. Box B c. same for both D. Unsure |
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| 473 | Mass differs from weight in which ways: A. weight is a force where as mass is not a force. B. the mass of an object is always more than its weight. C. mass can be expressed only in the metric system. D. there is no difference |
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| 474 | Which of the below statements prove that friction is disadvantageous? A. Tyres of cars wear out B. Soles of shoes wear out c. Machine parts wear out D. All of the above |
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| 475 | A uniform metre rule which has a mass of ( 75 g ) is suspended by a thread at the ( 75 mathrm{cm} ) mark and is balanced by a mass of weight Whanging from the ( 90 mathrm{cm} ) mark. Calculate the value of W. A . 75 g B. 125 g ( c cdot 150 g ) D. 250 g |
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| 476 | mall ring of mass m passes through a smooth wire bent the form of a horizontal circle. The ring is connected to a spring whose other end is fixed at A on the wire as in Fig. 8.296. The natural length of the spring is R and the spring constant is mg/R, where m is the mass of the ring and R is the radius of the circle. Initially, the ring is released from rest from position B and it moves towards C as shown in Fig. 8.232. (N is the Normal reaction between wire and ring, Vis the speed of the ring). Match the following. wire 60° 000000B Fig. 8.296 Column 1 Column I i. N= mg a. at position B ii. N=0 b. at position C iii. N= V2 mg c. somewhere between position B and position C. iv. v= vg d. never |
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| 477 | 1. Two skaters have weight in the ratio 4 : 5 and are 9 m apart, on a smooth frictionless surface. They pull on a rope stretched between them. The ratio of the distance covered by them when they meet each other will be a. 5:4 b. 4:5 c. 25: 16 d. 16:25 |
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| 478 | A plane travelling at ( 300 m / s ) banks its wings to enter into a horizontal circular turn. The circular path has a radius of ( 2.7 k m ) Which of these values best represents the angle of the wings relative to the horizontal if the plane experiences no change in its altitude during the turn? A ( cdot 8^{circ} ) B. 16 ( c cdot 20^{circ} ) D. ( 25^{circ} ) E ( .32^{circ} ) |
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| 479 | Inertia of a body has direct dependence on: A. Velocity B. Volume c. Mass D. Density |
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| 480 | Which of the following has more inertia ( ? ) A bicycle or a train |
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| 481 | Two spheres are placed into free fall from rest. Sphere B has a mass three times larger than sphere A.Which statement(s) correctly explains the situation? I. Sphere B falls faster. Il. Sphere B has more momentum when the two reach the ground. III. Both spheres reach the ground with the same kinetic energy A. I only B. II only c. I and III only D. II and II only E . ।, II, and III |
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| 482 | Two balls of same mass are dropped from the same height ( h, ) on to the floor The first ball bounces to a height ( boldsymbol{h} / mathbf{4} ) after the collision and the second ball into a height ( h / 16 . ) The impulse applied by the first and second ball on the floor are ( I_{1} ) and ( I_{2} ) respectively. Then A ( cdot 5 I_{1}=6 I_{2} ) B ( .6 I_{1}=5 I_{2} ) ( mathbf{c} cdot I_{1}=2 I_{2} ) D. ( 2 I_{1}=I_{2} ) |
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| 483 | External forces are always balanced State whether true or false. A. True B. False |
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| 484 | A player kicks a football of mass ( 0.5 mathrm{kg} ) and the football begins to move with a velocity of ( 10 mathrm{m} / mathrm{s} ). If the contact between the leg and the football lasts for ( frac{1}{50} ) sec, then the force acted on the football should be A ( .2500 N ) в. ( 1250 N ) c. ( 250 N ) D. ( 625 N ) |
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| 485 | In the arrangement, shown in figure, pulleys are massless and frictionless and threads are inextensible block of ( operatorname{mass} boldsymbol{m}_{2} ) will remain at rest if. ( ^{mathrm{A}} cdot frac{1}{m_{1}}=frac{1}{m_{2}}+frac{1}{m_{3}} ) в. ( frac{4}{m_{1}}=frac{1}{m_{2}}+frac{1}{m_{3}} ) ( mathbf{c} cdot m_{1}=m_{2}+m_{3} ) D. ( frac{1}{m_{3}}=frac{2}{m_{2}}+frac{3}{m_{1}} ) |
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| 486 | Alida runs her toy car on dry marble floor, wet marble floor, newspaper and towel spread on the floor. The force of friction acting on the car on different surfaces in increasing order will be A. wet marble floor, dry marble floor, newspaper, towel. B. newspaper,towel, dry marble floor, wet marble floor. c. towel,newspaper, dry marble floor, wet marble floor. D. wet marble floor, dry marble floor, towel, newspaper. |
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| 487 | Suppose your writing desk is titled a little. A book kept on it starts sliding down. Show the direction of frictional force acting on it. |
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| 488 | Which law is referred to as the law of inertia? A. First law of motion B. Second law of motion c. Third law of motion D. None of these |
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| 489 | Calculate the maximum speed with which a car can be driven safely along a curved road of radius ( 30 m ) and banked at ( 30^{circ} ) with the horizontal. Given, ( g= ) ( 9.8 m s^{-2} ) A ( cdot 13.03 mathrm{ms}^{-1} ) B . ( 12.08 mathrm{ms}^{-1} ) ( mathbf{c} cdot 15.08 m s^{-1} ) D. ( 14.02 mathrm{ms}^{-1} ) |
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| 490 | A bullet of mass 60 g moving with the velocity of ( 500 mathrm{m} / mathrm{s} ) is brought to rest in ( 0.01 mathrm{s} . ) Its impulse will be? | 11 |
| 491 | toppr Q Type your question the block ( A ) is placed is taken to be smooth. A horizontal force ( F, ) increasing linearly with time, begins to act on B. The accelerations ( a_{A} ) and ( a_{B} ) of blocks A and B respectively are plotted against t. The correctly plotted graph is: 4 B. ( c ) D. none of the above |
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| 492 | A person of ( 40 mathrm{kg} ) is managing to be at rest between 2 vertical walls by pressing one wall ( A ) by his hands and feet and ( mathrm{B} ) with his back as shown in fie The coeff. of friction between his body and the wall is 0.8 . The normal force exerted by the person is ( left(g-10 m / s^{2}right) ) ( mathbf{A} cdot 250 N ) B. ( 290 N ) ( c cdot 100 N ) D. ( 106 N ) |
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| 493 | Impulse 0.45 is applied to a 200 g model rocket at rest what will be its final speed? (neglect gravity) ( A cdot 2.25 mathrm{m} / mathrm{s} ) B. 22.5 ( mathrm{m} / mathrm{s} ) c. ( 2250 mathrm{m} / mathrm{s} ) D. ( 4500 mathrm{m} / mathrm{s} ) |
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| 494 | 24. Block B has mass m and is released from rest when it is on top of wedge A, which has a mass 3m. Determine the tension in cord CD needed to hold the wedge from moving while B is sliding down A. Neglect friction. 3D Fig. 6.312 a. 2mg cos 0 b. mg cos e c. me sine d. mg sin 20 |
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| 495 | A block of mass ( 5 mathrm{kg} ) rests on a rough horizontal surface. It is found that a force of ( 10 mathrm{N} ) is required to make the block just move. However, once the motion begins, a force of only ( 8 mathrm{N} ) is enough to maintain the motion. Find the coefficients of kinetic and static friction between the block and the horizontal surface. ( sqrt{38}-7 ) |
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| 496 | Maximum safe speed does not depend upon A. radius of curvature B. angle of inclination with the horizontal c. mass of the vehicle D. acceleration due to gravity |
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| 497 | The magnitude of the impulse developed by a mass of ( 0.2 mathrm{kg} ) which changes its velocity from ( 5 hat{i}+3 hat{j}+7 hat{k} ) ( mathrm{m} / mathrm{s} ) to ( 2 hat{boldsymbol{i}}+boldsymbol{3} hat{boldsymbol{j}}+hat{boldsymbol{k}} ) A . ( 2.7 mathrm{N}-mathrm{s} ) B. 1.3N-s c. ( 0.9 N- ) s D. 3.6N-s |
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| 498 | A ring of mass kept on a horizontal rough A force ( F ) is applied tangentially at its rim as shown. The coefficient of frictionless between the ring and the surface is ( mu ) Then A. Friction will act in the forward direction B. Friction will act in the backward direction c. Friction force will not act D. Frictional force will be ( mu g ) |
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| 499 | A block kept on a rough surface starts sliding when the inclination of the surface is ‘ ( theta ) ‘ with respect to the horizontal. The coefficient of static friction between the block and the surface is: ( A cdot sin theta ) B. ( tan theta ) ( c cdot cos theta ) D. ( sec theta ) |
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| 500 | If circular race track is banked at angle ( theta(theta>text { angle of repose }), ) radius of track is ( r ) and ( mu ) is coefficient of friction between car and road. Calculate minimum speed on car on inclined plane to avoid slipping? ( A ) [ v=left[r gleft(frac{tan theta-mu}{1+mu tan theta}right)right] ] B. [ v=left[r gleft(frac{tan theta+mu}{1-mu tan theta}right)right] ] ( c ) [ v=left[r gleft(frac{tan theta-mu}{1+mu tan theta}right)right]^{1 / 2} ] D. [ v=left[r gleft(frac{tan theta+mu}{1+mu tan theta}right)right]^{1 / 2} ] |
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| 501 | Galilee’s law of inertia is another name for newton’s (…) law of motion. A. First B. second c. Third D. Anyone of the above |
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| 502 | An astronaut in a space station orbits above the Earth. In the space station, the acceleration |
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| 503 | If it is safe to jump from a height of ( 2 m ) on to the earth, what would be the safe height on a planet where the value of ‘g’ is ( 1.96 m s^{-2} ? ) A . ( 2 m ) в. ( 4 m ) ( c .6 m ) D. ( 10 m ) |
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| 504 | 10. Each of the three blocks in Fig. 7.248 has a mass of 10 kg. The coefficients of static and kinetic frictions at each surface of contact between the blocks are pr=0.3 and Mx=0.2, 25 N + respectively. The ground is smooth. Determine the accel- 100 N eration of each block when the horizontal forces as shown are Fig. 7.248 applied. 11 Roll 15 N |
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| 505 | A meteor burns up on entering earth’s atmosphere due to: A. atmospheric pressure B. heat of the earth c. solar radiation D. excessive friction |
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| 506 | the inclined alculate the hen the block is Example 6.5 A block of mass m is placed on the surface of a wedge as shown in Fig. 6.249. Calcula acceleration of the wedge and the block when the released. Assume all surfaces are frictionless. Fig. 6.249 V hod 1. Analysis from around frame. La |
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| 507 | begin{tabular}{l|l|l} List & multicolumn{1}{l} { List } \ I & II \ A. & A dusting of a carpet & Inertia of direction \ B. & Provided with a mudguard & Inertia of motion \ C. & Fan continues to rotate after switching off & Measure of inertia \ hline D. & Mass & Inertia of rest end{tabular} ( mathbf{A} ) ( A-(4) ; B-(1) ; C-(3) ; D-(2) ) ( mathbf{B} ) ( A-(4) ; B-(1) ; C-(2) ; D-(3) ) C ( cdot A-(4) ; B-(2) ; C-(1) ; D-(3) ) D. ( A-(1) ; B-(4) ; C-(2) ; D-(3) ) |
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| 508 | A ( 20 mathrm{kg} ) block is in motion on a rough horizontal surface. A horizontal force of ( 60 mathrm{N} ) is requited to keep the body moving with constant speed. Then the coefficient of kinetic friction is ( 3 times ) ( 10^{-x} . ) Find the value of ( x .left(g=10 m s^{-2}right) ) |
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| 509 | Newton’s first law of motion is also called Galileo’s law of: A. Conservation of momentum B. Inertia c. Friction D. conservation of mass |
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| 510 | A ( 60 mathrm{kg} ) man pushes a ( 40 mathrm{kg} ) man by a force of ( 60 N . ) The ( 40 mathrm{kg} ) man has pushed the other man with a force of: A ( .40 N ) B. 0 ( c .60 N ) D. 20 N |
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| 511 | Which among the following is not a property of mass? A. It is the amount of matter contained in a body. B. It is measured by a physical balance. C. It varies as per the location. D. Its S.I unit is kilogram. |
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| 512 | According of Newton’s Third Law of Motion, action and reaction are equal and opposite. The resultant force is not zero because A. They act at different times B. They act on different bodies c. Their lines of action are different D. They act on the same body |
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| 513 | “I is smooth wall, as shown in the diagram, making a variable angle ( theta ) with the horizontal floor. There is no friction with the vertical wall. At which angle ( theta ) will the normal force exerted by the floor upwards be at its maximum? Do not consider any motion by the plank (consider the forces exerted when the plank is perfectly still for a given angle ( theta) ) A. When ( theta=0.00^{circ} ) (the plank is horizontal) B. When ( theta=45.0^{circ} ) C. When ( theta=90.0^{circ} ) (the plank is vertical) D. The angle ( theta ) makes no difference E. More information is needed |
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| 514 | A body of ( 6 k g ) rests in limiting equilibrium on an inclined plane whose slope is ( 30^{circ} . ) If the plane is raised to slope of ( 60^{circ}, ) then force ( (operatorname{in} k g-w t) ) along the plane required to support it is A . 3 B. ( 2 sqrt{3} ) ( c cdot sqrt{3} ) D. ( 3 sqrt{3} ) |
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| 515 | Column I contains physical quantity/process while column I contains formula/principle. Match column I and II such that the formula/principle is correct corresponding to the quantity in column I. |
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| 516 | A curved road of diameter ( 1.8 mathrm{km} ) is banked so that no friction is required at a speed of ( 30 m / s . ) What is the banking angle? A ( cdot 6 ) B. 16 ( c cdot 26 ) D. ( 0.6^{circ} ) |
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| 517 | 17. The mass of the wedge shown in Fig. 7.255 is M 4 ke and that of the block is m= 1 kg. The horizontal surfac beneath the wedge is smooth while the coefficient of friction between vertical surface of the wedge and block is equal to p = 0.1. Taking 8 = 9.8 ms? and assuming pulleys to be massless and frictionless, calculate maximum possible value of force F, upto which the block will remain stationary relative to the wedge. im Smooth Fig. 7.255 |
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| 518 | The velocity of a body of mass ( 20 mathrm{kg} ) increases to ( 400 mathrm{kgm} / mathrm{s} ) in ( 5 mathrm{s} ). If initia velocity was ( 10 mathrm{m} / mathrm{s} ), what is the momentum before the force acts? A. ( 200 k g . m / s^{2} ) в. 300 kg.m / ( s ) c. 200 kg.m ( / s ) D. 100 kg.m ( / s ) |
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| 519 | Which of the following physical quantities has the same units as that of impulse? A. Momentum B. Force c. Torque D. couple |
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| 520 | The flying of birds is a proof of Newton’s: A. First law B. Second law c. Third law of motion D. Both second and third law |
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| 521 | Statement 1: There can be displacement of an object even in the absence of any force acting on it. Statement 2: An object in uniform motion in a straight line shows displacement even when the net force acting on it is zero. A. Both statement 1 and statement 2 are true and statement 2 is correct explanation of statement B. Both statement 1 and statement 2 are true, but statement 2 is not correct explanation of statement c. statement 1 is true but statement 2 is false D. Statement 1 is false but statement 2 is true |
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| 522 | Consider the situation shown in fig. The wall is smooth but the surface of ( A ) and B in contact are rough The friction on B due to A in equilibrium- A. is upward c. is zero D. the system cannot remain in equilibrium |
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| 523 | Rolling friction varies with velocity. This statement is : A . True B. False |
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| 524 | A block of mass ( m ) and surface area ( A ) just begins to slide down an inclined plane when the angle of inclination is ( pi / 5 . ) Keeping the mass of the block same, if the surface area is doubled, the inclination of the plane at which the block starts sliding will be: A ( . pi / 5 ) в. ( pi / 10 ) c. ( 2 pi / 5 ) D. ( pi / 5 sqrt{2} ) |
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| 525 | In the above question, find out the magnitude of net force exerted by the pulley on the road ( boldsymbol{R}_{mathbf{1}} ) A ( .2 F ) в. ( F ) c. ( 2 sqrt{2} F ) D. ( frac{F}{sqrt{2}} ) |
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| 526 | A motor cyclist at a speed of ( 5 mathrm{m} / mathrm{s} ) is describing a circle of radius ( 25 mathrm{m} ). Find his inclination with vertical. What is the value of coefficient of friction between type and ground? |
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| 527 | Assertion A rocket moves forward by pushing the surrounding air backwards. Reason It derives the necessary thrust to move forward according to Newton’s third law of motion. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
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| 528 | After falling from rest through a height ( h, ) a body of mass ( m ) begins to raise a body of mass ( M(M>m) ) connected to it through a pulley. Find the fraction of kinetic energy lost when the body of mass ( M ) is jerked into motion. A ( cdot frac{M}{M+m} ) в. ( frac{M}{M-m} ) c. ( frac{2 M}{M+m} ) D. ( frac{M}{2(M+m)} ) |
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| 529 | 9. Statement I: Two particles are moving towards each other due to mutual gravitational attraction. The momentum of each particle will increase. Statement II: The rate of change of momentum depends upon Fext: |
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| 530 | 9. What is the speed of the ball at the instant the force a on it is maximum? a. 40 ms- b. 30 ms- c. 20 ms’ d. 10 ms- |
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| 531 | Why are wheels of cars, buses etc. are made circular? A. to minimize friction B. too add more electrostatic force c. no particular reason D. circle looks better |
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| 532 | A man weighing ( 1500 N ) exerts a pressure of ( 105 N / m^{2} ) on the ground. Calculate his area of contact with the ground. |
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| 533 | Figure shows the position-time graph of a particle of mass ( 4 k g . ) What is the ( (a) ) force on the particle for ( t ) ( 4 s, 0<t<4 s ) (b) impulse at ( t=0 ) and ( t ) ( =4 ) s? (Consider one-dimensional motion only). |
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| 534 | Newtons law are not valid in A. Both inertial as well as non- inertial frame of reference. B. A frame moving with constant velocity w.r.t. an inertial frame. C. All reference frames which are at rest w.r.t. an inertial frame D. The reference frame attached to the earth. |
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| 535 | A block of mass ( 300 k g ) is set into motion on a frictionless horizontal surface with the help of frictionless pulley and a rope system as shown in the figure. What horizontal force ( boldsymbol{F} ) should be applied to produce in the block an acceleration of ( 1 mathrm{m} / mathrm{s}^{2} ) ? A. ( 150 N ) в. ( 100 N ) ( c .300 N ) D. ( 50 N ) |
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| 536 | A block of mass 2 kg rests on a rough inclined plane making an angle of ( 30^{circ} ) with the horizontal. The coefficient of static friction between the block and the plane is ( 0.7 . ) The frictional force on the block is ( mathbf{A} cdot 9.8 N ) в. ( 0.7 times 9.8 times sqrt{3} N ) c. ( 9.8 times sqrt{3} N ) D. ( 0.7 times 9.8 N ) |
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| 537 | Assertion Statement 1: When static friction acts, there is no loss of mechanical energy. Reason Statement 2: When kinetic friction acts between two bodies, there is loss of mechanical energy. A. Both Statements1 and 2 are true and Statement 2 is the correct explanation of Statement 1 B. Both Statements 1 and 2 are true, but Statement 2 is not the correct explanation of Statement 1. c. statement 1 is true but Statement 2 is false D. Statement 1 is false but Statement 2 is true |
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| 538 | A block slides down an inclined plane of angle ( 45^{0} ) with constant velocity. If it is then projected up the same plane with velocity ( 10 m s^{-1}, ) then ( left[g=10 m s^{-2}right] ) a. the retardation while going up is ( 10 sqrt{2} m s^{-2} ) b. it comes to rest after moving up for ( frac{1}{sqrt{2}} mathbf{S} ) c. it comes to rest after moving up for ( sqrt{2} ) s. d. coefficient of friction is 0.5 A. a, b & dare correct B. a, c & dare correct c. a & b are correct D. c & dare correct |
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| 539 | The figure represents two bodies of masses ( 10 mathrm{kg} ) and ( 20 mathrm{kg} ) and moving with an initial velocity of ( 10 m s^{-1} ) and ( 5 m s^{-1}, ) respectively. They are colliding with each other, After collision, they are moving with velocities ( 12 m s^{-1}, 4 m s^{-1} ) respectively. The time of collision is 2 s. Then calculate ( F_{1} ) and ( F_{2} ) |
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| 540 | Two blocks of masses ( m_{1} ) and ( m_{2} ) are connected by spring constant ( boldsymbol{K} ) Initially the spring is at its natural length. The coefficient of friction between the bars and the surface is ( mu ) What minimum constant force has to be applied in the horizontal direction on the block of mass ( m_{1}, ) in order to shift the other block? ( A ) [ F=muleft(2 m_{1}+frac{m_{2}}{2}right) g ] В ( cdot F=muleft(2 m_{1}+m_{2}right) g ) ( ^{mathbf{c}} cdot_{F}=muleft(m_{2}+frac{m_{1}}{2}right) g ) ( ^{mathrm{D}} F=muleft(m_{1}+frac{m_{2}}{2}right) g ) |
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| 541 | If the net external force on a body is zero, its acceleration: A. must be equal to zero B. may be equal to zero c. must be non-zero D. must be equal to ( g ) |
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| 542 | If ( A ) and ( B ) are two objects with masses 100 kg and 200kg respectively, then which object will have less inertia? A . ( 200 k g ) в. ( 100 k g ) c. Both D. None |
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| 543 | Mark the correct statements about the friction between two bodies. This question has multiple correct options A. Static friction is always greater than the kinetic friction. B. Coefficient of static friction is always greater than the coefficient of kinetic friction. C. limiting friction is always greater than the kinetic friction. D. limiting friction is never less than static friction. |
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| 544 | A solid sphere is placed on a smooth horizontal plane. A horizontal impluse ( I ) is applied at a distance ( h ) above the central line as shown in the figure. Soon after giving the impulse the sphere starts rolling. The ratio ( h / R ) would be A . 1 2 B. 2 5 ( c cdot frac{1}{4} ) D. 1 |
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| 545 | ‘The action and reaction are equal in magnitude’. Is this statement true and which law is related with it? A. Yes, Newton’s second law B. Yes, Newton’s third law c. No, Newton’s third law. D. Yes, Newton’s first law. |
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| 546 | A horizontal force of ( 500 N ) pulls two masses ( 10 k g ) and ( 20 k g ) connected by a light string and placed on a frictionless horizontal table. What is the tension in the string if the force is applied on the ( 20 k g ) mass? A. ( 333.3 N ) N в. ( 166.7 N ) c. ( 233.3 N ) D. ( 217 N ) |
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| 547 | 2. A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle. The motion of the particle takes place in a plane. It follows that (IIT JEE, 1987) a. Its velocity is constant b. Its acceleration is constant c. Its kinetic energy is constant d. It moves in a circular path |
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| 548 | The acceleration of blocks B is: A. zero B. ( 3.336 m / s^{2} ) c. ( 4.11 mathrm{m} / mathrm{s}^{2} ) D. ( 2.943 m / s^{2} ) |
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| 549 | An example of rolling friction is: A. using oil to lubricate B. skateboard moving on wheels C. dragging your sister across floor on a blanket D. a fish swimming through ocean |
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| 550 | Two particles ( A ) and ( B ) each of mass ( m ) are attached by a light inextensible string of length ( 2 l . ) The whole system lies on a smooth horizontal table with ( boldsymbol{B} ) initially at a distance ( l ) from ( A ). The particle at end ( B ) is projected across the table with speed ( u=4 sqrt{3} m / s ) perpendicular to ( A B ). Find velocity of ball ( A ) just after the jerk? |
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| 551 | Find force ( boldsymbol{F} ) required to keep the system in equilibrium. The dimensions of the system are ( boldsymbol{d}=mathbf{0 . 3 m} ) and ( boldsymbol{a}= ) ( 0.2 m . ) Assume the rods to be massless A . ( 150 mathrm{N} ) B. -150 N c. ( 100 mathrm{N} ) D. It cannot be in equilibrium |
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| 552 | 54. If the acceleration of wedge in the shown arrangement is a ms towards left, then at this instant, acceleration of the block (magnitude only) would be Fig. 6.336 a. 4a ms-2 b. a /17 – 8 cos a ms-2 c. (ſ17)ams? d. 117 cos xams 2 |
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| 553 | There are three Newton’s laws of motion namely first,second and third laws.We can derive A. Second and third laws from the first law B. First and second laws from the third law c. Third and first laws from the second law D. All the three laws are independent of each other |
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| 554 | ( S I ) units of momentum is A ( cdot k g m / s^{2} ) в. ( k g m / s ) ( mathbf{c} cdot g k m / h r ) D. ( k g k m / h r ) |
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| 555 | Assertion A cricket player while catching a bal lowers his hands to save himself from getting hurt. Reason The impulsive force on hands is reduced by increasing the time of action. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
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| 556 | 7. Maximum force Fo exerted by the bat on the bal. a. 4000 N b. 5000 N c. 3000 N d. 2500 |
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| 557 | State whether true or false. Newton’s first law of motion gives the concept of momentum. A. True B. False |
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| 558 | Coefficients of friction between the flat bed of the truck and crate are ( mu_{s}=0.8 ) and ( mu_{k}=0.7 . ) The coefficient of kinetic friction between the truck tires and the road surface is ( 0.9 . ) If the truck stop from an initial speed ( 15 m / s ) with maximum braking (wheels skidding). Determine where on the bed the crate finally comes to rest. (Take ( g=10 m / s^{2} ) ( mathbf{A} cdot 2.77 m ) B. 2.37 т ( c .3 m ) D. ( 1.77 m ) |
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| 559 | Fill in the blank. Dynamic Fluid Friction is the sliding friction of solids. A. higher than B. lower than c. same as D. higher than or equal to |
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| 560 | In the figure, a block of weight ( 60 N ) is placed on a rough surface. The coefficient of friction between the block and the surface is ( 0.5 . ) What should be the weight ( W ) such that the block does not slip on the surface? |
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| 561 | in of m, and my a = 8 SI U Illustration 6.26 If the pulley is massless and moves an upward acceleration an, find the acceleration of m. w.r.t. to elevator. m2 Fig. 6.76 |
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| 562 | 30. The value of a, is a. F F ₂ . F – F z c. F + F2 d. F + F2 my + m₂ m₂ m₂ m₂ m₂ m₂ + m₂ |
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| 563 | A chain lies on a rough horizontal table. It starts sliding when one-fourth of its length hangs over the edge of the table. The coefficient of static friction between the chain and the surface of the table is: A ( cdot frac{1}{2} ) B. ( frac{1}{3} ) ( c cdot frac{1}{4} ) D. 1 ( overline{5} ) |
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| 564 | State whether given statement is True or False. Are forces acting on block actionreaction pair. A. True B. False |
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| 565 | Newton’s Third law is equivalent to the: A. law of conservation of linear momentum B. law of conservation of angular momentum C. law of conservation of energy D. law of conservation of energy and mass |
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| 566 | A filled shopping cart ( (30.0 k g) ) is being pushed rapidly toward the back of a store so that its velocity is ( -2.0 m / s ) What is the momentum of the cart, and what is the kinetic energy of the cart?? A. Momentum ( 60.0(k g)(m) / s ), Kinetic energy ( 60.0 J ) B. Momentum ( -60.0(k g)(m) / s ), Kinetic energy 60.05 c. Momentum ( 60.0(k g)(m) / s ), Kinetic energy -60.0 . D. Momentum ( -60.0(k g)(m) / s ), Kinetic energy ( -60.0 J ) E. Momentum ( 60.0(k g)(m) / s, ) Kinetic energy ( 120.0 J ) |
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| 567 | If a rigid body is subjected to two forces ( vec{F}_{1}=2 hat{i}+3 hat{j}+4 hat{k} ) acting at (3,3,4) and ( overrightarrow{boldsymbol{F}}_{2}=-2 hat{boldsymbol{i}}-boldsymbol{3} hat{boldsymbol{j}}-boldsymbol{4} hat{boldsymbol{k}} ) acting at (1,0,0) then which of the following is (are) true? A. The body is in equilibriumm B. The body is under the influence of a torque only C. The body is under the influence of a single force D. The body is under the influence of a force together with torque |
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| 568 | A uniform cylinder rests on a cart as shown. The coefficient a static friction between the cylinder and the cart is 0.5 fthe cylinder is ( 4 mathrm{cm} ) in diameter and ( 10 mathrm{cm} ) in height, then what is the minimum acceleration ( left(text { in } m s^{-2}right) ) of the cart needed to cause the cylinder to tip over? |
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| 569 | The weight of an object: A. is the quantity of the matter it contains B. refers to its inertia C. is the same as its mass but is expressed in different unit D. is the force with which it is attracted towards the earth |
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| 570 | ( mathbf{A} ) 1 kg body slides from the point ( A ) (see figure), along a horizontal track with an initial speed of ( 6 m s^{-1}, ) towards a weightless horizontal spring of length ( 2 m ) and force constant ( 4 N m^{-1} ). The part ( A B ) of the track is frictionless and the part ( B C ) has the coefficients of static and dynamic friction as 0.22 and ( 0.2, ) respectively. Find the total distance through which the block moves, before it comes to rest completely ( .(g= ) ( 10 m s^{-2} ) ), if ( A B=4 m ) and ( B D= ) ( mathbf{4 . 2 8 m} ) |
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| 571 | A car moves on a horizontal track of radius ( r, ) the speed increasing constantly at rate ( frac{boldsymbol{d} boldsymbol{v}}{boldsymbol{d} boldsymbol{t}}=boldsymbol{a} . ) The coefficient of friction between road and tyre is ( mu . ) Find the speed at which the car will skid. A ( cdotleft[left(mu^{2} g^{2}+a^{2}right) r^{2}right]^{1 / 4} ) B . ( sqrt{mu g r} ) ( ^{mathrm{C}} cdotleft[left(mu^{2} g^{2}-a^{2}right) r^{2}right]^{1 / 4} ) D. ( sqrt{a r} ) |
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| 572 | Choose the correct statement. A. weight is a vector quantity B. the weight of a body in interplanetary space is maximum C. weight increases with height from the earth surface D. ( 1 N=1 k g times 1 m / s ) |
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| 573 | In which of the following cases the net force is not equal to zero? A. A kite skillfully held stationary in the sky. B. A ball falling freely from a height. c. A helicopter hovering above the ground. D. A cork floating on the surface of water. |
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| 574 | In the given arrangement, mass of the block is ( mathrm{M} ) and the surface on which the block is placed is smooth. Assume all pulleys to be massless and frictionless, strings to be inelastic and light, ( boldsymbol{R}_{1}, boldsymbol{R}_{2} ) and ( R_{3} ) to be light supporting rods. The acceleration of point ( mathrm{P} ) will be (A is fixed) : ( A cdot O ) B. ( infty ) c. ( frac{4 F}{M} ) D. ( frac{2 F}{M} ) |
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| 575 | The momentum of a ( 10 mathrm{kg} ) body moving at ( 36 mathrm{km} / mathrm{h} ) is: A. ( 100 mathrm{kg} . mathrm{m} / mathrm{s} ) B. 360 kg. m/s c. ( 3.6 mathrm{kg}, mathrm{m} / mathrm{s} ) D. 36000 kg.m /s |
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| 576 | Which friction comes into play when we try to move an object at rest? A. Rolling friction B. Fluid friction c. sliding friction D. Static friction |
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| 577 | A curved section of a rod is banked for a speed ( v ). If there is no friction between road and tyres of the car, then: A. car is more likely to slip at speeds higher than ( v ) than speeds lower than ( v ) B. car cannot remain in static equilibrium on the curved section c. car will not slip when moving with speed ( v ) D. None of the above |
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| 578 | 51. When the block reaches point B, what is the direction (in terms of angle with horizontal) of acceleration of the block? a. tan b. tan-‘(2) d. The block never reaches point B. |
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| 579 | 10. The tension in the string is a. 1.5mg b. 5.8mg c. 4.7mg d. 3.2mg |
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| 580 | A boy pushes a wall with a force of ( 10 N ) towards east. What force is exerted by the wall on the boy? A. ( 10 N ) towards east B. ( 10 N ) towards west c. ( 10 N ) towards north D. ( 10 N ) towards south. |
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| 581 | A man of mass ( mathrm{m} ) is applying a horizontal force to slide a box of mass ( mathrm{m}^{prime} ) on a rough horizontal surface. It is known that the man does not slide. The coefficient of friction between the shoes of the man and the floor is ( mu ) and between the box and the floor is ( mu^{prime} . ) In which of the following cases it is certainly not possible to slide the box? |
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| 582 | A rocket with a lift-off mass ( 3.5 times 10^{4} ) kg is blasted upwards with an initia acceleration of ( 10 m / s^{2} . ) Then the initial thrust of the blast is: A ( cdot 3.5 times 10^{5} N ) в. ( 7.0 times 10^{5} N ) c. ( 14.0 times 10^{5} N ) D. ( 1.75 times 10^{5} N ) |
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| 583 | A box, when hung from a spring balance shows a reading of ( 50 mathrm{kg} ). If the same box is hung from the same spring balance inside an evacuated chamber, the reading on the scale will be. A. ( 50 mathrm{kg} ) because the mass of the box remains unchanged B. ( 50 mathrm{kg} ) because the effect of the absence of the atmosphere will be identical on the box and the spring balance c. Less than ( 50 mathrm{kg} ) because the weight of the column of air on the box will be absent D. More than 50kg because the atmospheric buoyancy force will be absent |
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| 584 | The driver of a car traveling at velocity ( v ) suddenly sees a broad wall in front of him at a distance ( a ). He should A. break sharply B. turn sharply ( c . ) both a and ( b ) D. none of the above |
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| 585 | Blocks A and B are connected as shown in figure. Find the relation between acceleration of block ( A ) and ( B ) A ( cdot a_{A}=2 a_{B} ) В . ( a_{B}=2 a_{A} ) ( c cdot a_{4}=4 a_{B} ) |
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| 586 | The term ‘mass’ is analogous to physical quantity A. Weight B. Inertia c. Force D. Acceleration |
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| 587 | Choose the correct statement(s) A. Motion necessarily takes place along the direction of force B. If no force acts, the body is at rest C. ( A ) body in motion, need not be acted upon by a force D. A change in speed is always there, whenever a force is applied on the moving body |
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| 588 | A spool of mass ( M ) and radius ( 2 R ) lies on an inclined plane as shown in figure. A light thread is wound around the connecting tube of the spool and its free end carries a weight of mass ( m ). The value of ( m ) so that system is in equilibrium is ( A cdot 2 M sin alpha ) B. ( M sin alpha ) ( c .2 M tan alpha ) D. ( M tan alpha ) |
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| 589 | 2. Just after burning the thread, what is the tension in the spring? a. m18 b. m28 c. Zero d. Cannot say __ _ |
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| 590 | If a particle of mass m moving with velocity ( v_{1} ) is subject to an impulse ( I ) which produces a final velocity ( v_{2}, ) then ( boldsymbol{I} ) is given by : B. ( mleft(v_{1}+v_{2}right) ) c. ( mleft(v_{2}-v_{1}right) ) D. ( frac{mleft(v_{2}^{2}-v_{1}^{2}right)}{2} ) |
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| 591 | The pulleys and strings shown in the fig are smooth and of negligible mass. For the system to remain in equilibrium, the angle ( theta ) should be: ( A cdot 0^{circ} ) B. ( 30^{circ} ) ( c cdot 45^{circ} ) D. ( 60^{circ} ) |
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| 592 | 6. The extra force required to keep the belt moving is a. 0.4 N b. 0,08 N c. 0,04 N d. 02 N |
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| 593 | ( A ) and ( B ) are two objects with mass 6 kg and 34 kg respectively. Then A. A has more inertia than ( B ) B. B has more inertia than A c. A and B both have same inertia D. none of the above is true |
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| 594 | Two ( 30 mathrm{kg} ) blocks rest on a massless belt which passes over a fixed pulley and is attached to a 40 kg block. If coefficient of friction between the belt and the table as well as between the belt and the blocks ( mathrm{B} & ) block ( mathrm{C} ) is ( mu . ) The system is released from rest from the position shown, the speed with which the block ( mathrm{B} ) falls off the belt is This question has multiple correct options ( mathbf{A} cdot 2 sqrt{2} m / s ) if ( mu=0.2 ) B. ( 2 m / s ) if ( mu=0.2 ) ( c: quad ) । ( / s ) if ( mu=0.5 ) D. ( 2.5 m / s ) if ( mu=0.5 ) |
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| 595 | During a planned manoeuvre in a space flight, a free-floating astronaut ( A ) pushes another free floating astronaut B, the mass of A being greater than that of B. Then, the magnitude of the force exerted by astronaut A on astronaut B is: A. equal to zero B. equal to the force exerted by B on A c. greater than the force exerted by B on A D. less than the force exerted by B on A |
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| 596 | tration 7.44 A car of mass m moving over a convex ge of radius r. Find the normal reaction acting on car when it is at the highest point of the bridge. bridge of radius |
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| 597 | A glass marble, whose mass is ( 100 g m ) falls from a height of ( 20 m ) and rebounds to a height of 5 m. Find the impulse and average force between the marble and the floor, if the time during which they are in contact is 0.01 sec. |
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| 598 | The momentum of a massive object at rest is i) very large ii) very small iii) zero iv infinity |
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| 599 | Which of the following statements is/are correct for internal forces? A. They are always balancedd B. They are never balanced c. They may or may not be balanced D. none of these |
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| 600 | 12. Statement I: The greater the rate of the change in the momentum vector, the greater the force applied. Statement II: Newton’s second law is F = dt |
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| 601 | A body of mass 400 g slides on a rough horizontal surface. If the frictional force is ( 3.0 mathrm{N} ). Find the angle made by the contact force on the body with the vertical. A ( .37^{circ} ) В. ( 53^{circ} ) ( c cdot 63^{0} ) D. ( 27^{circ} ) |
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| 602 | A body of mass ( m ) rests on a horizontal plane with a friction coefficient ( mu ). At ( t=0, ) a horizontal force is applied ( (F= ) ( a t) ) where ( a ) is a constant vector. Find the distance traversed in first ( t ) sec. ( ^{mathbf{A}} cdot frac{a}{6 m}left(t-frac{mu m g}{a}right)^{3} ) в. ( frac{a}{6 m} t^{3} ) c. ( frac{a}{6 m} t^{3}-frac{mu g t^{2}}{2} ) D. ( frac{a}{6 m} t^{3}-frac{mu g t^{2}}{3} ) |
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| 603 | If the same force is applied on two bodies of different masses for the same time, then the change produced in the momentum of the two bodies is also same A. True B. False |
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| 604 | A bob is suspended from the ceiling of a car which is accelerating uniformly on a horizontal road choose the wrong statement A. the bob stays a constant angle ( theta ) with vertical with respect to car in equilibirum B. the magnitude linear momentum of a bob as seen from the rod is increasing with time c. linear momentum is conserved only in car reference of frame D. linear momentum is conserved in car as well as ground reference of frame |
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| 605 | What is drag? A. Frictional force offered by fluids B. Friction force offered by a solid surface C . Pulling a body over a surface D. None of these |
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| 606 | Mark the correct option A. The state of motion of an object is described by its speed only B. Many a time application of force does not result in a change in the state of motion of an object C. By sitting on a bicycle seat force is applied to the spring fixed to the seat of a bicycle D. All of the above |
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| 607 | A man of mass ( M ) is standing on a plank kept in a box. the plank and box as a whole has mass ( boldsymbol{m} . ) A light string passing over a fixed smooth pulley connects the man and box. If the box remains stationary, find the tension in the force exerted by the man on the plank. |
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| 608 | A particle of mass m strikes a horizontal smooth floor with a velocity u making an angle ( theta ) with the floor and rebounds with velocity v making an angle ( phi ) with the floor. The coefficient of restitution between the particle and the floor is e. Then A. the impluse delivered by the floor to the body is ( m u(1-e) sin theta ) B. ( tan phi=operatorname{etan} theta ) c. ( v=u sqrt{1-left(1+e^{2}right) sin ^{2} theta} ) D. the ratio of the final kinetic energy to the initial kinetic energy is ( cos ^{2} theta+operatorname{esin}^{2} theta ) |
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| 609 | 11. Acceleration of block C is a. 1/4 ms2 b. 2/7 ms-2 c. 5/4 ms-2 d. 1/3 ms-2 |
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| 610 | A man tries to remain in equilibrium, This question has multiple correct options A. he must exert equal forces on the two walls B. the forces of friction at the two walls must be equal. C. friction must be present on both walls D. the coefficients of friction must be the same between both walls and the man |
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| 611 | L to Rod In Fig. 6.390, a block of mass m is relea from rest when spring was in its natural length. The pulley also has mass m but it is String frictionless. Suppose the value of mis such that finally it is just able to lift block M up after releasing it. Fig. 6.390 Column I Column II Weight of m required to just lift M M 2 b. Mg Tension in the rod, when m is in equilibrium Normal force acting on M when m is in equilibrium. d. 2 mg Tension in the string when displacement of mis maximum possible |
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| 612 | 20 wolley T of mass 5 kg on a horizontal smooth surface is pulled by a load of 2 kg through a uniform rope ABC OI ngth 2 m and mass 1 kg. As the load falls from BC = 0 to BC = 2 m, its acceleration (in ms-2) changes from TA B (0) 2 kg Fig. 6.299 d. None of these |
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| 613 | A body of mass ( 2 k g ) is sliding with a constant velocity of ( 4 m / s ) on a frictionless horizontal table. The net force required to keep the body moving with the same velocity is A. ( 8 N ) в. ( 0 N ) c. ( 4 N ) D. ( frac{1}{2} N ) |
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| 614 | sliding along its length on a horizontal table whose top is partly smooth and rest roughly with friction coefficient ( mu . ) If the rod after moving through the smooth part enters the rough with velocity ( boldsymbol{v}_{mathbf{0}} ) (i) What will be the magnitude of the friction force when its ( x ) length ( (<L) ) lies in the rough part during sliding. (ii) Determine the minimum velocity ( boldsymbol{v}_{mathbf{0}} ) with which it must enter so that it lies completely in a rough region before coming to rest. (iii) If the velocity is double the minimum velocity as calculated in part (a) then what distance does its front end ( A ) would have travelled in a rough region before rod comes to rest. |
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| 615 | Which of the following statements is correct about friction? A. The coefficient of friction between a given pair of substances is largely independent of the area of contract between them. B. The frictional force can never exceed the reaction froce on the body from the support surface. C. Rolling friction is only slighting smaller than sliding friction. D. The main source of friction is the irregularity of the surface in contact. |
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| 616 | A hockey player is moving northward and suddenly turns westward with the same speed to avoid an opponent The force that acts on the player is A. Frictional force along westward B. Muscle force along southward c. Frictional force along south-west D. Muscle force along south-west |
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| 617 | 2. A block of mass m = 2 kg is resting on a rough inclined plane of inclination 30° as shown in Fig. 7.353. The coefficient of friction between the block and the plane is u = 0.5. What minimum force F (in newton) should be applied perpendicular to the plane on the block, so that the block does not slip on the plane? 370 |
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| 618 | 2 kg Tilustration 7.24 Figure 7.69 shows two blocks in contact sliding down an inclined surface of inclination 30°. The friction coefficient between the block of mass 2 kg and the incline is Hi = 0.20 and that between the block of mass 4 kg and the incline is un=0.30. Find the acceleration of 2.0 kg block. Fig. 7.69 300 g= 10 ms-2 |
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| 619 | A vehicle of ( 100 k g ) is moving with a velocity of ( 5 m / s . ) To stop it in ( 1 / 10 s e c ) required force in opposite direction is ( N ) A . 50 в. 500 c. 5000 D. 1000 |
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| 620 | resting on a smooth horizontal ground attached to one end of a spring of force constant ( k ) in natural length. If another block of same mass and moving with a velocity u toward right is placed on the block which stick to it due to friction. The time it will take to reach its extreme position. Also find the amplitude of oscillations of the combined mass ( 2 mathrm{m} ) ( ^{mathbf{A}} cdot A=sqrt{frac{m}{2 k}}, t=sqrt{frac{k}{2 m}} ) В. ( A=u sqrt{frac{m}{2 k}}, t=frac{pi}{2} sqrt{frac{2 m}{k}} ) c. ( A=sqrt{frac{u m}{2 k}}, t=pi sqrt{frac{2 m}{k}} ) D. none of these |
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| 621 | Momentum is a ( _{-}-_{-}-_{-}-_{-} ) quantity Fill in the blank. A. scalar B. vector c. tensor D. none |
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| 622 | Friction is a that opposite motion? A. True B. False |
11 |
| 623 | State whether true or false. Newton’s second law gives the measure of force. A. True B. False |
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| 624 | State and prove the law of conservation of momentum. |
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| 625 | The correct statement of third law is: A. The rate of change of momentum of an object is directly proportional to the applied force B. For every action there is an equal and opposite reaction C. An object at rest stays at rest and an object in motion stays in motion unless acted upon by an unbalanced force D. None of these |
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| 626 | v V, and moves 17. In Fig. 6.306, the mass m starts with velocity ve and with constant velocity on the surface. During motion normal reaction between the horizontal surface and triangle block m, is N. Then during motion ce and fixed ma mi 1 A a. N=(mi + m)g c. N(m, + m2) g |
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| 627 | A Diwali rocket is ejecting ( 0.05 k g ) of gases per second at a velocity of ( 400 m s^{-1} . ) The repulsive force on the rocket is A. 20 dyne B. 20 newton c. 20 kgwt D. Sufficient data not given |
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| 628 | A machine gun fires a bullet of mass ( 40 g ) with a velocity ( 1200 m s^{-1} . ) The man holding it can exert a maximum force of 144N on the gun. How many bullets can he fire per second at the most? A. ( O n e ) B. Four c. ( T w o ) D. Three |
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| 629 | Assertion Static frictional force is self adjusting, for the given two surfaces. Reason Sliding frictional force between two given solid surfaces is independent of surface area of contact A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
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| 630 | The inertial force acts in a A. Opposite direction to that of acceleration force B. Same direction as that of accelerating force C. Perpendicular direction to that accelerating force D. None of the above |
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| 631 | 13. A man is raising himself and the crate on which he stands with an acceleration of 5 ms 2 by a massless rope-and- pulley arrangement. Mass of the man is 100 kg and that of the crate is 50 kg. If g = 10 ms-2, then the tension in the rope is Fig. 6.303 b. 1125 N c. 750 N a. 2250 N d. 375 N |
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| 632 | The weight of 50 kg person at the surface of earth is A . ( 50 N ) B. ( 35 N ) c. ( 380 N ) D. ( 490 N ) |
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| 633 | A flexible chain of length I and mass ( mathrm{m} ) is slowly pulled at constant speed up over the edge of a table by a force ( F ) parallel to the surface of the table. Assuming that there is no friction between the table and chain, calculate the work done by force ( F ) till the chain reaches to the horizontal surface of the table. |
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| 634 | Explain why sportsmen use shoes with spikes. | 11 |
| 635 | A force-time graph for a linear motion is shown in the figure where the segments are circular. The linear momentum gained between zero and 8 second is : A . ( -2 pi ) Newton seconds B. 0 Newton seconds c. ( 4 pi ) Newton seconds D. ( -6 pi ) Newton seconds |
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| 636 | An object is in equilibrium under four concurrent forces in the directions shown in figure. Find the magnitudes of ( vec{F}_{1} ) and ( vec{F}_{2} ) |
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| 637 | Assertion Frictional force is independent of the velocity of the body Reason Friction is due to surface irregularities. A. both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. both Assertion and Reason are incorrect |
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| 638 | If force ( F=(500-100) t, ) then impulse as a function of time will be:- ( mathbf{A} cdot 500 t-50 t^{2} ) B . ( 50 t-10 ) c. ( 50-t^{2} ) D. ( 100 t^{2} ) |
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| 639 | A car weighs 1800 kg. The distance between its front and back axles is 1.8 m. Its centre of gravity is 1.05 m behind the front axle. Determine the force exerted by the level ground on each front wheel and each back wheel. |
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| 640 | State Newton’s third law of motion. | 11 |
| 641 | If a body is acted upon by a constant force then it will have a uniform A. velocity B. acceleration c. inertia D. momentum |
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| 642 | Find the weight of a box on earth having a mass of ( 20 mathrm{kg} ) ( A cdot 196 N ) B. 19.6 N c. ( 1.96 mathrm{N} ) D. 0.19 N |
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| 643 | A block of mass ( m ) slides down an inclined plane of inclination ( theta ) with uniform speed. The coefficient of friction between the block and the plane is ( mu . ) The contact force between the block and the plane is ( mathbf{A} cdot m g sin theta sqrt{1+mu^{2}} ) B. ( sqrt{(m g sin theta)^{2}+(mu m g cos theta)^{2}} ) ( mathrm{c} cdot m g sin theta ) D. ( m g ) |
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| 644 | wheels 5. A car is moving in a circular horizontal track of radius 10 m with a constant speed of 10 ms.A plumb bob is suspended form the roof of the car by a light rigid rod. The angle made by the rod with the vertical is (IIT JEE, 1992) a. Zero b. 30° c. 45º d . 60° |
11 |
| 645 | A ball reaches a racket at ( 60 mathrm{m} / mathrm{s} ) along ( +X ) direction, and leaves the rocket in the opposite direction with the same speed. Assuming that the mass of the ball as ( 50 mathrm{gm} ) and the contact time is 0.02 second, the force exerted by the racket on the ball is A. 300 N along + X direction B. 300 N along – X direction c. ( 3,00,000 mathrm{N} ) along ( +mathrm{x} ) direction D. 3,00,000 N along – X direction |
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| 646 | A ( 150 g ) cricket ball moving at a speed of ( 12 m / s ) is hit by a bat and turned back at a speed of ( 20 m / s . ) The duration of impact is ( 0.1 s . ) What is the average force exerted on the ball by the bat? |
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| 647 | A car is travelling along a circular curve that has a radius of ( 50 mathrm{m} ). If its speed is ( 16 mathrm{m} / mathrm{s} ) and is increasing uniformly at ( 8 m / s^{2}, ) determine the magnitude of its acceleration at this instant. A ( cdot 9.5 mathrm{m} / mathrm{s}^{2} ) В. ( 9.8 mathrm{m} / mathrm{s}^{2} ) c. ( 8.5 mathrm{m} / mathrm{s}^{2} ) D. ( 7.5 mathrm{m} / mathrm{s}^{2} ) |
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| 648 | S.I. unit of momentum is : A. ( k g . m s^{-1} ) в. ( k g . m g^{-2} ) ( mathrm{c} cdot k g, m g^{2} ) D. ( k g, m^{-1} s^{-1} ) |
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| 649 | 27. A particle of small mass m is joined to a very heavy body by a light string passing over a light pulley. Both bodies are free to move. The total downward force on the pulley is a. >> mg b. 4mg c. 2mg d. mg 28 An obiect is suspended from noring bolonce in a lift The |
11 |
| 650 | ‘The action and reaction both act simultaneously.’ Is this statement true and what is the net force? A. yes, zero B. no, zero c. yes, positive D. no, negative |
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| 651 | Two blocks of masses ( mathrm{m} ) and ( mathrm{M} ) are connected by means of a metal wire passing over a frictionless fixed pulley. The area of a cross-section of the wire is ( 6.5 times 10^{-9} m^{2} ) and its breaking stress is ( 2 times 10^{9} N m^{-2} . ) If ( m=1 mathrm{kg}, ) then calculate the maximum value of ( mathrm{M}left(mathrm{g}=10 mathrm{m} / mathrm{s}^{2}right) ) ( A cdot 2 ) B. 3 ( c cdot 4 ) D. 5 |
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| 652 | If the tension in the cable supporting an elevator is equal to the weight of the elevator, the elevator may be This question has multiple correct options A. Going up with increasing speed B. Going down with increasing speed c. Going up with uniform speed D. Going down with uniform speed |
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| 653 | A uniform solid cylinder is rolling down a rough inclined plane of inclination ( boldsymbol{theta} ) Then? |
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| 654 | In which of the following cases more friction is desirable? A. Movement of piston in a cylinder B. Braking of a vehicle c. Running on a track D. All of the above |
11 |
| 655 | A uniform bar of mass ( m ) is supported by a pivot at its top about which the bar can swing like a pendulum. If a force ( boldsymbol{F} ) is applied perpendicular to the lower end of the bar as shown in figure, what is the value of ( F ) in order to hold the bar in equilibrium at an angle ( (theta) ) from the vertical ( mathbf{A} cdot 2 m g sin theta ) в. ( m g sin theta ) ( c . m g cos theta ) ( D ) |
11 |
| 656 | f the tension in the string in the figure is ( 16 mathrm{N} ) and the acceleration of each bock is ( 0.5 m / s^{2}, ) find the friction coefficients at the to contacts with the blocks. |
11 |
| 657 | A railway track is banked for a speed ( mathbf{v} ) by making the height of the outer rail h higher than that of the inner rail. The distance between the rails is d. The radius of curvature of the track is ( r ) Then, ( mathbf{A} cdot frac{h}{d}=frac{v^{2}}{r g} ) B. ( tan left(sin ^{-1} frac{h}{d}right)=frac{v^{2}}{r g} ) ( ^{mathbf{C}} tan ^{-1}left(frac{h}{d}right)=frac{v^{2}}{r g} ) ( mathbf{D} cdot frac{h}{r}=frac{v^{2}}{d g} ) |
11 |
| 658 | If a train is retarding and at same time coin is thrown upwards, then you will observe that: A. the coin reaches again in your hand B. the coin falls behind you c. the coin falls in front of you D. the coin follows a circular path |
11 |
| 659 | Suppose you want to negotiate a curve with a radius of 50 meters and a bank angle of 15 degrees. If the coefficient of friction between your tires and the pavement is ( 0.50, ) what is the maximum speed that you can safely use? A. ( 30 mathrm{m} / mathrm{s} ) B. ( 5 mathrm{m} / mathrm{s} ) c. ( 21 mathrm{m} / mathrm{s} ) D. ( 10 mathrm{m} / mathrm{s} ) |
11 |
| 660 | 90. A block of mass m is connected to a spring of spring constant k as shown in Fig. 8.264. The frame in which the block is placed is given an acceleration a towards left Neglect friction between the block and the frame walls. The maximum velocity of the block relative to the frame OO 000000 Fig. 8.264 d. 2a, |
11 |
| 661 | Statement I: The coefficient of friction can be greater than unity. Statement II: The force of friction is dependent on normal reaction and the ratio of force of friction and normal reaction cannot exceed unity. |
11 |
| 662 | A body of mass ( 5 k g ) is acted upon by two perpendicular forces of ( 8 N ) and ( 6 N ) find the magnitude of acceleration? A ( cdot 1 mathrm{m} / mathrm{s}^{2} ) в. ( 3 m / s^{2} ) ( mathrm{c} cdot 4 mathrm{m} / mathrm{s}^{2} ) D. ( 2 m / s^{2} ) |
11 |
| 663 | The tension force between two block is: A ( .10 N ) ( B cdot frac{8}{3} N ) ( c .8 N ) D. zero |
11 |
| 664 | Three charged particles are collinear and are in equilibrium, then A. all the charged particle have the same poarity B. the equilibrium is unstable C. all the charged particles cannot have the same polarity D. both (b) and (c) are correct. |
11 |
| 665 | A ball of mass 100 g moving with a speed of ( 4 mathrm{m} / mathrm{sec} ) strikes a horizontal surface at an angle of ( 30^{circ} ) from the surface. The ball is reflected back with same speed and same angle of reflection find (a) The impulse imparted to the ball (b) change in magnitude of momentum of the ball. |
11 |
| 666 | limiting friction is slightly greater than friction. | 11 |
| 667 | 55. In the arrangement shown in Fig. 6.337 at a particular instant, the roller is coming down with a speed of 12 ms and C is moving up with 4 ms. At the same instant, it is also known that wrt. pulley P, block A is moving down with speed 3 ms. Determine the motion of block B (velocity) w.rt.ground, 200 12 m 4 m Fig. 6.337 a. 4 m in downward direction b. 3 ms’in upward direction c. 7 ms’in downward direction d. 7ms in upward direction |
11 |
| 668 | The acceleration produced in a body by a force of given magnitude depends on: A. size of the body B. shape of the body c. mass of the body D. none of these |
11 |
| 669 | Ball bearings reduce friction because they – – – – rather than slide. A . roll ( l ) B. swing c. bounce D. None of the above |
11 |
| 670 | A body is in equilibrium under the influence of a number of forces. Each force has a different line of action. The minimum number of forces required is : This question has multiple correct options A. 2 , if their lines of action pass through the centre of mass of the body B. 3, if their lines of action are not parallel. ( mathrm{c} .3 ), if their lines of action are parallel D. ( 4, ) if their lines of action are parallel and all the forces have the same magnitude |
11 |
| 671 | A triangle is formal using three wire ( A B, B C ) and ( C A ) and is placed in a vertical plane. Coefficient of friction for all three wires is same. If ( boldsymbol{w}_{1} ) and ( boldsymbol{w}_{2} ) is the work done by the friction in moving an object from ( A ) to ( B ) through ( C^{prime} ) and ( C ) respectively, then A ( cdot w_{1}=w_{2} ) в. ( w_{1}w_{2} ) D. the relation depends on the length AC and BC |
11 |
| 672 | The maximum force of friction which just allows one body to slide upon another body is called |
11 |
| 673 | Which of the following are done to reduce friction? a) Making grooves in the shoes b) Polishing rough surfaces c) Using wheels, ball bearings d) Creating an air cushion ( A cdot a, b ) and ( c ) B. c and d ( c . b, c ) and ( d ) D. All of the above |
11 |
| 674 | A ship moving in sea can’t be stopped quickly by applying brakes due to: A . low friction B. excessive friction c. high speed D. none of the above |
11 |
| 675 | A rider on horse falls back when horse starts running, all of a sudden because: A. rider is taken back B. rider is suddenly afraid of falling c. inertia of rest keeps the upper part of body at rest while lower part of the body moves forward with the horse D. none of the above |
11 |
| 676 | 84. Two bodies of masses m and 4m are attached to a light string as shown in Fig. 8.262. A body of mass m hanging from string is executing oscillations with angular amplitude 60°, while other body is at rest on a horizontal surface. The minimum coefficient of friction between mass 4m and the horizontal surface is (here pulley is 18 and smooth) 4 m Fig. 8.262 OCCO movie with a velit. f 24 1m-1 |
11 |
| 677 | The taxi driver has to be more careful when driving car in winter because of morning dew. That means the friction on road during winter is friction during summer. Fill in the blank. A. more than B. less than c. same as D. having no relation with |
11 |
| 678 | An insect crawls up a hemispherical surface. The coefficient of friction between the insect and the surface is 1/3. If the line joining the centre of the hemispherical surface to the insect makes an angle ( alpha ) with the vertical, the maximum possible value of ( alpha ) is given by A. ( cot alpha=3 ) B. ( tan alpha=3 ) c. ( sec alpha=3 ) D. ( operatorname{cosc} alpha=3 ) |
11 |
| 679 | net acceleration of block ( mathrm{B}, ) when extension in the spring is ( boldsymbol{x}=frac{boldsymbol{x}_{boldsymbol{m}}}{boldsymbol{4}} ) A ( cdot frac{g}{2}(text {downwards}) ) B. ( frac{g}{3}(text {downwards}) ) c. ( frac{g}{4}(text {downwards}) ) D. ( frac{g}{6}(text {downwards}) ) |
11 |
| 680 | The maximum safe speed for a vehicle taking a turn on a curved banked road, does not depend upon A. acceleration due to gravity B. mass of the vehicle c. angle of inclination with the horizontal D. radius of curvature of the track |
11 |
| 681 | 13 LUN! 18 = IU ms ). 6. In Fig. 7.244, find the acceleration of m assuming ere is friction between m and M, and all other surface are smooth and pulleys light and u=coefficient of friction between m and M. Fig. 7.244 |
11 |
| 682 | A force of ( 10 mathrm{N} ) acts on a body for 3 microsecond ( (mu mathrm{s}) . ) If mass of the body is ( 6 mathrm{g} ), calculate the change of velocity. ( mathbf{A} cdot 26 times 10^{-2} m s^{-1} ) B . ( 16 times 10^{-3} mathrm{m} mathrm{s}^{-1} ) C ( .5 times 10^{-3} mathrm{m} mathrm{s}^{-1} ) D. ( 36 times 10^{-2} mathrm{m} mathrm{s}^{-1} ) |
11 |
| 683 | A body of mass ( 5 k g ) undergoes a change in speed from 20 to ( 0.20 m / s . ) The momentum of the body would A. Increase by ( 99 k g m / s ) B. Decrease by ( 99 mathrm{kgm} / mathrm{s} ) c. Increase by ( 101 mathrm{kgm} / mathrm{s} ) D. Decrease by ( 101 mathrm{kgm} / mathrm{s} ) |
11 |
| 684 | Two masses ( M_{1} ) and ( M_{2} ) are attached to the end of a light string which passes over a massless pulley attached to the top of a double inclined smooth plane of angles of inclination ( boldsymbol{alpha} ) and ( boldsymbol{beta} ). If ( boldsymbol{M}_{mathbf{2}}> ) ( M_{1} ) and ( beta>alpha ) then the acceleration of block ( M_{2} ) down the inclined will be: A ( cdot frac{M_{2} g(sin beta)}{M_{1}+M_{2}} ) В. ( frac{M_{1} g(sin alpha)}{M_{1}+M_{2}} ) ( c ) D. Zero |
11 |
| 685 | The weight of an object A. is the quantity of the matter it contains B. refers to its inertia C. is same as its mass but is expressed in different units D. is the force with which it is attracted towards the earth |
11 |
| 686 | A weightless string passes through a slit over a pulley. The slit offers frictional force ( boldsymbol{f} ) to the string. The string carries two weights having masses ( boldsymbol{m}_{1} ) and ( boldsymbol{m}_{2} ) where ( boldsymbol{m}_{2}>boldsymbol{m}_{1} ) then acceleration of the weights is: A ( cdot frac{left(m_{2}-m_{1}right) g-f}{m_{1}+m_{2}} ) B. ( frac{f-left(left(m_{2}-m_{1}right) gright.}{left(m_{1}+m_{2}right)} ) C ( cdot frac{left(m_{1}+m_{2}right) g-f}{m_{1}-m_{2}} ) D. ( frac{m_{2} g-f}{left(m_{1}+m_{2}right)} ) |
11 |
| 687 | Three identical blocks, each of mass 10 kg , are pulled as shown on the horizontal frictionless surface. If the tension (F) in the rope is ( 30 N . ) What is the acceleration of each block? And what are the tensions in the other ropes? (Neglect the masses of the ropes) |
11 |
| 688 | In the adjoining figure, the position time graph of a particle of mass ( 0.1 mathrm{kg} ) is shown. The impulse at ( t=2 s ) is : A . ( 0.02 mathrm{kgm} / mathrm{s} ) B. ( 0.1 mathrm{kgm} / mathrm{s} ) c. ( 0.2 k g m / s ) D. ( 0.4 k g m / s ) |
11 |
| 689 | Explain why some of the leaves may get detached from a tree if we vigorously shake it branch. | 11 |
| 690 | In the figure given above, the position time graph of a particle of mass ( 0.1 k g ) is shown. The impulse at ( t=2 sec ) is: A ( .0 .2 k g m s e c^{-} ) B. – ( 0.2 k g m ) sec ( ^{-1} ) c. ( 0.1 k ) gmsec ( ^{-1} ) D. – ( 0.4 k g ) msec( ^{-} ) |
11 |
| 691 | If no force acts on a body it will A. change shape B. move with increased speed C. either remain in rest or move with uniform speed D. break up |
11 |
| 692 | Assertion We can live very happily if the friction is not present in nature Reason Aeroplane shape is stream lined to reducec the effort of frictional force. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is incorrect but Reason is correct D. Both Assertion and Reason are incorrect |
11 |
| 693 | A car of mass ( M ) is moving on a horizontal circular path of radius ( r . A t ) an instant, its speed is ( boldsymbol{v} ) and is increasing at the rate ( a ). Then This question has multiple correct options A. The acceleration of the car is towards the centre of the path B. The magnitude of the frictional force on the car is greater than ( frac{m v^{2}}{r} ) C. The friction coefficient between the ground and the car is not less than a/g D. The friction coefficient between the ground and the car is ( mu=tan ^{-1} frac{v^{2}}{r g} ) |
11 |
| 694 | 37°c 1. A block is placed on an inclined plane moving towards right horizontally with 20 = an acceleration ay = g. The length of the plane AC = 1 m. Friction is absent everywhere. Find the time taken (in Fig. 6.392 seconds) by the block to reach from C to A. TLC |
11 |
| 695 | A car driver going at a speed ( mathbf{v} ) suddenly find a wide wall at a distance. (coefficient of friction is ( mu ) ) A. If the apply breaks, he will come to rest after a distance ( frac{v^{2}}{2 mu g} ) B. If he turn the cart in a circle to avoid hitting, then radius of the circle is ( frac{v^{2}}{mu g} ) C. It is better to apply breaks rather than to turn the vehicle in a circle D. It is better to turn the vehicle in a circle than to apply brakes |
11 |
| 696 | A cart of mass ( 20 mathrm{kg} ) at rest is to be dragged at a speed of ( 18 mathrm{km} mathrm{h}^{-1} ). If the co-efficient of friction between the cart and the ground is ( 0.1, ) what is the minimum force required to drag the cart to a distance of ( 10 mathrm{m} ) ? (Take ( g= ) ( left.10 m s^{-2}right) ) |
11 |
| 697 | A heavy uniform chain lies on a horizontal table top. If the coefficient of friction between the chain and the table surface is ( 0.25, ) then find the maximum ( % ) of the length of the chain that can hang over one edge of the table. A . ( 20 % ) B. 25% ( c .35 % ) D. ( 15 % ) |
11 |
| 698 | A body of weight ( 50 N ) placed on a horizontal surface is just moved by a force of ( 28.2 N . ) The frictional force and the normal reaction are A ( .10 N, 15 N ) B. ( 20 N, 30 N ) ( c cdot 2 N, 3 N ) D. ( 5 N, 6 N ) |
11 |
| 699 | A bullet of mass ( 20 g ) and moving with a velocity of ( 200 m / s ) strikes a heap of sand and comes to rest after penetrating ( 3 c m ) inside it. The force exerted by the sand on the bullet will be: ( mathbf{A} cdot 11.2 times 10^{8} d y n e ) B . ( 15.7 times 10^{8} ) dyne c. ( 13.3 times 10^{8} ) dyne D. ( 18.6 times 10^{8} ) dyne |
11 |
| 700 | The force of friction always opposes motion or the tendency of motion A. True B. False |
11 |
| 701 | Object will remain at rest or in uniform motion in a straight line unless acted upon by an external force – which law is this? A. Newton’s third law B. Newton’s first law c. Newton’s second law D. None of these |
11 |
| 702 | ( P ) and ( Q ) are two objects with masses 5kg and 30kg respectively. Then A. ( P ) has more inertia than ( Q ) B. ( Q ) has more inertia than ( P ) c. ( P ) and ( Q ) have the same inertia D. Neither ( P ) nor ( Q ) has any inertia |
11 |
| 703 | It is easy to stop a tennis ball than a cricket ball moving with the same velocity. This is because: A. tennis ball has less momentum than cricket ball B. tennis ball is soft and offers less friction c. cricket ball is hard and offers more friction D. none of these |
11 |
| 704 | Define Newton’s laws of motion. | 11 |
| 705 | th speed v against radius R kept on Illustration 7.42 A ball of mass m moves with speed ya a smooth, fixed vertical circular groove of radius R. smooth horizontal surface. Find the a. normal reaction of the floor on the ball. b. normal reaction of the vertical wall on the ball. |
11 |
| 706 | A batsman hits a cricket ball which then rolls on a level ground. After covering a short distance, the ball comes to rest. The ball slows to a stop because: A. the batsman did not hit the ball hard enough B. velocity is proportional to the force exerted on the ball C. there is a force on the ball opposing the motion D. there is no unbalanced force on the ball, so the ball would want to come to rest |
11 |
| 707 | Which Newton’s law of motion defines force? A. First B. second c. Third D. None |
11 |
| 708 | A block of mass m, connected with another block of mass m2 by a light spring of natural length 1, and stiffness k is kept stationary on a rough horizontal surface. The coefficient of friction between m, and surface is u and the block m is smooth. The block m, is moved with certain speed so as to execute uniform circular motion around the block m, in horizontal plane. Find the (a) maximum angular speed of the block m, relative to m, and (b) acceleration of m, in part (a). ാ rough smooth Fig. 7.259 |
11 |
| 709 | ( k g cdot m / s^{2} ) is the unit of A. Momentum B. Velocity c. Force D. Acceleration |
11 |
| 710 | ( A ) and ( B ) are two objects with mass ( 6 k g ) and ( 34 k g ) respectively. Then A. ( A ) has more inertia than ( B ) B. ( B ) has more inertia than ( A ) c. ( A ) and ( B ) both have same inertia D. None of the above is true |
11 |
| 711 | A rod of negligible mass having length ( l=2 m ) is pivoted at its centre and two masses of ( boldsymbol{m}_{1}=mathbf{6 k g} ) and ( boldsymbol{m}_{2}=mathbf{3 k g} ) are hung from the ends as shown in figure. (a) Find the initial acceleration of the rod if it is horizontal initially |
11 |
| 712 | The angle between force of friction and instantaneous velocity of the body moving over a rough surface is A. zero в. ( pi / 2 ) ( c . pi ) D. Insufficient data |
11 |
| 713 | A block of mass ( mathrm{m} ) is placed on a rough horizontal surface. The coefficient of friction between them is ( mu . ) An external horizontal force is applied to the block and its magnitude is gradually increased. The force exerted by the block on the surface is ( mathrm{R} ) then : This question has multiple correct options A. the magnitude of R will gradually increase B . ( R leq m g sqrt{mu^{2}+1} ) c. the angle made by R with the vertical will gradually increase. D. the angle made by R with the vertical ( leq tan ^{-1} mu ) |
11 |
| 714 | The propulsion of rocket illustrates that This question has multiple correct options A. Linear momentum is conserved B. Angular momentum is not conserved C. Newton’s third law is applicable D. Linear momentum is not conserved |
11 |
| 715 | In general, the relation between limiting friction rolling friction. |
11 |
| 716 | Two fixed frictionless inclined plane making an angle ( 30^{circ} ) and ( 60^{circ} ) with the vertical are shown in the figure. Two blocks ( A ) and ( B ) are placed on the two planes. What is the relative vertical acceleration of A with respect to B? |
11 |
| 717 | Figure shows a wedge of mass ( 2 k g ) resting on a frictionless floor. A block of mass ( 1 mathrm{kg} ) is kept on the wedge and the wedge is given an acceleration of 5 ( m / sec ^{2} ) towards right. Then: A. Block will remain stationary w.r.t. wedge B. The block will have an acceleration of ( 1 mathrm{m} / mathrm{sec}^{2} ) w.r.t. the wedge C. Normal reaction on the block is ( 11 N ) D. Net force acting on the wedge is ( 2 N ) |
11 |
| 718 | A light spring balance hangs from the hook of the other light spring balance and a block of mass ( M ) kg hangs from the former one. Then the true statement about scale reading is A. both the scales read ( M ) kg each B. the scale of the lower one reads ( M ) kg and of upper on zero c. the reading of the two scales can be anything but summ of the reading will be ( M ) kg D. both the scales read ( M / 2 mathrm{kg} ) |
11 |
| 719 | Calculate the force required to lift a load of ( 60 N, ) placed at a distance of ( 3 m, ) from the fulcrum if the effort force is applied at a distance of ( 6 mathrm{cm} ) from the fulcrum. ( A .300 N ) в. ( 3000 N ) c. ( 1500 N ) D. 30 ( N ) |
11 |
| 720 | The surface of the head of a match stick and sides of a match box are deliberately made rough to: A. increase friction B. decrease friction c. increase amount of heat D. decrease amount of heat |
11 |
| 721 | A particle of mass ( m ) moving with a velocity of ( (4 hat{i}-hat{j}) m / s ) strikes a fixed wall and finally moves with a velocity of ( (3 hat{i}+2 hat{j}) m / s . ) Find (a) the impulse received by the particle (b) the coefficient of restitution between them in the collision |
11 |
| 722 | A block of mass ( 10 k g ) is placed on rough inclined plane of variable angle ( theta ) and friction coefficient ( boldsymbol{mu}_{s}=boldsymbol{mu}_{boldsymbol{k}}=mathbf{3} / mathbf{4} ) When ( theta ) is ( 37^{circ} ) net reaction force applied by inclined is ( vec{N}_{1} ) and when ( theta=53^{circ} ) net reaction force applied by inclined is ( vec{N}_{2} ) find ( left|overrightarrow{boldsymbol{N}}_{1}right|-left|overrightarrow{boldsymbol{N}}_{2}right| ) |
11 |
| 723 | A uniform chain of mass ( M ) and Length ( boldsymbol{L} ) is held vertically in such a way that its lower end just touches the horizontal floor. The chain is released from rest in this position. Any portion that strikes the floor comes to rest. Assuming that the chain does not form a heap on the floor, calculate the force exerted by it on the floor, when a length ( x ) has reached the floor. |
11 |
| 724 | Two identical bullets are fired one by a light rifle and another by a heavy rifle with the same force. Which rifle will hurt the shoulder more and why? A. Light rifle B. Heavy rifle c. Both of them will hurt equally D. None of these |
11 |
| 725 | A ball of mass ( 2 k g ) is connected to a string of length ( 1 m ) and made to move in a horizontal circle on a smooth frictionless table with a constant speed of ( 2 m / s . ) The other end of the string is connected to a fixed peg on the table. Find the magnitude of the average impulse exerted by the string on the ball in half a revolution: A. 0 в. ( 8 N-s ) c. ( 4 N-s ) D. ( 2 sqrt{2} N-s ) |
11 |
| 726 | Assertion A spaceship while entering the earth’s atmosphere is likely to catch fire. Reason The temperature of upper atmosphere is very high. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
11 |
| 727 | A high pressure tire rolls more easily than a low pressure tire because: A. Rolling resistance is less in high inflated tire B. Rolling resistance is more in high inflated tire c. Rolling resistance is zero in high pressure tire D. Friction is zero in high pressure tire |
11 |
| 728 | Fluid friction is exerted by A. solids and liquids B. solids and gases c. liquids and gases D. all the above |
11 |
| 729 | A particle of small mass ( m ) is joined to a very heavy body of mass ( M ) by a light string passing over a light pulley. Both bodies are free to move. The total downward force on the pulley is nearly A . ( m g ) в. ( 2 m g ) c. ( 4 m g ) D. Can not be determined |
11 |
| 730 | 100. A block of mass 5.0 kg slides down from the top of an inclined plane of length 3 m. The first 1 m of the plane is smooth and the next 2 m is rough. The block is released from rest and again comes to rest at the bottom of the plane. If the plane is inclined at 30° with the horizontal, find the coefficient of friction on the rough portion. Smooth 1 m 2 m Rough R Fig. 8.272 |
11 |
| 731 | na 57. Figure 6.338 shows the variation of force act body with time. Assuming the body to start from rest, the variation of its momentum with time is best represented by which plot? F(N) 1 201– Fig. 6.338 P(kg m s-‘) b. P(kg m s’) t (s) (8) 4 P(kg m s-) P(kg m s-) t(s) |
11 |
| 732 | When a bus starts suddenly, the passengers are pushed backwards. Which of the following laws is illustrated in this example? A. Newton’s first law B. Newton’s second law c. Newton’s third law D. None of Newton’s laws |
11 |
| 733 | A car starts from rest to cover distance ( s . ) The coefficient of kinetic friction between the road and tire is ( mu ). The minimum time in which the car cover the distance ( s ) is proportional to ( A cdot mu ) B. ( sqrt{mu} ) ( c cdot frac{1}{mu} ) D. ( frac{1}{sqrt{mu}} ) |
11 |
| 734 | Two blocks of masses ( 2 mathrm{kg} ) and ( 1 mathrm{kg} ) are placed on a smooth horizontal table i contact with each other.A horizontal force of 3 newton is applied on the first so that the block moves with a constant acceleration. The force between the blocks would be:- ( A cdot 3 N ) B. 2 N c. ( 1 mathrm{N} ) D. ZERO |
11 |
| 735 | Action and reaction A. always act on two different bodies B. are equal in magnitude C . act in opposite directions D. All the above |
11 |
| 736 | Assertion A cloth covers a table. Some dishes are kept on it. The cloth can be pulled out without dislodging the dishes from the table. Reason For every action there is an equal and opposite reaction. A. Statement- – – is True, Statement-2 is True; Statement is a correct explanation for Statement- B. Statement-1 is True, Statement-2 is True; Statement- is NOT a correct explanation for Statement-1 c. Statement- – 1 is True, Statement- 2 is False D. Statement- -1 is False, Statement-2 is True |
11 |
| 737 | In the arrangement shown in figure the mass ( M ) is very heavy compared to ( boldsymbol{m}(boldsymbol{M}>+>boldsymbol{m}) . ) The tension ( boldsymbol{T} ) in the string suspended from the ceiling is A. ( 4 m g ) в. ( 2 m g ) c. zero D. None of the above |
11 |
| 738 | If a body of mass ( 5 g ) initially at rest is acted upon by a force of 50 dynes for ( 3 s ) Then the impulse will be A ( cdot 0.98 times 10^{-3} N s ) В. ( 1.5 times 10^{-3} N s ) c. ( 2.0 times 10^{-3} N s ) D. 2.5 ( times 10^{-3} mathrm{Ns} ) |
11 |
| 739 | 45. Find the net tension force acting on the lower support. a. Mg b. 2M2 c. 3Mg d. 4Mg |
11 |
| 740 | Friction is much lesser in in sliding. |
11 |
| 741 | When a body is in translatory equilibrium A. the body is definitely at rest B. the body is definitely in the state of uniform motion C. the body will be either at rest or in the state of uniform motion D. none of these |
11 |
| 742 | 3. A block A of mass m is placed over a plank B of mass 2 m. Plank B is placed over a smooth horizontal surface. The coefficient of friction between A and B is 0.4. Block | B A is given a velocity vo towards right. Fig. 7.354 Find acceleration (in ms) of B relative to A. |
11 |
| 743 | If the surface shown in fig is frictionless, the ratio of ( T_{1} ) and ( T_{2} ) is: A . 10: 1 B . 4: 1 ( c .5: 4 ) D. 5: 1 |
11 |
| 744 | m um 10. A system is pushed by a force F as shown in Fig. 7.266. All surfaces are smooth except between B and C. Friction F ► 2m coefficient between B and C is u. Minimum value of F to Fig. 7.266 prevent block B from down ward slipping is 3 1 mg 2u (20) c. umg umg umg |
11 |
| 745 | 41. An ideal liquid of density p is pushed with velocity v through the central limb of the tube shown in Fig. 6.324. What force does the liquid exert on the tube? The cross sectional areas of the three limbs are equal to A each. Assume stream-line flow. 60° 60° 60° 60° Fig. 6.324 a. Par? b. Par? a. ? / P Av² d. par? |
11 |
| 746 | In the given figure a monkey of mass ( m ) is climbing a rope hanging from the roof with acceleration a. the coefficient of static friction between the body of the monkey and the rope is ( mu ) find the direction and value of friction on the monkey. |
11 |
| 747 | Assertion (A) : A wheel may be rotated with uniform angular velocity even though the tangential forces are applied on it. Reason (R) : Angular acceleration of wheel is zero when tangential force and frictional force produce torques equal in magnitude and opposite in direction A. Both A and R are true and R is correct explanation of A B. Both A and R are true and R is not correct explanation of A C. A is true and R is false D. A is false and R is true |
11 |
| 748 | A car and a lorry are travelling with same velocity on a straight horizontal road. Which of the two has got greater momentum? |
11 |
| 749 | A body of mass ( 3 k g ) hits a wall at an angle of ( 60^{circ} ) and returns at the same angle. The impact time was 0.2 sec. The fores exerted on the wall B. ( 50 sqrt{3} N ) c. ( 100 N ) D. ( 75 sqrt{3} N ) |
11 |
| 750 | A ball moving with a speed ( v ) hits a massive wall and returns with speed ( v ) The impact lasts for time ( Delta t, ) then which of the following are correct: This question has multiple correct options A . average force acting on the ball is ( frac{2 m v}{Delta t} ) B. average force acting on the ball is ( frac{m v}{Delta t} ) c. kinetic energy of the ball becomes twice D. kinetic energy of the ball remains the same |
11 |
| 751 | Assertion When a person walks on a rough surface, the frictional force exerted by surface on the person is opposite to the direction of his motion. Reason It is the force exerted by the road on the person that causes the motion. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
11 |
| 752 | Two forces act on either side of rigid body of negligible mass suspended by string as shown in the figure. If ( mathrm{R} ) is the resultant force the tension of the string ( T=—– ) gwt ( A cdot 26 ) B. 41 c. 82 D. 16 |
11 |
| 753 | In shown diagram, tension in the cord is A. Zero B. 25 N ( c cdot 50 N ) D. ( 100 mathrm{N} ) E. 200 N |
11 |
| 754 | Three monkeys ( A, B ) and ( C ) with masses of ( 10,15 & 8 k g ) respectively are climbing up ( & ) down the rope suspended from ( D ). At the instant represented, ( A ) is descending the rope with an acceleration of ( 2 m / s^{2} & C ) is pulling himself up with acceleration of ( 1.5 m / s^{2} . ) Monkey ( B ) is climbing up with a constant speed of ( 0.8 m / s . ) Calculate the tension ( T ) in the rope at ( D .(g= ) ( left.10 m / s^{-2}right) ) |
11 |
| 755 | An instrument box placed on a table is given a push. It is observed that it stops its motion after some time. What is the force that stopped its motion? A . Gravitational force B. Tension force c. Friction force D. Mechanical force |
11 |
| 756 | A block of mass 2 kg slides down an incline plane of inclination ( 30^{0} . ) The coefficient of friction between block and plane is ( 0.5 . ) The contact force between block and plank is: A. 20 N B. ( 10 sqrt{3} ) N c. ( 5 sqrt{7} ) N D. ( 5 sqrt{15} ) N |
11 |
| 757 | DO UL. 4. With what force F a man pull on a rope in order to support the platform on which he stands, if the mass of man is 60 kg and that at platform is 20 kg. With what force N does the man press the platforms? What is the maximum weight of the platform that the man can support? Fig. 6.284 1 6 1 : limbing |
11 |
| 758 | Two balls of the same size but of different materials, rubber and iron are kept on the smooth floor of a moving train. The brakes are applied suddenly to stop the train. Will the balls start rolling? If so, in which direction? Will they move with the same speed? A. Iron ball is faster than rubber ball B. Rubber ball is faster than iron bal c. Both move at the same speed D. None of them move |
11 |
| 759 | The mass of an object is a measure of inertia: A. quantitative B. qualitative c. absolute D. average |
11 |
| 760 | 67. In Fig. 6.347, the acceleration of A is aa = 15i +15). Then the acceleration of B is (A remains in contact with B) 37° B Fig. 6.347 î b. – 15i c. – 101 d. –si a. 6 1 . petitely |
11 |
| 761 | Show that rate of change of momentum = mass ltimes acceleration.Under what condition does this relation hold |
11 |
| 762 | Who among the following anticipated Newton by declaring that all things gravitate to the earth? A. Buddhagupta B. Varahamihira c. Aeyabhatta D. Brahmagupta |
11 |
| 763 | How much momentum will a dumb-bel of mass ( 10 mathrm{kg} ) transfer to the floor if it falls from a height of ( 80 mathrm{cm} ) ? Take its downward acceleration to be ( 10 mathrm{m} mathrm{s}^{-2} ) |
11 |
| 764 | ( fleft(mu_{s}, mu_{k}, mu_{r} ) are coefficients of static right. friction, sliding friction and rolling friction then A ( cdot mu_{s}<mu_{k}<mu_{r} ) B . ( mu_{k}<mu_{r}<mu_{s} ) c. ( mu_{r}<mu_{k}<mu_{s} ) D. ( mu_{r}=mu_{k}=mu_{s} ) |
11 |
| 765 | 1. In the situation shown in Fig. 8.297 all contact surfaces are smooth. The force constant of the spring is K. Two forces F are applied as shown. The maximum elongation produced in the spring is how many times of F/K (initially the spring is relaxed)? Femmmm MF Fig. 8.297 |
11 |
| 766 | Two uniform boards, tied together with the help of a string, are balanced on a surface as shown in Fig. The coefficient of static friction between boards and surface is ( 0.5 . ) The minimum value of ( theta ) for which this type of arrangement is possible is : ( mathbf{A} cdot 30^{circ} ) B . ( 45^{circ} ) ( c cdot 37^{circ} ) D. It is not possible to have this type of balanced arrangementt |
11 |
| 767 | MULP PE 1. A reference frame attached to the Earth a. is an inertial frame by definition. b. cannot be an inertial frame because the Earth is revolving round the Sun. c. is an inertial frame because Newton’s laws are applicable in this frame. d. cannot be an inertial frame because the Earth is rotating abut its own axis. (IIT JEE, 1986) |
11 |
| 768 | If there are many forces acting on an object, it must have a non-zero net (unbalanced) force acting on it. A. True B. False |
11 |
| 769 | The force required to just move a body up the inclined plane is double the force required to just prevent the body from sliding down the plane. The coefficient of friction is ( mu . ) If ( theta ) is the angle of inclination of the plane, then ( tan theta ) is equal to ( mathbf{A} cdot mathbf{mu} ) в. ( 3 mu ) ( c cdot 2 mu ) D. ( 0.5 mu ) |
11 |
| 770 | Pulun. 4. The elevator shown in Fig. 6.394 is descending with an acceleration of 2 ms. The mass of the block A = 0.5 kg. Find the force (in Newton) exerted by block A on block B. 2 ms-2 Fig. 6.394 irononcceleration 12m-2 towards left a Del A |
11 |
| 771 | A filled shopping cart (30.0kg) is being pushed rapidly toward the back of a store so that its velocity is ( 2.0 mathrm{m} / mathrm{s} ) What is the momentum of the cart. and what is the kinetic energy of the cart? A. ( 90 k g m / s ) and ( 60 J ) B. ( 60 k g m / s ) and ( 90 J ) c. ( 60 k g m / s ) and ( 60 J ) D. ( 90 k g m / s ) and ( 90 J ) |
11 |
| 772 | Why are ball bearings used in machinery? | 11 |
| 773 | toppr Q Type your question around the spool through which a mass ( mathrm{m} ) is hanging. There exists no friction at point ( A, ) while the coefficient of friction between spool and point ( B ) is ( mu . ) The angle between two surfaces is ( theta ) This question has multiple correct options A. the magnitude of force on the spool at B in order to maintain equilibrium is ( m g sqrt{left(frac{r}{R}right)^{2}+left(1-frac{r}{R}right)^{2}} frac{1}{tan ^{2} theta} ) B. the magnitude of force on the spool at ( B ) in order to maintain equilibrium is ( m gleft(1-frac{r}{R}right) frac{1}{tan theta} ) C. the maintain value of ( mu ) for the system to remain in equilibrium is ( frac{cot theta}{(R / r)-1} ) D. the maintain value of ( mu ) for the system to remain in equilibrium is ( frac{tan theta}{(R / r)-1} ) |
11 |
| 774 | 12. Acceleration of Block B is a. 20 ms? b. 5 ms2 c. 15 ms-2 d. 10 ms-2 f or Ain bericento di |
11 |
| 775 | To reduce the momentum of a given body to half its original value then the velocity must be A. reduced to half B. reduced to one-third c. doubled D. remain same |
11 |
| 776 | Which will have least inertia? ( A ). A football B. A needle C. A thread D. A refrigerator |
11 |
| 777 | The action and reaction force referred to in the third law A. must act on the same object B. must act on different object c. may act on different object D. act in the same direction |
11 |
| 778 | A body acted upon by three forces ( vec{F}_{1}, vec{F}_{2} ) and ( vec{F}_{3} ) is under equilibrium. Given ( left|vec{F}_{1}right|=10 N,left|vec{F}_{2}right|=6 N ) This question has multiple correct options ( A cdot F_{3}=8 N ) В ( cdot F_{3}=6 N ) ( mathbf{c} cdot theta=53 ) |
11 |
| 779 | According to the diagram shown, identify the normal force : lined plan ( A cdot f ) ( mathbf{B} cdot F ) c. It may be ( f ) or ( F ) D. None of the above |
11 |
| 780 | A machine gun of mass ( 12 mathrm{kg} ) fires ( 25 mathrm{g} ) bullets at the rate of 4 bullets per second with a velocity of ( 500 mathrm{m} s^{-1} ) What force must be applied to the gun to hold it in position? A. 20 N B. 12.5 N c. ( 50 mathrm{N} ) D. 75 N |
11 |
| 781 | 36. A 60-kg man stands on a spring scale in a lift. At some instant, he finds that the scale reading has changed from 60 kg to 50 kg for a while and then comes back to original mark. What should be concluded? a. The lift was in constant motion upward. b. The lift was in constant motion downward. c. The lift while in motion downward suddenly stopped. d. The lift while in motion upward suddenly stopped. |
11 |
| 782 | A body is sliding down an inclined plane having coefficient of friction ( 0.5 . ) If the normal reaction is twice that of the resultant downward force along the incline, the angle between the inclined plane and horizontal is A ( cdot 15^{circ} ) B . ( 30^{circ} ) ( c cdot 45^{circ} ) D. ( 60^{circ} ) |
11 |
| 783 | Neglect friction. Find accelerations of ( m, 2 m ) and ( 3 m ) as shown in the figure. The wedge (inclination ( =30^{circ} ) ) is fixed |
11 |
| 784 | A small disk being pulled by a constant horizontal force ( F ) on an inclined plane moves with a constant velocity v as shown in the figure. The angle of inclination of the plane from the horizontal is ( alpha ) and angle between the velocity vector and the force vector is ( beta ) Find the coefficient of kinetic friction between the disk and the plane. |
11 |
| 785 | Limiting friction is A. Directly proportional to the area of contact B. Inversely proportional to the area of contact C. Independent on the area ofcontact D. All of these |
11 |
| 786 | Akhtar, Kiran and Rahul were riding in a motorcar that was moving with a high velocity on an expressway when an insect hit the windshield and got stuck on the windscreen. Akhtar and Kiran started pondering over the situation. Kiran suggested that the insect suffered a greater change in momentum as compared to the change in momentum of the motorcar(because the change in the velocity of the insect was much more than that of the motorcar). Akhtar said that since the motorcar was moving with a larger velocity, it exerted a larger force on the insect. And as a result the insect died. Rahul while putting an entirely new explanation said that both the motorcar and the insect experienced the same force and a change in their momentum. Comment on these suggestions. |
11 |
| 787 | The behavior of a body under zero resultant force is given by: A. Newtons third law of motion B. Newtons second law of motion c. Newtons first law of motion D. Newtons law of gravitation |
11 |
| 788 | The engine of a car produces an acceleration of ( 6 m / s^{2} ) in the car. If this car pulls a block of the same mass, then the acceleration would be: ( mathbf{A} cdot 6 m / s^{2} ) B . ( 12 mathrm{m} / mathrm{s}^{2} ) c. ( 3 m / s^{2} ) D. ( 1.5 mathrm{m} / mathrm{s}^{2} ) |
11 |
| 789 | Given figure shows a shovel used to lift earth (sand). A and B are hinges connecting the shovel to the two rods shown. The weight of the shovel and sand is ( 12 k N ) acting at G. The magnitude of the force ( F ) is ( 5 k N ). The reactive force at B is : (All dimension in ( c m ) ) A ( .0 k N ) B. ( 9.8 k N ) ( begin{array}{ll}.17 .66 k N & Nend{array} ) D. ( 20 k N ) |
11 |
| 790 | A ball of mass ( 0.1 mathrm{kg} ) strikes a wall normally with a speed of ( 30 m s^{-1} ) and rebounds with a speed of ( 20 m s^{-1} . ) The impulse of the force exerted by the wall on the ball is A. ( 1 N s ) в. 5 Ns ( c .2 N s ) D. 3 Ns |
11 |
| 791 | A block of mass ( 3 k g ) which is on a smooth inclined plane making an angle of ( 30^{circ} ) to the horizontal is connected by second block of mass ( 2 k g ) hanging vertically, What is the acceleration of each block and what is the tension of the cord? A ( cdot 0.98 m / s^{2} ; 17.6 N ) B . ( 1.98 m / s^{2} ; 19.6 N ) c. ( 0.49 m / s^{2} ; 9.8 N ) D. ( 1.47 m / s^{2} ; 4.9 N ) |
11 |
| 792 | Find the time period of disc? | 11 |
| 793 | Three forces ( A, B ) and ( C ) acting at a point are in equilibrium. The ratio of angles between ( A ) and ( B ; B ) and ( C ; ) and ( A ) and ( C ) is ( 1: 2: 3 . ) Then, ( A: B: C ) is A. ( 1: frac{sqrt{3}}{2}: frac{1}{2} ) B. ( frac{1}{2}: frac{sqrt{3}}{2}: 1 ) c. ( _{1: frac{1}{2}: frac{1}{3}} ) D. ( 1: frac{1}{sqrt{2}}: frac{1}{sqrt{3}} ) E. None of these |
11 |
| 794 | UUU IN 8. Average force exerted by the bat on the ball is a. 5000 N b. 2000 N c. 2500 N d. 6000 N T h eodof the ball at the inatone 41. |
11 |
| 795 | The friction between two bodies produces A. Motion B. Expansion c. Heat D. None |
11 |
| 796 | Two weight ( w_{1} ) and ( w_{2} ) are connected by a light thread which passes over a light smooth pulley. If the pulley is raised upward with an acceleration equal to ( g ) then tension in the thread will be A ( cdot frac{2 w_{1} w_{2}}{w_{1}+w_{2}} ) в. ( frac{w_{1} w_{2}}{w_{1}+w_{2}} ) c. ( frac{4 w_{1} w_{2}}{w_{1}+w_{2}} ) D. ( frac{4 w_{1} w_{2}}{w_{1}-w_{2}} ) |
11 |
| 797 | The earth pulls a stone downwards due to gravity. The stone exerts: A. an equal and opposite force on the earth B. a greater force on the earth c. a lesser force on the earth D. no force on the earth |
11 |
| 798 | What ways do you know to reduce friction? |
11 |
| 799 | A rod of weight ( boldsymbol{w} ) is supported by two parallel knife edges ( A & B ) and is in equilibrium in a horizontal position. The knives are at a distance ( d ) from each other. The center of mass of the rod is at a distance ( x ) from ( A ). The normal reactions at ( A ) and ( B ) will be A ( . N_{A}=2 w(1-x / d), N_{B}=w x / d ) B . ( N_{A}=w(1-x / d), N_{B}=w x / d ) c. ( N_{A}=2 w(1-x / d), N_{B}=2 w x / d ) D. ( N_{A}=w(2-x / d), N_{B}=w x / d ) |
11 |
| 800 | 11. In Fig. 6.365, the blocks A, B, and C of mass meach acceleration a, a, and az, respectively. F, and p external forces of magnitude 2mg and mg, respecti Then F-2 mg F2 = mg Fig. 6.365 a. a, & at az c. a, > a, > az b. a, = az az d. a, # ay = az |
11 |
| 801 | 18. The speed of the bob at the lowest point is a. 9.2 ms b. 9 ms-1 c. 6.5 ms’ d. 8 ms |
11 |
| 802 | Classify the following as motion along a straight line, circular or oscillatory motion. (i) Motion of your hands while running. (ii) Motion of a horse pulling a cart on a straight road. (iii) Motion of a child in a merry-goround. (iv) Motion of a child on a see-saw. (v) Motion of a hammer of an electric bell. (vi) Motion of a train on a straight bridge. |
11 |
| 803 | Which of the following are done to increase friction? A. Greasing the machines B. Treanding the tyres c. sprinkling powder on the carom board D. All of the above |
11 |
| 804 | A block of mass ( m ) slides down an inclined plane of slope angle ( theta ) with constant velocity. Now, same block is projected up an inclined plane with an initial velocity ( u ). If the coefficient of kinetic friction between the block and the plane is ( mu, ) the distance up to which the block will rise up the plane, before coming to rest is :- ( ^{mathrm{A}} cdot frac{u^{2} mu}{2 g sin theta} ) в. ( frac{u^{2} mu}{2 g cos theta} ) c. ( frac{u^{2}}{4 g sin theta} ) D. ( frac{u^{2}}{4 g cos theta} ) |
11 |
| 805 | A circular road of radius r is banked for a speed ( mathbf{v}=40 mathrm{km} / mathrm{hr} . ) A car of mass ( mathrm{m} ) attempts to go on the circular road. The friction coefficient between the tyre and the road is negligible. A. The car cannot make a turn without skidding B. if the car turns at a speed less than ( 40 mathrm{km} / mathrm{hr} ), it will slip down. C. If the car turns at the correct speed of ( 40 mathrm{km} / mathrm{hr} ), the force by the road on the car is equal to ( m v^{2} / r ) D. If the car turns at the correct speed of ( 40 mathrm{km} / mathrm{hr} ), the force by the road on the car is greater than mg as well as greater than ( m v^{2} / r ) |
11 |
| 806 | Every body continues to be in its state of rest or of non-uniform motion in a straight line unless compelled by some external force to act otherwise. This is stated by: A. Newton’s 1st law B. Newton’s 2nd law c. Newton’s 3rd law D. None of the above |
11 |
| 807 | A car moves at a speed of ( 20 mathrm{ms}^{-1} ) on a banked track and describes an arc of a circle of radius ( 40 sqrt{3} . ) The angle of banking is (take, ( left.g=10 m s^{-2}right) ) A ( .25^{circ} ) B. 60 ( c cdot 45 ) D. 30 E ( .40^{circ} ) |
11 |
| 808 | A person, exerting a steady force of ( 200 N, ) pushes a box of mass ( 50 k g ) across a flat wooden floor. If the box does not move while he pushes. Find out the coefficient of kinetic friction between the box and the floor? A . 0.2 B. 0.4 c. 0.5 D. 0.6 E . 0.8 |
11 |
| 809 | A ladder of length I and mass m is placed against a smooth vertical wall, but the ground is not smooth. Coefficient of friction between the ground and the ladder is ( mu . ) The angle ( theta ) at which the ladder will stay in equilibrium is: A ( cdot theta=tan ^{-1}(mu) ) B . ( theta=tan ^{-1}(2 mu) ) c. ( theta=tan ^{-1}left(frac{mu}{2}right) ) D. none of these |
11 |
| 810 | A body is accelerated by applying a force of 30 N. The change in the momentum of the body after 2 sec is? A. ( 7.5 mathrm{kg}-mathrm{m} / mathrm{s} ) B. ( 30 mathrm{kg}-mathrm{m} / mathrm{s} ) c. ( 120 mathrm{kg}-mathrm{m} / mathrm{s} ) D. ( 60 mathrm{kg}-mathrm{m} / mathrm{s} ) |
11 |
| 811 | Frictional force is more between which type of surfaces? A. Smooth B. Rough c. Both A and B D. None of the above |
11 |
| 812 | 38. Find the duration for which the force acts on the body. a. 2s b. 3. c. 3.55 d. 4.55 |
11 |
| 813 | A block of wood mass ( 5 k g ) is placed on a plane making an angle ( 30^{circ} ) with the horizontal. If the coefficient of friction between the surface of contact of the body and the plane is ( 0.5 . ) What force is required to keep the body sliding down with uniform velocity? A. ( 1.6 N ) B. ( 4.8 N ) ( c cdot 6.4 N ) D. ( 3.35 N ) |
11 |
| 814 | connected by a string going over clamped light smooth pulley as shown in figure. The system is released from rest. The larger mass is stropped for a moment ( 1.0 s ) after the system is set in motion. Find the time elapsed before the string is tight again. ( mathbf{A} cdot frac{1}{3} s ) B . ( 1 s ) c. ( 2 s ) D. ( 3 s ) |
11 |
| 815 | A ( 1500 k g ) car moving on a flat road negotiates a curve whose radius is ( 35 m . ) If the coefficient of static friction between the tyres and the dry pavement is ( 0.5 . ) Find the maximum speed, the car can have in order to make the turn successfully. A. ( 13.1 mathrm{m} / mathrm{s} ) В. ( 15.1 mathrm{m} / mathrm{s} ) c. ( 20 m / s ) D. ( 25 mathrm{m} / mathrm{s} ) |
11 |
| 816 | Every action has its equal and opposite reaction is Newton’s: A. First law of motion B. Second law of motion c. Third law of motion D. Fourth law of motion |
11 |
| 817 | A ball is moving in the direction as shown. What will be the direction of momentum? ( A . W ) в. ( N ) ( c . s ) D. |
11 |
| 818 | If a machine is Iubricated with oil A. The mechanical advantage of the machine increases B. The mechanical efficiency of the machine increases C. Both its mechanical advantage and efficiency increase D. Its efficiency increases, but its mechanical advantage decreases |
11 |
| 819 | Two identical balls each of mass ( 4 mathrm{kg} ) are moving towards each other with speeds ( 2 mathrm{m} / mathrm{s} ) and ( 3 mathrm{m} / mathrm{s} ) respectively they undergo head on perfectly elastic collision. the impulse imparted by one ball on other is: A . ( 12 mathrm{Ns} ) B. 8 Ns c. ( 20 mathrm{Ns} ) D. ( 40 mathrm{Ns} ) |
11 |
| 820 | Physical independence of force is a consequence of A. Newton’s third law of motion B. Newton’s second law of motion c. Newton’s first law of motion D. All of these |
11 |
| 821 | Two forces which are perpendicular to each other, act on a body. The resultant force ( F_{1} ) makes an angle of ( 60^{circ} ) with one force. The magnitude of the other force is? A ( cdot sqrt{3} F / 2 ) B . ( F / sqrt{2} ) c. ( F / 2 ) D. ( 2 F ) |
11 |
| 822 | Newton’s second law gives a measure of A. Acceleration B. Force c. Momentum D. Angular momentum |
11 |
| 823 | 42. Let F, and F2 be applied in such a way that m, and my do not move w.r.t. M. Then what is the magnitude of the acceleration of M? Let m > m. (m + m₂)8 ( m m₂)8 M+m, + m2 M (m-m2)8 M + m + m2 a. b. d. Fi-F₂ M |
11 |
| 824 | The impulse of a body is equal to: A. Rate of change of its momentum. B. Change in its momentum. C. The product of force applied on it and the time of application of the force. D. Both (B) and (C) |
11 |
| 825 | Which of the following material is likely to have least friction? A. wood c. glass D. paper |
11 |
| 826 | If a car and a truck are moving with same momentum, the velocity of car is the velocity of truck. A. Greater than B. Lesser than c. Equal to D. might be lesser than |
11 |
| 827 | In the given situation it is known that when released the blocks slide. Find the time(in second) when the small block will fall off from the larger block. (The size of ( m ) is very -very small then ( M, ) see figure). If ( boldsymbol{m}=mathbf{1} mathbf{k g}, boldsymbol{M}=mathbf{4 k g}, boldsymbol{l}=mathbf{4 m} ) ( boldsymbol{theta}=mathbf{3 7}^{o}, boldsymbol{mu}=mathbf{0 . 4} ) |
11 |
| 828 | A monkey of mass ( m k g ) slides down a light rope attached to a fixed spring balance, with an acceleration ( a ). The reading of the spring balance is ( mathrm{W} ) kg. ( [mathrm{g} ) ( = ) acceleration due to gravity]. Then: This question has multiple correct options A. the force of friction exerted by the rope on the monkey is ( m(g-a) N ) в. ( m=frac{W g}{g-a} ) c. ( m=Wleft(1+frac{a}{g}right) ) D. the tension in the rope is ( W g N ) |
11 |
| 829 | 5. The ring shown in Fig. 6.360 is given a constant horizontal acceleration (a, = g/13). The maximum deflection of the string from the vertical is 6, then m Smooth horizontal rail I particle Fig. 6.360 a. 0 = 30° b. 0 = 60° c. At maximum deflection, tension in string is equal to mg. d. At maximum deflection, tension in string is equal to 2mg |
11 |
| 830 | Jahnvi is walking at ( 1.63 m / s ). If she weighs ( 583 N, ) what is the magnitude of her momentum? A. ( 951 mathrm{kg} mathrm{m} / mathrm{s} 951 mathrm{kg} mathrm{m} / mathrm{s} ) в. ( 68.8 mathrm{kg} mathrm{m} / mathrm{s} ) c. 137 kg ( m / s ) D. 672 kg ( m / s ) |
11 |
| 831 | The figure shows the position time ( (x- ) t) graph of one-dimensional motion of a body of mass 0.4 kg. The magnitude of each impulse is A. ( 0.4 mathrm{Ns} ) B. 0.8 Ns c. ( 1.6 mathrm{Ns} ) D. ( 0.2 mathrm{Ns} ) |
11 |
| 832 | Calculate N and a | 11 |
| 833 | U. TUNC OI mese 57. A block of mass m is attached with a massless spring of force constant k. The block is placed over a fixed rough inclined surface for which the coefficient of friction is u= The block of mass m is initially at rest. The block of mass M is released from rest with spring in upstretched state. The minimum value of M required to move the block up the plane is (neglect mass of string and pulley and friction in pulley.) 4 m M 370 |
11 |
| 834 | A body rests on a rough horizontal plane. A force is applied to the body directed towards the plane at an angle ( alpha ) with the vertical. The body can be moved along the plane A. only if ( alpha ) is greater than the angle of friction B. only if ( alpha ) is lesser than the angle of friction c. only if ( alpha ) is equal to the angle of friction D. for all values of ( alpha ) |
11 |
| 835 | A ball of mass ( =100 g m ) is released from a height ( h_{1}=2.5 m ) above the ground level and then rebounds to a height ( h_{2}=0.625 m . ) The time of contact of the ball with the ground is ( Delta t=0.01 ) sec. Find the impulsive (impact) force offered by the ball on the ground. |
11 |
| 836 | 44. The extension produced in the spring is given by a. 4Mg/K b. Mg/K c. 2Mg/K d. 3Mg/K |
11 |
| 837 | A body projected from the bottom of a smooth inclined plane with a velocity ( 9.8 m / )sec. The angle of inclination of the plane is ( 30^{circ} . ) If it comes to rest after reaching the top of the plane, then the time of ascent is A. 2 sec B. 1 sec ( c .0 .5 mathrm{sec} ) D. 1.5 sec |
11 |
| 838 | A ( T ) shaped object with dimensions shown in fig, is lying on smooth floor. ( mathbf{A} ) force ( F ) is applied at point ( P ) parallel to AB such that the object has only translation motion without rotation. Find location of ( boldsymbol{P} ) from ( boldsymbol{C} ) A ( cdot frac{2}{3} l ) в. ( frac{3}{2} l ) ( c cdot frac{4}{3} l ) D. |
11 |
| 839 | An instantenous displacement of a simple harmonic oscillator is ( boldsymbol{x}= ) ( boldsymbol{A} cos left(boldsymbol{omega} boldsymbol{t}+frac{pi}{4}right) . ) Its speed will be maximum at time: A ( cdot frac{pi}{4 omega} ) в. ( frac{pi}{2 omega} ) c. ( frac{pi}{omega} ) D. ( frac{2 pi}{omega} ) |
11 |
| 840 | Newton’s law of motion were stated by the scientist named as Charles- Augustin A. True B. False |
11 |
| 841 | Fluid friction depends on A. speed of the object B. shape of the object c. nature of fluid D. all of the above |
11 |
| 842 | State and explain the law of inertia (or Newton’s first law of motion). | 11 |
| 843 | It is found that a body on an inclined plane just starts sliding down if inclination is ( sin ^{-1}(3 / 5), ) then the angle of repose (friction) is This question has multiple correct options A ( cdot sin ^{-1} 3 / 5 ) B ( cdot sin ^{-1} 3 / 4 ) c. ( tan ^{-1} 3 / 5 ) ( mathbf{D} cdot tan ^{-1} 3 / 4 ) |
11 |
| 844 | A uniform rod ( A B ) of mass ( 2 k g ) is hinged at one end ( A ). The rod is kept in the horizontal position by a massless string tied to point ( B ). Find the reaction of the hinge ( (text { in } N) ) on end ( A ) of the rod at the instant when string is cut. ( left(g=10 m / s^{2}right) ) ( A cdot 6 ) в. 40 ( c cdot 15 ) D. |
11 |
| 845 | Four forces are acting on a body. if the body doesn’t change its position or shape, the forces: A. must be of equal magnitude B. must be parallel & opposite c. must add up to zero when taken as vectors D. must be in a single line |
11 |
| 846 | State whether true or false. Self balancing toys have curved and heavy bases. A. True B. False |
11 |
| 847 | A ( 1 mathrm{kg} ) block is attached by light string to another block of mass 2 kg. The string is passed over a pulley of negligible mass and friction. Calculate the acceleration of the masses? ( A cdot 5 m / s^{2} ) B. ( 6.7 m / s^{2} ) ( mathbf{c} cdot 10 m / s^{2} ) D. ( 20 m / s^{2} ) E. ( 30 m / s^{2} ) |
11 |
| 848 | Driving a car on a highway with windows open reduce the speed. This is due to: A. air resistance B. mechanical defect c. bad driving D. none of these |
11 |
| 849 | A bullet of mass ( 50 g ) travelling at ( 500 m / s ) penetrates ( 100 mathrm{cm} ) into a wooden block. Find the average force exerted on the block. B . ( 62.5 times 10^{4} N ) c. ( 6.25 times 10^{4} N ) D. ( 2.65 times 10^{4} N ) |
11 |
| 850 | An unbanked curve has a radius of ( 60 m ) Coefficient of friction between the tyre of truck and road is ( 0.75 . ) The distance between two front wheel of truck is ( 2 m ) If the truck exceeds the speed of safe limit, then select the correct statement and justify your asnwer. 1) Inner wheels leave the ground first. 2) Outer wheels leave the ground first. |
11 |
| 851 | If we drop a cup of water on a plate and a cup of oil on another plate, water is seen to spread faster along diameter. This is an example related to: A. fluid friction B. rolling friction c. sliding friction D. static friction |
11 |
| 852 | A box weighing ( 2000 N ) is to be slowly slid through ( 20 m ) on a straight track having friction coefficient 0.2 with the box. Find the work done by the person pulling the box with a chain at an angle ( theta ) with the horizontal. |
11 |
| 853 | A uniform ladder of length ( 5 m ) is placed against the wall as shown in the figure. If coefficient of friction ( mu ) is the same for both the walls, what is the minimum value of ( mu ) for it not to slip? A ( cdot mu=frac{1}{2} ) B. ( mu=frac{1}{4} ) ( c cdot_{mu}=frac{1}{3} ) D. ( mu=frac{1}{5} ) |
11 |
| 854 | If angle of repose is ( 30^{circ}, ) then coefficient of friction will be ( mathbf{A} cdot mathbf{1} ) B . 15 c. ( frac{1}{sqrt{3}} ) D. ( frac{sqrt{3}}{2} ) |
11 |
| 855 | E * 5P 29. In the following arrangement, the system is initially at rest. The 5-kg block is now released. Assuming the pulleys and string to be massless and smooth, the acceleration of block C will be 5kg Al 10 kg Bc 8 kg a. Zero c. 10/7 ms- Fig. 6.314 b. 2.5 ms-2 d. 5/7 ms-2 A . |
11 |
| 856 | Assertion On a rainy day, it is difficult to drive a car or bus at high speed. Reason The value of coefficient of friction is lowered due to wetting of the surface. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct. |
11 |
| 857 | A body slides down a rough inclined plane of inclination ( theta ) with constant velocity ( v ). If it is projected up the plane with velocity ( 2 v, ) then it moves up the plane with A. constant velocity B. retardation g ( sin theta ) c. retardation ( 2 mathrm{g} sin theta ) D. acceleration g sin ( theta ) |
11 |
| 858 | The force of gravity with which a body is attracted towards the centre of the earth is A. weight B. mass c. position D. ripple |
11 |
| 859 | To sharpen the blade of a knife by rubbing it against a surface, which of the following will be most suitable? A. stone B. plastic block C. wooden block D. glass block |
11 |
| 860 | If the beads are released from rest, such that the bead ( A ) is at the highest position of ring at time ( t=0, ) the magnitude of acceleration of the bead ( B ) in the vertical direction at the same instant is ( A ). Zero B. ( frac{g}{4} ) c. ( frac{g}{2} ) ( D ) |
11 |
| 861 | Two small balls ( A ) and ( B ) are made of same material. ( boldsymbol{A} ) is solid but ( boldsymbol{B} ) is hollow. These are connected by an ideal spring and this whole system is kept over a smooth plank such that center of mass of two balls coincide with mid point of the plank. Initially the spring is compressed by certain amount and the plank is in horizontal position. Now we release the system. Then: A. Plank will rotate clock wise B. Plank will rotate anti clock wise c. Plank will not rotate D. It will depend upon string constant |
11 |
| 862 | What are the differences between the mass of an object and its weight? |
11 |
| 863 | ilustration 7.18 A 5-kg block slides down a plane inclined at 30° to the horizontal. Find The acceleration of the block if the plane is frictionless. h The acceleration if the coefficient of kinetic friction is 1/2/3. |
11 |
| 864 | 3450 15. Two objects A and B, each of mass m, are connected by a light inextensible string. They are restricted to move on a frictionless ring of radius R in a vertical plane (as shown in Fig. 6.304). The objects are released from rest at the position shown. Then the tension Fig. 6.304 in the cord just after release is a. Zero b. mg c. V2 mg d. mg/12 |
11 |
| 865 | To keep machines running smoothly and to avoid wear and tear of machines, the best and the most commonly used lubricant is: A. Powder B. Sand ( c cdot ) oil D. water |
11 |
| 866 | A particle is projected up along a rough plane inclined at an angle of ( 45^{circ} ) with the horizontal, if the coefficient of friction is ( frac{1}{2}, ) then the retardation is: A ( cdot frac{g}{sqrt{2}} ) в. ( frac{g}{2} ) c. ( frac{g}{sqrt{2}}left(1+frac{1}{2}right) ) D. ( frac{g}{sqrt{2}}left(1-frac{1}{2}right) ) |
11 |
| 867 | A stationary ball weighing ( 0.25 k g ) acquires a speed of ( 10 m / s ) when hit by a hockey stick. The impulse imparted to the ball is ( mathbf{A} cdot 2.5 N s ) B. ( 2.0 N s ) c. ( 1.5 N s ) D. ( 0.5 N s ) |
11 |
| 868 | ( A ) and ( B ) are two objects with mass 6 kg and 34 kg respectively. Then, A. A has more inertia than ( B ) B. B has more inertia than A c. A and B both have same inertia D. None of the above statements is true |
11 |
| 869 | Consider a cylinder of mass ( M ) resting on a rough horizontal rug that is pulled out from under it with acceleration ( a ) perpendicular to the axis of the cylinder. What is ( F_{f r i c t i o n} ) at point ( P ? ) It is assumed that the cylinder does not slip. ( A cdot frac{M a}{3} ) в. ( M g ) ( c cdot frac{M a}{2} ) D. ( M a ) |
11 |
| 870 | A block is pushed with some velocity up a rough inclined plane. It stops after ascending few meters and then reverses its direction and returns back to point from where it started. If angle of inclination is ( 37^{circ} ) and the time to climb up is half of the time to return back then coefficient of friction is: ( mathbf{A} cdot frac{9}{20} ) B. ( frac{7}{5} ) c. ( frac{7}{12} ) D. ( frac{5}{7} ) |
11 |
| 871 | A girl is pushing on a crate with a force as great as the force of friction between the crate and the floor (see figure) Which one of the following is correct? A. The net force on the crate is zero B. The crate may be at rest or just start sliding c. The crate must not be accelerating D. All of the above |
11 |
| 872 | 28. Find the absolute acceleration of block 3. a. 2 ms upwards b. 1 ms – downwards c. 3 ms – downwards d. 1.5 ms upwards |
11 |
| 873 | When a body is placed on a surface, the body exerts a force in direction on the surface. Fill in the blank A. Downwards B. Upwards c. Both A and B D. None |
11 |
| 874 | A body of mass 5 kg has momentum of ( 10 mathrm{kg} mathrm{m} / mathrm{sec} . ) When a force of ( 0.2 mathrm{N} ) is applied on it for 10 sec, the change in its kinetic energy is: A . 4.4 в. 3.3 c. 5.5 D . 1.1 J |
11 |
| 875 | If a car is moving at a velocity ( v ) in a circular road with coefficient of friction ( mu ) and banking angle ( theta ). Find the radius of the road such that friction force doesn’t act on the car in the radial direction. A ( cdot_{r}=frac{v^{2}}{g tan theta} ) в. ( quad r=frac{sqrt{v}}{g tan theta} ) ( ^{mathrm{c}} cdot_{r}=sqrt{frac{v^{2}}{g tan theta}} ) D. ( r=frac{v^{2}}{sqrt{g}} ) |
11 |
| 876 | A force of ( 20 mathrm{N} ) acts on the ball for short duration. If ball of mass ( 0.5 mathrm{kg} ) acquire a speed of ( 4 mathrm{m} / mathrm{s} ) from the rest. For how long did this force act on the ball? A . ( 0.01 mathrm{s} ) B. 0.02 ( c cdot 0.1 mathrm{s} ) D. 0.2 E. ( 1 mathrm{s} ) |
11 |
| 877 | The depressions and elevations present on the surface of objects causes friction. A. True B. False c. Ambiguous D. Data insufficient |
11 |
| 878 | A cyclist leans with the horizontal at an angle of ( 30^{circ}, ) while negotiating round a circular road of radius ( 20 sqrt{3} ) meters. Speed of the cycle should be: A. ( 7 sqrt{3} mathrm{m} / mathrm{s} ) в. ( 14 mathrm{m} / mathrm{s} ) ( mathbf{c} cdot 7 sqrt{6} m / s ) D. ( 14 sqrt{3} mathrm{m} / mathrm{s} ) |
11 |
| 879 | A body of mass ( mathrm{M} ) is resting on a rough horizontal plane surface, the coefficient of friction being equal to ( mu . A t t=0, a ) horizontal force ( boldsymbol{F}=boldsymbol{F}_{0} boldsymbol{t} ) starts acting on it, where ( F_{0} ) is a constant. Find the time ( T ) at which the motion starts? A. ( mu M g / F_{0} ) ( mathbf{B} cdot M g / mu F_{0} ) ( mathbf{c} cdot mu F_{0} / M g ) D. None of these |
11 |
| 880 | A body rests on a rough horizontal plane. A force is applied to the body directed towards the plane at an angle ( emptyset ) with the vertical. The body can be moved along the plane A. Only ( emptyset ) is more than the angle of friction B. Only ( emptyset ) is less than the angle of friction c. only ( emptyset ) is equal to the angle of friction D. For all values of |
11 |
| 881 | If the angle of banking of a road is ( 32^{circ} ) and if a turn has radius ( 72 m, ) what is the maximum speed at which a car can turn, given the coefficient of friction between the car tyres and the road is ( mathbf{0 . 3 4} ?(operatorname{in} mathbf{m} / mathbf{s}) ) A . 29.4 B. 26.3 c. 21.3 D. 62.3 |
11 |
| 882 | State whether given statement is True or False. A five rupees coin has more inertia than a one-rupee coin. A. True B. False |
11 |
| 883 | It is advised to tie any luggage kept on the roof of a bus with a rope because of : A. Newtons first law B. Newtons second law c. Newtons third law D. None of these |
11 |
| 884 | A block of mass ‘ ( m^{prime} ) is placed on floor of a lift which is rough. The coefficient of friction between the block and the floor is ( mu . ) When the lift falls freely, the block is pulled horizontally on the lift floor. The force of friction is: A . zero в. ( 2 mu m g ) c. ( frac{1}{2} mu m g ) D. ( mu m g ) |
11 |
| 885 | A ball of mass M thrown upward if the air resistance is considered constant (R) What will be times of Ascent and decent. Give Mathematical proof. |
11 |
| 886 | Which of the following laws of motion is (are) involved in the motion of the rocket? A. Newton’s first law of motion. B. Newton’s second law of motion c. Newton’s third law of motion D. All the above |
11 |
| 887 | A force of 100 dynes acts on mass of 5 ( mathrm{gm} ) for 10 sec. The velocity produced is: A. ( 2 mathrm{cm} / mathrm{sec} ) B. 20 cm/sec c. ( 200 mathrm{cm} / mathrm{sec} ) D. 2000 cm/sec |
11 |
| 888 | Consider the situation shown in figure. Both the pulleys and the string are light and all the surfaces are frictionless. Calculate the force exerted by the clamp on the pulley A in the figure. |
11 |
| 889 | .JU . T.JS 39. Find the time when the velocity attained by the body is maximum. a. 2s b. 3s c. 3.5 s d. 4.5 s 40 Mark the correct statement. |
11 |
| 890 | A homogeneous chain of length ( L ) lies on a table. Some part of chain is hanging down the table. The coefficient of friction between the chain and the table is ( mu . ) The maximum length which can hangover the table in equilibrium is A ( cdot frac{mu L}{1+mu} ) в. ( left(frac{1-mu}{mu}right) L ) ( ^{C}left(frac{1-mu}{1+mu}right)^{2} ) D. ( left(frac{2 mu}{1+2 mu}right) ) |
11 |
| 891 | A force of ( 10 N ) acts on a body of mass ( 20 k g ) for ( 10 s . ) Change in its momentum is: ( mathbf{A} .5 k g m / s ) в. ( 100 k g m / s ) c. ( 200 k g m / s ) D. ( 1000 k g m / s ) |
11 |
| 892 | Name the property of matter due to which a body continues in its state of rest or uniform motion unless an external force acts on it is: A. Inertia B. Elasticity c. viscosity D. Density |
11 |
| 893 | Frictional force always opposes: A. The state of rest B. The state of motion c. None of the above D. Both the states |
11 |
| 894 | Which of the following safety features are used in vehicles to reduce the negative effects of inertia? (i)Safety seat belts (ii)Automatic air bags (iii)Absorber bumpers A. Only (i) and (ii) B. only (ii) and (iii) c. Only (i) and (iii) D. (i), (ii) and (iii) |
11 |
| 895 | A box is placed on an inclined plane and has to be pushed down. The angle of inclination will satisfy which options among the following: This question has multiple correct options A. Equal to angle of friction B. More than angle of friction c. Less than the angle of friction D. Greater than angle of repose |
11 |
| 896 | You are thrown ahead when your car suddenly comes to a halt and you are thrown backwards when your car rapidly accelerates. Which law of Newton is involved in this? A. Third law B. Second law c. First law D. Law of gravitation |
11 |
| 897 | 3. A block of mass 15 kg is resting on a rough inclined plane as shown in Fig. 7.261. The block is tied by a horizontal string which has a tension of 50 N. The coefficient of Z friction between the surfaces of contact 45 Fig. 7.261 a. 1/2 b. 213 c. 314 d. 1/4 |
11 |
| 898 | A block of weight 100 N lying in a horizontal surface just to move when a horizontal force of 25N acts on it. Determine the coefficient of static friction |
11 |
| 899 | What is the force on a body of mass ( boldsymbol{m} ) when it is moving with a constant velocity? A ( . m g ) B. 0 c. ( frac{m}{g} ) D. |
11 |
| 900 | e pulley of the system shown in Fig. onless and thread is inextensible. Illustration 7.37 The pulley of the systei 7.128, is massless and frictionless and thread is The horizontal surface over which block C is placed is smooth while coefficient of friction for all the remaining surfaces is u. Calculate minimum acceleration a with which the system should be moved to the right so that suspended blocks A (mass m) and B(mass M and M>m) can remain stationary relative to C. Fig. 7.128 + means |
11 |
| 901 | limiting friction is of the area of contact.fill in the blank A. directly proportional B. indirectly proportional c. independent D. none |
11 |
| 902 | Who proposed the concept of Inertia? A. Gallileo B. Newton c. Pascal D. Einstein |
11 |
| 903 | 44. Which of the following is correct? a. There is equal probability for the force being conservative or non-conservative. b. Conservative or non-conservative nature of force cannot be predicted on the basis of given information. c. The given force is non-conservative. d. The given force is conservative. |
11 |
| 904 | Find friction force acting on block of mass ( =1 k g ) where ( mu=0.8 ) A . ( 6.8 N ) B. ( 7 N ) ( c .6 N ) D. ( 0 N ) |
11 |
| 905 | If the string is burnt, find the angle between ( A B ) and the vertical at equilibrium position ( A ) B. ( tan ^{-1}left(frac{1}{4}right) ) ( c cdot tan ^{-1}(3) ) ‘ ( quad tan ^{-1}left(frac{1}{2}right) ) |
11 |
| 906 | The friction coefficient between the board and the floor shown in figure (6 E7) is ( mu ). Find the maximum force that the man can exert on the rope so that the board does not slip on the floor. |
11 |
| 907 | A solid cylinder is rolling down on an inclined plane of angle ( theta . ) The coefficient of static friction between the plane and the cylinder is ( mu_{s} ). The condition for the cylinder not to slip is A ( cdot tan theta geq 3 mu_{s} ) B ( cdot tan theta>3 mu_{s} ) c. ( tan theta leq 3 mu_{s} ) ( mathbf{D} cdot tan theta<3 mu_{s} ) |
11 |
| 908 | Rocket works on the principle of conservation of: A. Mass B. Energy c. Momentum D. Velocity |
11 |
| 909 | An inverted T-shaped object is placed on a smooth horizontal floor as shown in figure A force ( boldsymbol{F} ) is applied on the system as shown in figure. The value of ( x ) so that the system performs pure transional motion is A ( cdot frac{L}{4} ) в. ( frac{3 L}{4} ) c. ( frac{L}{2} ) D. ( frac{2 L}{2} ) |
11 |
| 910 | A car is moving on a circular road of curvature ( 300 mathrm{m} . ) If the coefficient of friction is 0.3 and acceleration due to gravity is ( 10 mathrm{m} / mathrm{s}^{2} ), the maximum speed the car can have is: ( A cdot 30 mathrm{km} / mathrm{hr} ) B. 81 km/hr c. ( 108 mathrm{km} / mathrm{hr} ) D. ( 162 mathrm{km} / mathrm{hr} ) |
11 |
| 911 | After an aeroplane completes a voyage, its muzzle feels warmer than the middle and back portion of the main body. This is because: A. the muzzle tears apart the air layers and suffers more air friction B. the muzzle suffers less air friction c. the muzzle suffers zero air friction D. none of these |
11 |
| 912 | Velocity of a particle of mass ( 2 mathrm{Kg} ) varies with time ( t ) according to the equation ( boldsymbol{v}=(mathbf{2} boldsymbol{t} hat{boldsymbol{i}}+boldsymbol{4} hat{boldsymbol{j}}) mathrm{m} / mathrm{s} . ) Here ( mathrm{t} ) is in seconds. Find the impulse imparted to the particle in the time interval from ( t=0 ) to ( t=2 s ) |
11 |
| 913 | 13. In the arrangement shown in Fig. 7.251 pulleys are small light and frictionless, threads are inextensible and mass of blocks A, B, and C is mı = 5 kg, m2 = 4 kg, and mz = 2.5 kg, respectively. Co-efficient of friction for both the planes is u= 0.50. Calculate acceleration of which block when system is released from rest. @=37°NOR Fig. 7.251 |
11 |
| 914 | A man of mass ( 50 ~ k g ) carries a bag of weight ( 40 N ) on his shoulder. The force with which the floor pushes up his feet will be ( mathbf{A} cdot 882 N ) в. ( 530 N ) ( mathbf{c} .90 N ) D. ( 600 N ) |
11 |
| 915 | In the figure, pulleys are smooth and strings are massless ( m_{1}=1 k g ) and ( m_{2}=frac{1}{3} k g . ) To keep ( m_{3} ) at rest, ( m_{3} ) should be A. ( 1 k g ) в. ( frac{1}{2} k g ) c. ( frac{4}{3} k g ) D. ( 2 k ) |
11 |
| 916 | Three concurrent co-planer forces ( 1 mathrm{N}, 2 mathrm{N} ) and ( 3 mathrm{N} ) acting along different directions on a body. A. Can keep the body in equilibrium if ( 2 mathrm{N} ) and ( 3 mathrm{N} ) act at right angle B. Can keep the body in equilibrium if ( 1 mathrm{N} ) and ( 2 mathrm{N} ) act at right angle c. can keep the body in the equilibrium. D. Can keep the body in equilibrium if ( 1 mathrm{N} ) and ( 3 mathrm{N} ) act at an acute angle |
11 |
| 917 | A homogeneous block of mass ( m ), width ( b ) and height ( h ) is resting on a rough horizontal surface. A horizontal force ( boldsymbol{F} ) is applied to it, which makes it to move with a constant velocity. The coefficient of friction between block and surface is ( mu . ) Find the greatest height at which force ( boldsymbol{F} ) may be applied to slide the block without tipping over. ( ^{A} cdot frac{b}{2 mu} ) B. ( frac{2 b}{mu} ) ( c cdot b ) ( bar{mu} ) ( frac{2 sqrt{2} b}{mu} ) |
11 |
| 918 | The friction that exists between a surface sliding over another is called |
11 |
| 919 | A car is moving on a frictionless (in the radial direction) circular banked road, with a banking angle of ( 15^{circ}, ) find the velocity of the car. Mass of car is ( 600 k g ), the radius of the circular road ( =10 m ) Assume ( boldsymbol{g}=mathbf{9 . 8 1} boldsymbol{m} / boldsymbol{s}^{2} ) A. ( 4.26 mathrm{m} / mathrm{s} ) B. ( 5.12 mathrm{m} / mathrm{s} ) c. ( 51.2 mathrm{m} / mathrm{s} ) D. 42.6 m/s |
11 |
| 920 | A rod bent in right angle along its centre line, is placed on a rough horizontal fixed cylinder of radius ( R ) as shown in fig. Mass of rod is ( 2 m ) and rod is in equilibrium. Assume that friction force on rod at ( A ) and ( B ) are equal in magnitude This question has multiple correct options |
11 |
| 921 | When your car takes a sudden turn, you are thrown towards the outer side. Which law explains this process? A. Newton’s third law B. Newton’s second law c. Newton’s first law D. Law of gravitation |
11 |
| 922 | Mark the following statement is true or false. If a ball starts falling from the position of rest, then it travels a distance of ( 25 mathrm{m} ) |
11 |
| 923 | Which of the following utilizes Newton’s third law of motion? A. Archery B. space rocket c. venturimeter D. Internal combustion engine E. Kite flying |
11 |
| 924 | Define the darg? | 11 |
| 925 | A body initially at rest and sliding along a frictionless track from a height ( h ) (as shown in the figure) just completes as vertical of diameter ( boldsymbol{A B}=boldsymbol{D} ). The height ( h ) is equal to: A ( cdot frac{3}{2} D ) в. ( D ) c. ( frac{5}{4} D ) D. ( frac{7}{5} L ) |
11 |
| 926 | 16. A block of masss m = 3 kg is resting over a rough hori. zontal surface having coefficient of friction u = 1/3. The block is pulled to the right by F =21 applying a force F, inclined at angle 37° with the horizontal as m=3 kg shown in Fig. 7.253. The force increases with time according Fig. 7.254 to law F = 2t newton. Calculate its velocity v at t = 10 s. (g = 10 ms?) u=1/3 |
11 |
| 927 | A particle of mass ( m ) is made to move with uniform speed ( v ) along the perimeter of a regular hexagon. Magnitude of impulse applied at each corner is: A . ( m v ) B. ( m v sqrt{3} ) c. ( frac{m v}{2} ) D. ( frac{m v}{sqrt{3}} ) |
11 |
| 928 | Student ( A ) and student ( B ) sit in identical office chairs facing each other, as shown in figure. Student A is heavier than student B. Student A suddenly pushes with his feet. Which of the following occurs? A. Neither student applies a force on each other B. A exerts a force that is applied to B, but A experiences no force c. Each student applies a force to the other, but A exerts the larger force D. The students exert the same amount of force on each other |
11 |
| 929 | A circular road of radius ( 50 mathrm{m} ) has the angle of banking equal to ( 30^{circ} . ) At what speed should a vehicle go on this road so that the friction is not used? ( mathbf{A} cdot 7 m s^{-1} ) B. ( 17 m s^{-1} ) ( mathbf{c} cdot 22 m s^{-1} ) D. ( 27 m s^{-1} ) |
11 |
| 930 | A stone is tied to the middle of a string and suspended from one end as shown in the given figure. Here ( S ) is the stone and 0 is the point of suspension. If we increase the pull at ( mathrm{P} ) gradually, the string will break A. below the stone B. at the point P itself c. above the stone D. nothing can be decided |
11 |
| 931 | Assertion Angle of repose is equal to the angle of limiting friction. Reason When the body is just at the point of motion, the force of friction in this stage is called limiting friction A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
11 |
| 932 | Momentum is a measure of A. Weight B. Mass C . Quantity of motion D. Velocity |
11 |
| 933 | What is momentum? Write its SI unit. Interpret force in terms of momentum Represent the following graphically. |
11 |
| 934 | force that is transmitted through a string, rope, cable etc. When it is pulled by forces acting from opposite ends. A. Normal reaction B. Tension c. Gravitation D. All |
11 |
| 935 | The linear momentum ( P ) of a particle varies with time as follow ( boldsymbol{P}=boldsymbol{a}+boldsymbol{b} boldsymbol{t}^{2} ) Where ( a ) and ( b ) are constants. The net force acting on the particle is: A. Proportional to ( t ) B. Proportional to ( t^{2} ) c. zero D. constant |
11 |
| 936 | A box has to be moved from point ( A ) to point B. Which is the easiest way to move it? A. To push it across the distance B. To slide it using an inclined plane c. To use a wheeled trolley D. To lift it and place it in the desired place |
11 |
| 937 | The coefficient of friction between the tyres and the road is ( 0.1 . ) The maximum speed with which a cyclist can take a circular turn of radius ( 3 mathrm{m} ) without skidding is then (Take ( left.g=10 m s^{-2}right) ) B. ( sqrt{3} mathrm{ms}^{-1} ) D. ( sqrt{10} mathrm{ms}^{-1} ) |
11 |
| 938 | A ball of mass ( 400 mathrm{gm} ) is dropped from a height of ( 5 mathrm{m} ). A boy on the ground hits the ball vertically upwards with a bat with an average force of ( 100 mathrm{N} ) so that it attains a vertical height of ( 20 mathrm{m} . ) The time for which the ball remains in contact with the bat is: ( left[boldsymbol{g}=mathbf{1 0 m} / boldsymbol{s}^{2}right] ) A. ( 0.12 s ) B. ( 0.08 s ) c. ( 0.04 s ) D. 12 |
11 |
| 939 | Illustration 7.14 A block of mass m = 10 kg is to be pulled on a horizontal rough surface with the minimum force. a. At what angle O with horizontal the block should be pulled? b. What is the magnitude of the force F? |
11 |
| 940 | Idea of inertia came from: A. Newton’s third law of motion B. Newton’s second law of motion C. Newton’s first law of motion D. Law of gravitation |
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| 941 | Assertion Inertia is the property by virtue of which the body is unable to change by itself, its state of rest or motion and its direction of motion. Reason The bodies do not change their state unless acted upon by an unbalanced external force A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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| 942 | A particle of mass ( m ) is moving in horizontal circle of radius ( r ) with uniform speed ( v ). When it moves from one point to a diametrically opposite point its A. KE changes by ( m v^{2} ). B. KE changes by ( frac{1}{4} m v^{2} ). c. momentum does not change. D. momentum changes by ( 2 m v ) |
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| 943 | A student pulls a wooden box along a rough horizontal floor (without the block loosing contact with the floor) at constant speed by means of a force ( P ) as shown, to the right. ( (W ) is weight of block, ( N ) is normal reaction on the block, ( f ) is force of friction on the block). Which of the following must be true? A ( . P>f ) and ( Nf ) and ( N=W ) c. ( P=f ) and ( N>W ) ( D<f ) and ( N=W ) |
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| 944 | The property of inertia is more in: ( A cdot ) a car B. a truck ( c . ) a cart D. a toy car |
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| 945 | A box is placed on an inclined plane and has to be pushed down. The angle of inclination is : A. Equal to the angle of friction B. More than the angle of friction c. Equal to the angle of repose D. Less than the angle of repose |
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| 946 | The radius of earth is about ( 6400 mathrm{km} ) and that of mars is ( 3200 mathrm{km} ). Thus mars of the earth is about 10 times mass of mars. An object weighs ( 200 mathrm{N} ) on the surface of earth. Then its weight on the surface of mars will be A. 80 N B. 40 N ( c cdot 20 N ) ( D cdot 8 N ) |
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| 947 | Five identical cubes each of mass ( m ) are on a straight line with two adjacent faces in contact on a horizontal surface as shown in the figure. Suppose the surface is frictionless and a constant force ( boldsymbol{P} ) is applied from left to right to the end face of ( A ; ) which of the following statements are correct? ( mathbf{P} rightarrow )begin{tabular}{|l|l|l|l|l|} hline ( mathbf{A} ) & ( mathbf{B} ) & ( mathbf{C} ) & ( mathbf{D} ) & ( mathbf{E} ) \ hline end{tabular} A the acceleration of the system is ( frac{5 P}{m} ) B. the resultant force acting on each cube is ( frac{P}{5} ) c. the force exerted on D due to C is ( frac{2 P}{5} ) D. the acceleration of the cube ( D ) is ( frac{P}{5} ) m |
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| 948 | Assertio A block of mass ( m ) starts moving on a rough horizontal surface with a velocity ( v . ) It stops due to friction between the block and the surface after moving through a certain distance. The surface is now tilted to an angle of ( 30^{circ} ) with the horizontal and the same block is made to go up on the surface with the same initial velocity ( v ). The decrease in the mechanical energy in the second situation is smaller than that in the first situation. Reason The coefficient of friction between the block and the surface decreases with the increase in the angle of inclination A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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| 949 | 9. The upper surface of block C is horizontal and its right part is inclined to the horizontal at angle 37°. The mass of blocks A and B are m, = 1.4 kg and m, = 3.Kg. respectively. Neglect friction and mass of the pulley Calculate acceleration a with which block C should be moved to the right so that A and B can remain stationary relative to it. a = 2 370 Fig. 6.289 .: C200 |
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| 950 | 35. A block is lying on the horizontal frictionless surface. One end of a uniform rope is fixed to the block which is pulled in the horizontal direction by applying a force Fat the other end. If the mass of the rope is half the mass of the block, the tension in the middle of the rope will be a. F b. 2 F/3 c. 3 F/5 d. 5 F/6 c AcO 1. |
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| 951 | Assertion Mass is a measure of inertia of the body. Reason Greater the mass, greater is the force required to change its state of rest or of uniform motion. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
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| 952 | A body of mass ( 1 k g ) is thrown with a velocity of ( 10 m s^{-1} ) at an angle of ( 60^{circ} ) with the horizontal. Its momentum at the highest point is: ( mathbf{A} cdot 2 mathrm{kg} mathrm{ms}^{-1} ) B. 3 ( k g m s^{-1} ) ( mathbf{c} cdot 4 k g m s^{-1} ) D. 5 kg ( m s^{-1} ) |
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| 953 | Which of the following statements are true? This question has multiple correct options A. Impulse is the product of force and time for which the force acts. B. Sl unit of impulse is ( N ) s C. When two bodies have the same velocity; the lighter body has more momentum. D. Conservation of linear momentum has no connection with “Newton’s third law of motion”” |
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| 954 | A block released from rest from the top of a smooth inclined plane of angle ( boldsymbol{theta}_{mathbf{1}} ) reaches the bottom in time ( t_{1} . ) The same block released from rest from the top of another smooth inclined plane of angle ( theta_{2}, ) reaches the bottom in time ( t_{2} . ) If the two inclined planes have the same height, the relation between ( t_{1} ) and ( t_{2} ) is ( mathbf{A} cdot frac{t_{2}}{t_{1}}=left(frac{sin theta_{1}}{sin theta_{2}}right)^{1 / 2} ) B. ( frac{t_{2}}{t_{1}}=1 ) ( mathbf{C} cdot frac{t_{2}}{t_{1}}=frac{sin n_{1}}{sin theta_{2}} ) ( mathbf{D} cdot frac{t_{2}}{t_{1}}=frac{sin ^{2} theta_{1}}{sin ^{2} theta_{2}} ) |
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| 955 | A particle of mass ( m ) strikes elastically with a disc of radius ( R, ) with a velocity ( vec{v} ) as shown in the figure. If the mass of the disc is equal to that of the particle and the surface of the contact is smooth, then the velocity of the disc just after the collision is: A ( cdot frac{2 v}{3} ) B. ( frac{v}{2} ) c. ( frac{sqrt{3} v}{2} ) D. |
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| 956 | A bullet of mass 60 g moving with a velocity of ( 500 m s^{-1} ) is brought to rest in 0.01 s. Find the impulse and the average force of the blow. | 11 |
| 957 | If brakes are applied all of a sudden in a moving car, passengers automatically lean forward is an example of inertia in motion: Type 1 for true and 0 for false | 11 |
| 958 | From the following statements write down which is not applicable to mass of an object. (a) It is a fundamental quantity. (b) It is measured using physical balance. (c) It is measured using spring balance. |
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| 959 | A uniform rod ( A B ) of mass ( m ) and length is at rest on a smooth horizontal surface. An impulse J is applied to the end B perpendicular to the rod in horizontal direction. Speed of particle ( P ) at a distance I/6 from the centre towards ( A ) of the rod after time ( t=frac{pi m l}{12 J} ) is A ( cdot_{2} frac{J}{m} ) B. ( frac{J}{sqrt{2} m} ) c. ( frac{J}{m} ) D. ( sqrt{2} frac{J}{m} ) |
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| 960 | A block of mass ( 0.1 mathrm{kg} ) is held against a wall by applying a horizontal force of 5 N on the block. If the coefficient of friction the block and the wall is ( 0.5, ) the magnitude of the frictional force acting on the block is: A. ( 2.5 mathrm{N} ) B. 0.98 N c. ( 4.9 mathrm{N} ) D. 10 N |
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| 961 | A particle of mass ( m ) is made to move with uniform speed u along the perimeter of a regular polygon of ( n ) sides. What is the magnitude of impulse applied by the particle at each corner of the polygon? | 11 |
| 962 | An open box of height ( 1 m ) is placed near a ( 2 m ) high table as shown. Marble rolling on the table leaves the table and are collected in the box ( u_{max } ) and ( u_{text {min }} ) are the minimum and maximum values of velocity of marbles to fall into the box. Find the value of ( u_{max }-u_{min }(text { in } boldsymbol{m} / boldsymbol{s}) ) |
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| 963 | A car of mass ( 1000 mathrm{kg} ) rounds a curve of radius ( 250 mathrm{m} ) at ( 90 mathrm{km} / mathrm{hr} ). Cpmpute its, A. Angular speed B. Centripal accelearation c. centripetal accele ration D. Centripetal force. |
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| 964 | To move at same speed, a car with flat face and another with streamlined body will require different amount of force from the engine. The engine of the streamline bodied car will: A. exert less force B. exert more force c. exert zero force D. exert no force |
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| 965 | For how long should a force of ( 100 N ) act on a body of ( 20 k g ) so that is acquires a velocity of ( 100 m s^{-1} ) |
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| 966 | The depressions and elevations present on the surface of objects causes friction. A. True B. False |
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| 967 | A boat with a sail, has an electric fan inside. When the fan starts, the boat A. cannot move B. can move c. moves depending on wind directions D. moves depending on the speed of the fan |
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| 968 | U. TUL POSSIDIC 81. Fig. 8.259 shows a smooth vertical circular track AB of radius R. A block slides along the surface AB when it is given a velocity equal to V6gR at point A. The ratio of the force exerted by the track on the block at point A to that at point B is 60 N6gr Fig. 8.259 b. 0.35 c. 0.45 a. 0.25 d. 0.55 |
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| 969 | A block of mass ( m k g ) is sliding from rest on an inclined rough surface of inclination ( theta ) as shown in the figure under the action of three forces, weight normal and frictional force only. The magnitude of force are ( 20 N, 40 N ) and ( mathbf{5 0} N ) not necessarily in the same order The value of ( g ) is ( 10 m / s^{2} . ) Now match the physical quantity in ( L i s t-I ) with their magnitude in ( L i s t-I I ) in ( S I ) unit and select the correct answer using the codes given below the lists: (assume that the coefficient of kinetic friction is less than 1 ). |
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| 970 | A block has been placed on an inclined plane with the slope angle ( theta ), block slide down the plane at constant speed. The coefficient of kinetic friction is equal to: A ( . sin theta ) B. ( cos theta ) ( c cdot sec theta ) D. ( tan theta ) |
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| 971 | Normal force is a A. Action force B. Reaction force c. Both D. None |
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| 972 | When you walk or run you push your foot ( _{text {一一一一一一一一 }} ) (forwards, backwards) | 11 |
| 973 | A ball of mass ( 3 k g ), moving with a speed of ( 10 m s^{-2} ) strikes a wall at an angle of ( 60^{circ} ) (as shown). The ball rebounds at the same speed. Find the impulse imparted to the ball by the wall |
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| 974 | A ship of mass ( 3 times 10^{7} ) kg, initially at rest, is pulled by a force of ( 5 times 10^{4} N ) through a distance of 3 m. Assuming that the resistance due to water is negligible, the speed of the ship is A ( .1 .5 m / s ) в. ( 60 mathrm{m} / mathrm{s} ) c. ( 0.1 m / s ) D. ( 5 m / s ) |
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| 975 | Assertion When an automobile while going too fast around a curve overturns, its inner wheels leave the ground first. Reason For a safe turn the velocity of automobile should be less than the |
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| 976 | Banking of roads is done due to A. provide enough friction for circular motion of the vehicle B. provide necessary centripetal force required for circular motion of the vehicle C. provide enough radius of curvature for circular motion of the vehicle D. provide enough area for navigating in the circular motion of the vehicle |
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| 977 | A heavy uniform bar is being carried by two men on their shoulders. The weight of the bar is ( w ). If one man lets it fall from the end carried by him, what will be the weight experienced by the other person at the instant when the other man releases the bar? A. ( w / 4 ) в. ( w / 2 ) ( c . w ) D. None of these |
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| 978 | 17. The value of acceleration az at the moment spring PQ is cut is a. 8, downward b. 8, upwards c. More than 8, downwards d. Zero Fig. 6.375 1.. canaleria |
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| 979 | A lift is going up with uniform velocity. When brakes are applied, it slows down. A person in that lift experiences: A. more weight B. less weight c. normal weight D. zero weight |
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| 980 | A block of mass ( 0.18 k g ) is attached to a spring of force constant ( 2 N m^{-1} ). The coefficient of friction between the block and the floor is ( 0.1 . ) Initially, the block is at rest and the spring is un-stretched. An impulse is given to the block as shown in Fig. The block slides a distance of ( 0.06 m ) and comes to rest for the first time. The initial velocity of the block in ( m s^{-1} ) is ( V=N / 10 . ) Then N is : ( A ) B. ( c ) D. |
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| 981 | 2. Wala teloning van u 110 puruuil las least Killeul Clisy a po 2. Which of the following is/are conservative force(s)? a. Ē = 2r3 mense se C. = 3(xi +yj) d. 7 = 3(yi + x j) (x² + y2j3/2 (x² + y2)312 |
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| 982 | A truck and a car are moving on a smooth, level road such that the kinetic energy associated with them is same. Brakes are applied simultaneously in both of them such that equal retarding forces are produced in them. Which one will cover a greater distance before it stops? A . car B. Truck c. Both will cover the same distance D. Nothing can be decided |
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| 983 | You spill a bucket of soapy water on a marble floor accidentally.lt would make it ( _{text {十一一一一一 }} ) for you to walk on the floor. A. more difficult B. easier c. no change D. cant say |
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| 984 | List I contains either an action or an observation. Match each of these, respectively to the correct effect, or a reason from list II. List 1 List II ( a ) . Two rotating discs e. Generated force of in contact- friction is equal to are brought in contact- coaxially b. A contact force exists between exists between a rough surface and body placed on it y placed on it d a partially into heat Attributed to g. resultant of ” ” I reaction and c. For a body on a rough surface, maintaining motion is easier as compared to initiating it normal coefficient of friction between t the surfaces Is ( quad ) h. As kinetic friction ( begin{array}{l}text { d. Static friction is } \ begin{array}{l}text { less than limiting } \ text { friction }end{array} & begin{array}{l}text { h. AS } \ text { is less than static } \ text { friction }end{array}end{array} ) |
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| 985 | … of Roads is done by raising the outer edges of the road slightly above the leve of inner edge, to avoid accidents. A. Finishing B. Banking c. Inclination D. None of these |
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| 986 | The process of walking involves: A. Newton’s first law of motion B. Newton’s second law of motion C. Newton’s third law of motion D. Conservation of momentum |
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| 987 | Which of the following is NOT true? A. A sharp knife can easily cut due to its small cutting surface. B. It is easier to walk in sand than on road. C. A battle tank can move easily on soft ground because its tracks have bigger surface. D. The pressure exerted by a needle is much more than the foot of an elephant. |
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| 988 | 18. Calculate the maximum possible value of mass mo of block C upto which block A will remain stationary relative to B. If the length of block B is equal to l = 50 cm and mass of block C is mz = 2mo, then calculate the time t when block A will topple from Fig. 7.256 block B, if the system is released from rest. |
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| 989 | Unu we plane. 7.239 plock A as shown in Fig. 7.240 weighs 1.40 N. and block B weighs 4.20 N. The coefficient of kineti coefficient of kinetic friction between 11 surfaces is 0.30. Find the magnitude of the horizontal force necessary to drag block B to the left at constant need if A and B are connected by a light, flexible con assing around a fixed, frictionless pulley. F Fig. 7.240 |
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| 990 | A force ( boldsymbol{F} ) is applied on free end of a string such mass of ( 18 k g ) remain stationary. Then value of ( boldsymbol{F} ) will be: ( mathbf{A} cdot 180 N ) B. ( 90 N ) c. ( 60 N ) D. ( 30 N ) |
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| 991 | A man walks on a rough surface, the angle between the force of friction and the instantaneous velocity of the person is : A . ( pi ) в. ( frac{pi}{2} ) c. ( 2 pi ) D. zero |
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| 992 | Which of the following material is likely to have least friction? A. woodd B. Plasticç c. Glass D. Paper |
11 |
| 993 | 18. The value of acceleration a, at the moment string RS is cut is a. 8, downward b. 8, upwards c. More than 8, downwards d. Zero |
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| 994 | In which of the following cases the net force is not zero? A. A kite skillfully held stationary in the sky B. A ball freely falling from a height c. An aeroplane rising upwards at an angle of ( 45^{circ} ) with the horizontal with a constant speed D. A cork floating on the surface of water |
11 |
| 995 | In Fig. ( 1.35, ) a uniform bar of length I ( mathrm{m} ) is supported at its end and loaded by a weight ( mathrm{W} ) kgf at its middle. In equilibrium, find the reactions ( boldsymbol{R}_{1} ) and ( R_{2} ) at the ends. |
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| 996 | When a bullet is fired from a rifle its momentum become ( 20 mathrm{kg} ) m/s. If the velocity of the bullet is ( 1000 m / s ) what will be its mass? A . ( 30 g ) B. ( 5 mathrm{kg} ) c. ( 20 g ) D. ( 500 g ) |
11 |
| 997 | A player caught a cricket ball of mass ( 150 g ) moving with ( 20 mathrm{ms}^{-1} . ) If the catching process is complete in 0.1 sec This question has multiple correct options A. Force exerted by the ball on the hand of player is ( 30 N ) B. Force exerted by the ball on the hand of players is 40 N c. Impulse of the ball is ( 3 N-S ) D. Force exerted by the ball on the hand of players is 50 N |
11 |
| 998 | You tend to slip when step on a banana peel lying on a smooth surface. This is due to: A. increased friction B. reduced friction c. gravity D. characteristics of the banana peel |
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| 999 | Friction reduces efficiency of machines due to: A. Production of heat B. Wearing out of moving parts C. Increase in energy consumption D. All of the above |
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| 1000 | What is meant by the term inertia? A. There is natural tendency for objects to resist changes in their state of motion. B. A measure of an object’s resistance to changes in a rotation direction. C. A force is a push or a pull that acts upon an object as a results of its interaction with another object. D. A measurement of the amount of matter something contains. |
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| 1001 | A man of mass ( m ) walks from end ( A ) to the other end ( B ) of a boat of mass ( M ) and length ( l . ) The coefficient of friction between the man and the boat is ( mu ) and neglect any resistive force between the boat and the water. This question has multiple correct options A. If the man runs at his maximum acceleration, the acceleration of the boat is ( (m / M) g ) B. The maximum time take by the men to reach the other end of the boat is ( sqrt{frac{2 M l}{(M+m) mu g}} ) c. If the man runs at his maximum acceleration, the acceleration of the boat is ( frac{m}{m+M} mu g ) D. The minimum time take by the men to reach the other end of the boat is ( sqrt{frac{2 m l}{(M+m) mu g}} ) |
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| 1002 | Statement 1: When a man is standing on a stationary horizontal surface, the normal force exerted by the ground on him is equal and opposite to his weight. Statement 2: According to Newton’s 3 ( ^{r d} ) law , every action has an equal and opposite reaction. A. Statement 1 – is true, statement- 2 is true and statement-2 is correct explanation for statement- B. Statement 1 – is true, statement- 2 is true and statement-2 is NOT the correct explanation for statement- c. Statement 1 – is true, statement- 2 is false D. Statement 1 – is false, statement- – 2 is true |
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| 1003 | A small mass slides down an inclined plane of inclination ( boldsymbol{theta} ) with the horizontal. The co-efficient of friction is ( mu=mu x ) where ( x ) is the distance through which the mass slides down and ( mu ) a constant. Then the speed is maximum after the masscovers a distance of: A ( cdot frac{cos theta}{mu_{0}} ) B. ( frac{sin theta}{mu_{0}} ) ( c cdot frac{tan theta}{mu_{0}} ) D. ( frac{2 tan theta}{mu_{0}} ) |
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| 1004 | A block is gently placed on a conveyor belt moving horizontally with constant speed. After ( t=4 s, ) the velocity of the block becomes equal to the velocity of the belt. If the coefficient of friction between the block and the belt is ( mu= ) ( 0.2, ) then the velocity of the conveyor belt is ( mathbf{A} cdot 8 m s^{-1} ) B. ( 4 m s^{-1} ) ( mathbf{c} cdot 6 m s^{-1} ) D. ( 18 mathrm{ms}^{-1} ) |
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| 1005 | An aeroplane flies at constant speed in a horizontal straight path. Two horizontal forces act on the plane. One is the thrust of the propellers that pushes it forward, and the other is the force of air resistance that acts in the opposite direction. Then: A. thrust force is more B. air resistance is more c. both thrust by propellers and air resistance are equal D. data insufficient |
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| 1006 | A turn of radius ( 20 m ) is banked for the vehicles going at a speed of ( 10 m s^{-1} . ) If the coefficient of static friction between the road and the tyre is ( 0.4, ) what is the possible speed of a vehicle so that it does not slips down? (Take ( left.g=10 m s^{-2}right) ) A. ( 50 k / h ) в. ( 48 k / h ) c. ( 54 k / h ) D. ( 10 k / h ) |
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| 1007 | Find minimum normal force to be applied by each hand to hold three identical books in a vertical position. Each book in a vertical position. Each book has mass ( mathrm{m} ) and the value of the coefficient of friction between the books as well as between hand the book is ( mu ) |
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| 1008 | A ( 1 mathrm{kg} ) ball drops vertically onto the floor with a speed of ( 25 mathrm{m} / mathrm{s} ) and rebounds with a speed of ( 10 mathrm{m} / mathrm{s} ) What is the impulse acting on the ball? |
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| 1009 | At what distance ( from the left) on the bottom face of the block will the normal reaction act when ( F ) acts at the height ( frac{boldsymbol{H}}{mathbf{2}} ) ? (here, assume no toppling happens) A ( cdot frac{mu_{k} H}{2} ) в. ( frac{b-mu_{k} H}{2} ) c. ( _{b-} frac{mu_{k} H}{2} ) D. ( frac{H}{2 mu_{k}} ) |
11 |
| 1010 | An ice cube floats on water in a beaker with ( frac{9}{10} ) th of its volume submerged under water. What fraction of its volume will be submerged if the beaker of water is taken to the moon where the gravity is ( 1 / 6^{t h} ) that on the earth? ( A cdot frac{9}{10} ) в. ( frac{27}{50} ) ( c cdot frac{2}{3} ) D. zero |
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| 1011 | The limiting value of static friction between two contact surfaces is: A. Proportional to normal force between the surfaces in contact. B. Independent of area of contact C. Depends on the microscopic area of constant magnitude. D. All of the above |
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| 1012 | 45. A fixed U-shaped smooth wire has a semi-circular berions between A and B as shown in Fig. 6.328. A bead of mass m moving with uniform speed y through the wire enters the semicircular bend at A and leaves at B. The average force exerted by the bead on the part AB of the wire is Fig. 6.328 4mv2 a. 0 b. πd 2my? d. None of these πd 1 . 1 |
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| 1013 | Which of the following is true for friction? A. It is necessary to perform many tasks. B. It produces heat. c. It wears out the surfaces in contact D. All of the above |
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| 1014 | Assertion More force is required to push a body up a rough inclined plane than that to move the same body down the same plane Reason The friction always acts parallel to inclined plane downwards A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
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| 1015 | limiting value of static friction is sliding friction. A. less than B. equal to c. more than D. less than or equal to |
11 |
| 1016 | 75. A mass m starting from A reaches B of a frictionless to On reaching B, it pushes the track with a force ea times its weight, then the applicable relation is th a force equal to x h Fig. 8.253 (x+5). a. h=- b. h= = 2 c. h=r (x+1 d. h=- 12 |
11 |
| 1017 | ( frac{sqrt{6}}{frac{4}{5}} ) | 11 |
| 1018 | The momentum of a body of mass 0.5 kg dropped from a certain height (h), when reaches the ground is ( 10 mathrm{N} ) s. The value h is ( _{—} ) m. ( left(g=10 m s^{-2}right) ) A . 20 B . 40 c. 10 D. 80 |
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| 1019 | Though friction can provide necessary centripetal force, the banking of roads is considered as advantageous in highways: A . True B. False |
11 |
| 1020 | A uniform chain is just at rest over a rough horizontal table with its ( frac{I}{eta} ) th part of length hanging vertically. Find the of co-efficient of static friction between the chain and the table. |
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| 1021 | If the length of Rough inclined plane is ( 10 m ) and the value of ( g ) is ( 10 m / s^{2} ) and the Angle of Inclination is ( 30^{circ} ) and coefficient of friction is ( 0.2, ) then the Acceleration of the block is A . 4.13 B. 3.27 c. 1.43 D. 1.34 |
11 |
| 1022 | Fig shows an arrangment of masses hanging from a ceiling. In equilibrium, each rod is horizontal, has negligible mass and extends three times as far to the right of the wire supporting it as to the left. If mass ( m_{4} ) is ( 48 mathrm{kg} ) then mass of ( m_{1} ) is equal to A . ( 1 k g ) в. ( 2 k g ) ( c .3 k g ) D. ( 4 k g ) |
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| 1023 | 29. Find the absolute acceleration of block 4. a. 2 ms-2 upwards b .1 ms 2 downwards c. 3 ms-2 downwards d. 1.5 ms upwards |
11 |
| 1024 | Light in certain cases may be considered as a stream of particles called photons. Each photon has a linear nomentum ( frac{h}{lambda} . ) where ( h ) is the Planck’s constant and ( lambda ) is the wavelength of the light.A beam of light of wavelength ( lambda ) is incident on a plane mirror at an angle of incidence ( theta ). Calculate the change in linear momentum of photon as the beam is reflected by the mirror |
11 |
| 1025 | Two bodies of mass m and ( 4 mathrm{m} ) are attached with string as shown in the figure. The body of mass m hanging from a string of length I is executing oscillations of angular amplitude ( boldsymbol{theta}_{mathbf{0}} ) while the other body is at rest. The minimum coefficient of friction between the mass ( 4 mathrm{m} ) and the horizontal surface should be ( mathbf{A} ) B ( cdot 2 cos ^{2}left(frac{theta_{0}}{2}right) ) c. ( left(frac{1-cos theta_{0}}{3}right) ) D. |
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| 1026 | Two balls of same mass are dropped from the same height ( h, ) on to the floor. The first ball bounces to a height ( h / 4 ) after the collision and the second ball to a height ( h / 16 . ) The impulse applied by the first and second ball on the floor are ( I_{1} ) and ( I_{2} ) respectively. Find the ratio ( frac{I_{1}}{I_{2}} ) |
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| 1027 | Fill in the blank. Water offers fluid friction as compared to honey. A. higher B. lower c. same D. zero |
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| 1028 | When a block of mass ‘ ( m^{prime} ) is released from point ( ^{prime} boldsymbol{A}^{prime} ) on the surface of a smooth bowl, the normaal reaction on it ( B ) would be equal to ( mathbf{A} cdot m g ) B. ( 2 m g ) c. ( 3 m g ) D. Zero |
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| 1029 | Student ( A ) and student ( B ) sit in identical office chairs facing each other, as shown in figure. Student A is heavier than student B. Student A suddenly pushes with his feet. Which of the following statements is correct? A. Both A and B will move in same direction B. B will move to right while A will not move c. A will move to right while B will move to let D. A and B will move in opposite directions |
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| 1030 | A block of mass ( m ) slides down the plane inclined at an angle 60 with an acceleration ( frac{g}{2} . ) Find the coefficient of kinetic friction? |
11 |
| 1031 | When a running horse suddenly stops, the rider falls forwards. A. True B. False |
11 |
| 1032 | Physical independence of force is a consequence of A. First law of motion B. Second law of motion c. Third law of motion D. All of these laws |
11 |
| 1033 | n the arrangement shown in figure above the mass of body 1 is ( eta=0.4 ) times as great as that of body 2 . The height ( h=20 mathrm{cm} . ) The masses of the pulleys and the threads, as well as the friction are negligible. At a certain moment body 2 is released and the arrangement set in motion. Find the maximum height that body 2 will go up to in ( mathrm{cm} ) |
11 |
| 1034 | Assertion A cloth covers a table. Some dishes are kept on it. The cloth can be pulled out without dislodging the dishes from the table Reason For every action, there is an equal and opposite reaction. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
11 |
| 1035 | A child weighing 25 kg slides down a rope hanging from a branch of a tall free. If the force of friction acting against him is ( 200 N ), the acceleration of child is ( left(boldsymbol{g}=mathbf{1 0} boldsymbol{m} / boldsymbol{s}^{2}right) ) A ( cdot 22.5 mathrm{m} / mathrm{s}^{2} ) B . ( 8 mathrm{m} / mathrm{s}^{2} ) c. ( 5 m / s^{2} ) D. ( 2 m / s^{2} ) |
11 |
| 1036 | Give reasons A heavy truck is filled with 6 to 14 wheels. |
11 |
| 1037 | A cannon ball of mass ( 500 g ) is fired with a speed of ( 15 m s^{-1} ). Find its momentum. A . ( 7500 k g ) m ( s^{-1} ) B. ( 3750 k g ) m ( s^{-1} ) c. ( 7.5 k g m s^{-1} ) D. 3.75kg m s ( ^{-1} ) |
11 |
| 1038 | Identify which of the following quantity describe object’s resistance to change in motion. A. acceleration B. velocity c. mechanics D. force E. inertia |
11 |
| 1039 | 48. In Fig. 6.331, the block of mass M is at rest on The acceleration with which a boy of mass m show along the rope of negligible mass so as to lift the from the floor is rest on the floor sm should climb lift the block m Fig. 6.331 M – -118 (m M d. > M d. > |
11 |
| 1040 | A man throws a ball weighing ( 500 g ) vertically upwards with a speed of ( 10 m / s ) (i) what will be its initial momentum? (ii) What would be its momentum at the highest point of its flight? |
11 |
| 1041 | A 50 kg crate is being pushed across a horizontal floor by a horizontal force of ( 575 mathrm{N} ). If the coefficient of sliding friction is ( 0.25, ) what is the acceleration of the crate? |
11 |
| 1042 | The speed of the bicycle is ( begin{array}{ll}text { A. } 6.4 pi m & s^{-1}end{array} ) B. ( 3.5 pi m quad s^{-1} ) ( mathbf{c} cdot 2.8 pi m quad s^{-1} ) ( begin{array}{ll}text { D. } 5.6 pi m & s^{-1}end{array} ) |
11 |
| 1043 | There are 3 balls of same shape and size made of wood, iron and plastic. Which one of them would have highest inertia? A. wood B. Iron c. Plastic D. None of these |
11 |
| 1044 | A road is 10 mwide. Its radius of curvature is ( 50 m ). The outer edge is above the lower edge by a distance of 1./5m. This road is most suited for the velocity A. ( 2.5 mathrm{m} / mathrm{sec} ) B. ( 4.5 mathrm{m} ) sec c. ( 6.5 m ) sec D. ( 8.5 m ) sec |
11 |
| 1045 | How is a speed skater able to glide across the ice? How can the skater increase friction between the ice and the skates? What effect does an increase in friction have on the skater’s speed? |
11 |
| 1046 | A block of mass ( 15 mathrm{kg} ) is resting on a rough inclined plane as shown in figure The block is tied up by a horizontal string which has a tension of 50N. Calculate the coefficient of friction between the block and inclined plane. |
11 |
| 1047 | Assertion A car moving on a horizontal rough road with velocity ( v ) can be stopped in a minimum distance ( d ). If the same car moving with same speed ( v ) takes a circular turn, then minimum safe radius can be ( 2 d ) Reason ( d=frac{v^{2}}{2 mu g} ) and minimum safe radius ( = ) ( boldsymbol{v}^{2} ) ( mu g ) A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion is incorrect and Reason is correct |
11 |
| 1048 | Illustration 7.7 A block of mass 2 kg is pushed normall, against a rough vertical wall with a force of 40 N, co-effici of static friction being 0.5. Another horizontal force of 15 N is applied on the block in a direction parallel to the #15NL wall. Will the block move? If yes, in 40 N which direction and with what mg acceleration? If no, find the frictional force exerted by the wall on the Fig. 7.20 block. NHHHHHHHHI |
11 |
| 1049 | A circular smooth road of radius ( r= ) ( 20 m ) is banked for vehicles moving at a speed of ( v=36 k m p h ). If the friction coefficient between the road and the road and the Tyre is ( 0.3, ) find the maximum speed of a vehicle going around this curved road. A. ( 29.39 k m p h ) в. ( 39.29 k ) три c. ( 40.39 k m p h ) D. None of these |
11 |
| 1050 | A smooth ball of mass ( m ) strikes a horizontal surface with a velocity ( v ) in a direction making an angle ( 30^{circ} ) with the normal to the surface as shown in figure. If the coefficient of restitution for the collision between the ball and the surface is ( e ) and the ball was in contact with the surface for a small time ( Delta t, ) the average force acting on the ball during collision is ( mathbf{A} cdot m g ) B. ( frac{m v(1+e)}{2 Delta t} ) c. ( sqrt{3} frac{m v(1-e)}{2 Delta t} ) D. ( sqrt{3} frac{m v(1+e)}{2 Delta t} ) |
11 |
| 1051 | State whether the given statement is true or false : Friction is a necessary evil. A. True B. False |
11 |
| 1052 | A body of mass ( m ) is released from the top of a rough inclined plane length ( l ). If the frictional force is ( f, ) and the height of body from ground is ( h ) then the velocity of the body of the bottom in ( boldsymbol{m} boldsymbol{s}^{-1} ) will be : A ( cdot sqrt{frac{2}{m}(m g h-f l)} ) в. ( 2 g h-f / l ) c. ( sqrt{frac{2}{m} g h} ) D. zero |
11 |
| 1053 | A body of mass 100 g is sliding from an inclined plane of inclination ( 30^{0} ). What is the frictional force experienced if ( mu=0.7 ? ) A. ( 0.35 times sqrt{3} ) B. ( c cdot frac{sqrt{3}}{2} ) D. 0.35 |
11 |
| 1054 | The mass of a lift is 2000 kg. When the tension in the supporting cable is ( 28000 mathrm{N}, ) then its acceleration is A ( cdot 30 mathrm{ms}^{-2} ) downwards B. ( 4 mathrm{ms}^{-2} ) upwards c. ( 4 mathrm{ms}^{-2} ) downwards D. ( 14 mathrm{ms}^{-2} ) upwards |
11 |
| 1055 | Find the maximum velocity of the bar over its motion. A ( cdot v_{max }=sqrt{frac{g}{a} cos alpha tan alpha} ) B. ( v_{max }=sqrt{frac{2 g}{a} sin alpha tan alpha} ) c. ( v_{m a x}=sqrt{frac{g}{a} sin alpha tan alpha} ) D. ( v_{max }=sqrt{frac{2 g}{a} cos alpha tan alpha} ) |
11 |
| 1056 | A system of ( n ) particles is free from any external force. Which of the following is true for the magnitude of the total momentum of the system? A. It must be zero B. It could be non-zero, but it must be constant c. It could be non-zero, and it might not be constant D. The answer depends on the nature of the internal forces in the system |
11 |
| 1057 | When two surfaces are polished, the friction coefficient between them decreases. But the friction coefficient increases and becomes very large if the surfaces are made highly smooth. Explain. |
11 |
| 1058 | Impulse is A. a scalar quantity B. a vector quantity C. neither a scalar nor a vector D. sometimes a scalar and sometimes a vector |
11 |
| 1059 | A mass of ( 200 g m ) has initial velocity ( V_{i}=2 hat{i}+3 hat{j} ) and final velocity ( -2 hat{i}-3 hat{j} ) Find magnitude of change in momentum. A ( cdot|Delta vec{p}|=3.84 ) В . ( |Delta vec{p}|=3.04 ) c. ( |Delta vec{p}|=1.44 ) D . ( |Delta vec{p}|=2.04 ) |
11 |
| 1060 | A 5000 kg rocket is set for vertical firing. The exhaust speed is ( 800 mathrm{ms}^{-1} ) To give an upward acceleration of ( 20 mathrm{ms} ) ( -2, ) the amount of gas ejected per second to supply the needed thrust is ( left(g=10 m s^{-2}right) ) A . ( 127.5 mathrm{kg} mathrm{s}^{-1} ) B . ( 137.5 mathrm{kg} mathrm{s}^{-1} ) c. ( 187.5 mathrm{kg} mathrm{s}^{-1} ) D. ( 185.5 mathrm{kg} mathrm{s}^{-1} ) |
11 |
| 1061 | A rubber ball of mass 250 g hits a wall normally with a velocity ( 10 m s^{-1} ) and bounces back with a velocity of ( 8 m s^{-1} . ) The impluse is ( -dots-dots–N ) s. A. -0.5 в. +0.5 c. -4.5 D. +4.5 |
11 |
| 1062 | 3. Statement I: A particle is found to be at rest when seen from a frame S, and moving with a constant velocity when seen from another frame S2. We can say both the frames are inertial. Statement II: All frames moving uniformly with respect to an inertial frame are themselves inertial. ain . Th e niont of friction can be renter |
11 |
| 1063 | Two blocks of masses ( boldsymbol{m}_{1}=mathbf{5} k boldsymbol{g} ) and ( m_{2}=6 k g ) are connected by a light string passing over a light frictionless pulley as shown. The mass ( m_{1} ) is at rest on the inclined plane and mass ( m_{2} ) hangs vertically. If the angle of incline ( boldsymbol{theta}=mathbf{3 0}^{mathbf{0}} ) what is magnitude and direction of force of friction on the ( 5 mathrm{kg} ) block ( left(g=10 m s^{-2}right) ) A. 35 N up the plane B. 35 N down the plane c. 85 N up the plane D QEN down the plane |
11 |
| 1064 | Show that Newton’s third law of motion is contained in his second law. State and explain the principle of conservation of angular momentum |
11 |
| 1065 | China wares are wrapped in straw or paper before packing. This is the application of concept of : A. Impulse B. Momentum c. Acceleration D. Force |
11 |
| 1066 | Which of the following statements is NOT true for friction force? A. Friction force is produced when two objects rub against each other B. A lighter object will experience a smaller frictional force C. Friction produces more wear and tear D. Friction is harmful |
11 |
| 1067 | When a bomb explodes into two pieces, they move in opposite directions. This motion in opposite direction can be explained by A. Law of conservation of energy B. Law of conservation of momentum c. Law of conservation of mass D. Law of conservation of charge |
11 |
| 1068 | riy. 0.301 7. A car travelling on a smooth road passes through a curved portion of the road in the form of an arc of circle of radius 10 m. If the mass of car is 120 kg, find the reaction in KN) on car at lowest point P where its speed is 20 ms Fig. 8.302. |
11 |
| 1069 | A given object takes ( n ) times more time to slide down ( 45^{circ} ) rough inclined plane as it takes to slide down a perfectly ( operatorname{smooth} 45^{circ} ) incline. The coefficient of kinetic friction between the object and the incline is: A ( cdot frac{1}{2-n^{2}} ) B. ( 1-frac{1}{n^{2}} ) c. ( sqrt{1-frac{1}{n^{2}}} ) D. ( sqrt{frac{1}{1-n^{2}}} ) |
11 |
| 1070 | Assertion When a bus starts suddenly, a person standing in it falls backwards. Reason It is due to inertia of rest. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
11 |
| 1071 | A uniform rod of mass ( 15 k g ) is held stationary with the help of a light string as shown in fig. ( boldsymbol{L}=mathbf{5} boldsymbol{m}, ) angle between rod and ground is ( 37^{0} . ) The tension in the string is : A . ( 150 N ) B. ( 225 N ) c. ( 100 N ) D. None of these |
11 |
| 1072 | Which of the following statements for a rigid object undergoing pure translational motion are false? This question has multiple correct options A. If an object receives an impulse its kinetic energy must change. B. An object’s kinetic energy can change without the object changing momentum. C. An object can receive a net impulse without any work being done on it D. A force may do work on an object without delivering any change in momentum. |
11 |
| 1073 | The weight of a body would not be zero: A. at the centre of the earth B. during a free fall c. in interplanetary space D. at the surface of the earth |
11 |
| 1074 | To avoid slipping while walking on ice, one should take smaller steps because: A. frictional force of ice is large B. of larger normal reaction c. frictional force of ice is small D. of smaller normal reaction |
11 |
| 1075 | A panda with a mass of ( 90.0 k g ) lies without moving on a ramp that is inclined at ( 25.0^{circ} ) What is the coefficient of static frictional force between the ramp and the panda? A . 0.25 B. 0.423 ( c cdot 0.466 ) D. 372 E. The coefficient of static friction cannot be determined with the information giver |
11 |
| 1076 | ( 5 k g ) block rests on horizontal surface. Which of the following option is incorrect? ( left(boldsymbol{g}=mathbf{1} mathbf{0} mathbf{m} / mathbf{s}^{mathbf{2}}right) ) This question has multiple correct options A. The normal force on the block equals its weight because of Newton’s second law B. The normal force on the block is equal to the weight not because of Newton’s third law C. The normal force on the block equals its weight because of Newton’s third law D. The normal force on the block is 50 N. |
11 |
| 1077 | 3. Just after burning the thread, what is the acceleration of m₂? a. (m.-mi & m2 b. m.-m2/8 my + m₂, m-m2 c. Zero m2 |
11 |
| 1078 | Illustration 7.48 A circular track has a radius of 10 m, vehicle goes round it at an average speed of 18 K should be the proper angle of banking. id it at an average speed of 18 kmh-, what |
11 |
| 1079 | A block released from rest from the top of a smooth inclined plane of angle ( boldsymbol{theta}_{mathbf{1}} ) reaches the bottom in time ( t_{1} ). The same block released from rest from the top of another smooth inclined plane of angle ( theta_{2}, ) reaches the bottom in time ( t_{2} ). If the two inclined planes have the same height, the relation between ( t_{1} ) and ( t_{2} ) is ( A ) [ frac{t_{2}}{t_{1}}=left(frac{sin theta_{1}}{sin theta_{2}}right)^{1 / 2} ] B. ( frac{t_{2}}{t_{1}}=1 ) c. ( frac{t_{2}}{t_{1}}=left(frac{sin theta_{1}}{sin theta_{2}}right) ) D. [ frac{t_{2}}{t_{1}}=left(frac{sin ^{2} theta_{1}}{sin ^{2} theta_{2}}right) ] |
11 |
| 1080 | Explain the mechanism behind Motion of a Rocket. |
11 |
| 1081 | The efficiency of machine is reduced due to friction. A. True B. False c. Ambiguous D. Data insufficient |
11 |
| 1082 | A ( 2 k g ) block is placed over a ( 4 k g ) block and both are placed on a smooth horizontal surface. The coefficient of friction between the blocks is ( 0-20 ) Find the acceleration of the two blocks if a horizontal force of ( 12 N ) is applied to (a) the upper block, (b) the lower block. Take ( g=10 m / s^{2} ) |
11 |
| 1083 | An iron block of side ( 50 c m times 8 c m times ) ( 15 c m ) has to be pushed along the floor. The force required will be minimum when the surface in contact with ground is: A. ( 8 c m times 15 c m ) surface B. ( 5 mathrm{cm} times 15 mathrm{cm} ) surface ( mathrm{c} .8 mathrm{cm} times 5 mathrm{cm} ) surface D. force is same for all surfaces |
11 |
| 1084 | A wooden piece is balanced by a brass weight in a sensitive balance. Now the pan contained by wooden piece is covered by a bell jar and then evacuated; A. the pan containing the wooden piece will go up B. the pan containing the wooden piece will go down c. the beam will remain horizontal D. nothing can be said definitely |
11 |
| 1085 | The force of friction acting on a body when velocity is ( 4 m s^{-1} ) is ( 8 N . ) The force of friction when the velocity is ( 8 m s^{-1} ) is ( A cdot 4 N ) B. 8 N ( c cdot 16 N ) D. 32 N |
11 |
| 1086 | Two equal forces to ( P ) and ( 2 P ) act on a particle.If the first be doubled and the second be increased by ( 20 mathrm{N} ), the direction of the resultant is unaltered.Find the value of ( P ) |
11 |
| 1087 | Example 7.13 A thin uniform rod of length I and rotates uniformly with an angularly velocity o in a bo plane about a vertical axis passing through one of Determine the tension in the rod as a function of the a x from the rotation axis. and mass m in a horizontal One of its ends of the distance +T+ AT I dxi Fig. 7.238 |
11 |
| 1088 | Iwo blocks of masses m and M are connected by a chord pessing around a frictionless polley which is attached to a rotating frame, which rotates about a vertical atis with an angular velocity @ If the coefficient of friction be- tween the two masses and the surface are u, and u respec- tively, determine the value of @ at which the block starts Fig. 7.246 sliding radially (M>m). |
11 |
| 1089 | Aeroplanes are streamlined to reduce: A. fluid friction B. sliding friction. c. kinetic friction D. limiting friction. |
11 |
| 1090 | limiting friction is also celled as | 11 |
| 1091 | A uniform chain of mass ( M ) and length ( boldsymbol{L} ) is held vertically in such a way that its lower end just touches the horizontal floor. The chain is released from rest in this position. Any portion that strike the floor comes to rest. Assuming that the chain does not form a heap on the floor, calculate the force exerted by it on the floor when a length ( x ) has reached the floor |
11 |
| 1092 | A bullet of mass ( 1 times 10^{-2} k g ) moving horizontally with a velocity of ( 2 times ) ( 10^{2} m s^{-1} ) strikes a block of mass ( 1.99 k g ) and gets embedded into it. If the coefficient of kinetic friction between the block and the horizontal surface is ( 0.25, ) then the distance moved by the block with the bullet before coming to rest is A. ( 0.4 mathrm{m} ) в. ( 0.8 mathrm{m} ) ( c cdot 0.6 m ) D. ( 0.2 mathrm{m} ) |
11 |
| 1093 | 7. Statement I: Pulling [Fig. 6.366(a)] is easier than pushing [Fig. 6.366(b)] on a rough surface. Fi F2 (a) Fig. 6.366 Statement II: Normal reaction is less in pulling than in pushing. 1 |
11 |
| 1094 | An external force ( F ) acts horizontally on a box of mass ( m ) at a height ( h ). If the ( C M ) of the box is situated at a height ( c ) find the: minimum value of ( F ) so as to topple the box ( ^{A} cdot frac{m g b}{2 h} ) в. ( frac{m g b}{b} ) ( c cdot frac{m g b}{3 b} ) D. ( frac{m g b}{4 b} ) |
11 |
| 1095 | Greater the mass, greater is the inertia of the body. Type 1 for true and 0 for false | 11 |
| 1096 | The figure shows an estimated force time graph for a baseball stuck by a bat From the curve determine: (i) impulse delivered to the ball (ii) force exerted on the ball (iii) the max. force on the ball. |
11 |
| 1097 | A ball of mass m strikes a rigid wall with speed u and rebounds with the same speed. The impulse imparted to the ball by the wall is: A. 2mu в. mu c. zero D. -2mu |
11 |
| 1098 | A cricket ball is rolled on ice with a velocity of ( 5.6 ~ m / s ) and comes to rest after traveling 8 m. Find the coefficient of friction. Given ( boldsymbol{g}=mathbf{9 . 8} boldsymbol{m} / boldsymbol{s}^{2} ) |
11 |
| 1099 | Friction is needed to produce motion or prevent motion. Which of the following statements suits for each application shown in fig (i) and fig (ii)? why? |
11 |
| 1100 | State whether given statement is True or False. Linear momentum is always in the direction of velocity A. True B. False |
11 |
| 1101 | When a ball of mass 5 kg hits a bat with a velocity of ( 3 mathrm{m} / mathrm{s}, ) in a positive direction and it moves back with a velocity of ( 4 mathrm{m} / mathrm{s}, ) find the impulse in ( mathrm{S} ) units. A. 5 B . 15 ( c cdot 25 ) D. 35 |
11 |
| 1102 | A surface is hit elastically and normally by n balls per unit time. All the balls have same mass ( mathrm{m} ) and moves with the same velocity u. The force on the surface is : A ( cdot 1 / 2 ) mnu ( ^{2} ) B. mnu ( ^{2} ) ( c cdot 2 m n u^{2} ) D. 2 mnu |
11 |
| 1103 | Two blocks of same mass ( (4 mathrm{kg}) ) are placed according to diagram. Initial velocities of bodies are ( 4 mathrm{m} / mathrm{s} ) and ( 2 mathrm{m} / mathrm{s} ) and the string is taut. Find the impulse on 4 kg when the string again becomes taut. A ( .24 mathrm{N}-mathrm{s} ) B. ( 6 N- ) s ( c cdot 4 N-s ) D. 2 N-s |
11 |
| 1104 | The change in momentum of a vehicle weighing 2000 kg when its speed increases from ( 36 mathrm{km} / mathrm{h} ) to ( 72 mathrm{km} / mathrm{h} ) uniformly is : A. ( 15000 mathrm{kg}, mathrm{m} / mathrm{s} ) B. 4000 kg.m/s c. ( 20000 mathrm{kg}, mathrm{m} / mathrm{s} ) D. 7200 kg.m/s |
11 |
| 1105 | A cricketer draws his hands backwards to catch the ball, because A. by increasing the time in which he stops the ball, he reduces the force on his hands B. by increasing the distance, he allows the ball to travel a greater distance for more runs C. it is an art to catch the ball D. it is a rule in cricket |
11 |
| 1106 | 7. Block A has a mass of 30 kg and block B a mass of 15 kg. The coefficients of friction between all surfaces of contact are pe = 0.15 and Mr = 0.10. Knowing that 0= 30° and that the magnitude of the force F BI applied to block A is 250 N. Determine (a) acceleration of block A and (b) the tension in Fig. 7.242 the rope. nic placed on a smooth surface |
11 |
| 1107 | Which has a greater momentum, an elephant at rest or an ant in motion? A. Elephant B. Ant c. Neither has momentum D. Same |
11 |
| 1108 | Assertion Angle of repose is equal to angle of limiting friction. Reason When the body is just about to move, the force of friction in this stage is called as limiting friction. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
11 |
| 1109 | Illustration 6.25 A bead of mass m is fitted on to a rod and can move on it without friction. At the initial moment the bead is in the middle of the rod. The rod moves translationally in a horizontal plane with an acceleration a in a direction forming an angle a with the rod. Find the acceleration of the bead relative to the rod. Fig. 6.73 |
11 |
| 1110 | 1. Block B, of ma = 1.5 kg, which shown in Fig. 7.357 bek B, of mass mp=0.5 kg, rests on block A, with mass 15kg, which in turn is on a horizontal tabletop (as in Fig. 7.352). The coefficient of kinetic friction een block A and the tabletop is ur = 0.4 and the fficient of static friction between block A and block B . 0.6. A light string attached to block A passes over frictionless, massless pulley and block C is suspended from the other end of the string. What is the largest mass m (in kg) that block C can have so that blocks A and B still lide together when the system is released from rest? Fig. 7.352 |
11 |
| 1111 | A block of mass ( 15 mathrm{kg} ) is placed on a long trolley The coefficient of friction between the block and trolley is 0.18 The trolley accelerates rest with ( 0.5 mathrm{m} / ) ( s^{2} ) for 20 s then what is the friction force A. 3.5 N B. 133.3 N ( c cdot 7.5 mathrm{N} ) D. N.O.T |
11 |
| 1112 | Assertion We can live very happily if the friction is not present in nature. Reason Aeroplane shape is stream lined to reduce the effort of frictional force. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
11 |
| 1113 | The force of friction is normal reaction between the surfaces. |
11 |
| 1114 | A thin uniform rod of mass ( M ) and length ( L ) is hinged at its upper end released from rest in horizontal position. The tension at a point located at a point located at a point, when the rod becomes vertical, will be: A ( cdot frac{22 M g}{27} ) в. ( frac{11 M g}{13} ) c. ( frac{6 M g}{11} ) ( mathbf{D} cdot 2 M q ) |
11 |
| 1115 | Two identical ladders are arranged as shown in the figure. Mass of each ladder is ( M ) and length ( L ). The system is in equilibrium. Find direction and magnitude of friction force acting at ( mathbf{A} ) or B. A ( cdot f=left(frac{M+m}{2}right) g tan theta ) horizontally outwards B. ( f=left(frac{M+m}{2}right) g cot theta ) horizontally inwards ( ^{mathrm{C}} cdot f=left(frac{M+m}{2}right) g cos theta ) horizontally outwards D. None of these |
11 |
| 1116 | 23. A lift is moving down with an acceleration a. A man in the lift drops a ball inside the lift. The acceleration of the ball as observed by the man in the lift, and a man standing stationary on the ground are, respectively, a. a, 8 b. (8-a); 8 c. a, a d. 8,8 |
11 |
| 1117 | A body takes time ( t ) to reach the bottom of an inclined plane of angle ( theta ) will the horizontal. if the plane made rough, time takes now is ( 2 t . ) The coefficient of frcition of the rough surface is A ( cdot frac{3}{4} tan theta ) B. ( frac{1}{2} tan theta ) c. ( frac{2}{5} tan theta ) D. ( frac{1}{4} tan theta ) |
11 |
| 1118 | A block of mass ( m ) slides in an inclined right angled trough as shown in figure. If coefficient of kinetic friction between block and material composing the trough is ( mu_{k}, ) find the acceleration of the block. |
11 |
| 1119 | A uniform meter sticks of mass 200 g is suspended from the ceiling through two verticle strings of equal lengths fixed at the ends. A small object of 20 g is placed on the stick at a distance of 70 ( mathrm{cm} ) from the left end. Find the tension in the two strings. A ( cdot T_{1}=1.06 N, T_{2}=1.14 N ) B . ( T_{1}=1.03 N, T_{2}=1.17 N ) C . ( T_{1}=1.10 N, T_{2}=1.10 N ) D. ( T_{1}=1.00 N, T_{2}=1.20 N ) |
11 |
| 1120 | is a self adjusting force. A. Magnetic Force B. Electrostatic Force C. Frictional Force D. All |
11 |
| 1121 | A body is projected up along the rough inclined plane from the bottom with some velocity. It travels up the incline and then returns back. If the time of ascent is ( t_{a} ) and time of descent is ( t_{d} ) then ( mathbf{A} cdot t_{a}=t_{d} ) в. ( t_{a}>t_{d} ) c. ( t_{a}<t_{d} ) D. Data in-sufficient |
11 |
| 1122 | Mention three methods of reducing friction in a machine | 11 |
| 1123 | Which will have move inertia? A. A plastic eraser B. Pencil ( c ). A book D. A table |
11 |
| 1124 | Ulustration 7.28 Let us consider the next case in the previous osstration when there is no friction ween ground and M. The coefficients f static and kinetic friction are u, and up M espectively, and force Facts on upper Fig. 7.97 block as shown in Fig. 7.97. . What is the maximum possible value of F so that the system moves together? b. If there is relative sliding between Mand m, then calculate acceleration of M and m. |
11 |
| 1125 | Even through the magnitudes at action force and reaction force are equal and their direction are opposite, their effects do not get cancelled, |
11 |
| 1126 | A body of mass ( 1 mathrm{kg} ) has a kinetic energy of motion 8 J. Its linear momentum is equal to: A ( cdot 2 k g m s^{-1} ) B. ( 4 k g m s^{-1} ) c. ( 6 k g m s^{-1} ) D. ( 8 k g m s^{-1} ) |
11 |
| 1127 | Graphite powder is used in machines to A. Enhance friction B. Enhance profit c. Reduce friction D. Reduce efficiency |
11 |
| 1128 | A person is moving on a rough horizontal surface towards east. Then the direction of friction force is towards A. west B. east c. north D. cant say depends on the situation |
11 |
| 1129 | A uniform stick of mass ( mathrm{M} ) is placed in a frictionless well as shown in the figure. The stick makes an angle ( theta ) with the horizontal. Then the force which the vertical wall exerts on right end of stick is : A ( cdot frac{M g}{2 cot theta} ) в. ( frac{M g}{2 tan theta} ) c. ( frac{M g}{2 cos theta} ) D. |
11 |
| 1130 | State newton’s second law of motion and give related expression why does a cricket player lower his hands while catching the ball? |
11 |
| 1131 | Find out displacement of B till velocity becomes equal A. ( 7.5 mathrm{m} ) B. 10 ( c cdot 13.25 mathrm{m} ) D. ( 12.5 mathrm{m} ) |
11 |
| 1132 | Is larger surface area break on a bicycle wheel more effective than small surface area brake? Explain? |
11 |
| 1133 | Illustration 6.32 Two blocks A and B of mass M& connected through a light string. One end of the string nected to the block B and its other end is connected to point S as shown in Fig. 6.144. Now a force F is app block B. Find the acceleration of block A & B. s M & 3M are e string is con vected to a fixed F is applied to + F 3M Fig. 6.144 |
11 |
| 1134 | By a bullet fire by a gun is more dangerous then bullet fire with medium speed? Explain it properly |
11 |
| 1135 | A car is travelling along a circular curve that has a radius of ( 50 mathrm{m} ). If its speed is ( 16 mathrm{m} / mathrm{s} ) and is incrcasing uniformly at ( 8 m / s^{2} . ) Determine the magnitude of its acceleration at this instant. A ( cdot 7.5 m s^{-2} ) B. ( 8.5 m s^{-2} ) c. ( 9.5 m s^{-2} ) D. ( 9.8 m s^{-2} ) |
11 |
| 1136 | Two bodies have same mass and speed, then: A. their momentums are same B. the ratio of momentums is not determined C. the ratio of their magnitudes of momentum is one D. both (B) and (C) are correct |
11 |
| 1137 | Define Friction: | 11 |
| 1138 | Friction reduces efficiency of machines due to: A. production of heat B. wearing out of moving parts C. increase in energy consumption D. all of the above |
11 |
| 1139 | A car of mass ( 100 mathrm{kg} ) moves on a circular track of radius ( 20 mathrm{m} ). If the coefficient of friction is ( 0.64, ) then the maximum velocity with which the car can move is A. ( 22.4 mathrm{m} / mathrm{s} ) B. ( 5.6 mathrm{m} / mathrm{s} ) c. ( 11.3 mathrm{m} / mathrm{s} ) D. 20 ( mathrm{m} / mathrm{s} ) |
11 |
| 1140 | A metal ball does not rebound when struck on a wall, whereas a rubber ball of same mass when thrown with the same velocity on the wall rebounds. From this it is inferred that: A. change in momentum is same in both. B. change in momentum in rubber ball is more. c. change in momentum in metal ball is more D. initial momentum of metal ball is more than that of rubber ball |
11 |
| 1141 | A man getting down from a running bus falls forward: A. as the forward movement of bus tries to pull the man forward B. due to inertia of upper part of the body moves in the forward direction while feet come to the rest as soon as they touch the road C. as he leans forward as a matter of habit D. due to the combination effect of all the three factors stated in ( (A),(B) ) and ( (C) ) |
11 |
| 1142 | Galileo’s law of inertia is another name for newton’s (…) law of motion A. First B. second c. Third D. Any one of the above |
11 |
| 1143 | The circumference of a circular track is ( 400 pi / m . ) If the optimum speed with which a vehicle can be driven along it is to be ( 20 m / s ), the angle of banking of the road must be about A ( cdot tan ^{-1}(0.02) ) B. ( tan ^{-1}(0.4) ) c. ( tan ^{-1}(0.8) ) D. ( tan ^{-1}(0.2) ) |
11 |
| 1144 | A large force is acting on a body for a short time. The impulse imparted is equal to the change in : A. Acceleration B. Momentum c. Energy D. Velocity |
11 |
| 1145 | A chain is held on friction-less horizontal table with one-fourth of its length hanging over the edge. If the chain gas a length I and a mass ( mathrm{M} ) what is the work required to pull the hanging part back on the table? |
11 |
| 1146 | Kumaran went to a shop near his house on a bicycle. The bicycle made a lot of noise when he pedalled it. After coming home, he applied some oil on some parts of the bicycle. Then there was no noise, why? | 11 |
| 1147 | topp Q Type your question stationary by applying a force P paralle to the plane. The direction of force pointing up the plane is taken to be positive. As P is varied from ( boldsymbol{P}_{1}= ) ( m g(sin theta-mu cos theta) ) to ( P_{2}=m g(sin theta+ ) ( mu cos theta), ) the frictional force f versus ( P ) graph will look like |
11 |
| 1148 | TUU UI wese blocks A and B are moving towards each other with ccelerations a and b as shown in Fig. 6.310, find the net 21. If the blocks A acceleration of block C. Fig. 6.310 b. – (a+b) a. ai – 2(a + b); c. ai – (a + b) i d. None of these |
11 |
| 1149 | A ( 20 mathrm{kg} ) metal block is place on a horizontal surface. The block just begins to slide when horizontal force of ( 100 mathrm{N} ) is applied to it. Calculate the coefficient of static friction. A . 78.4 B. 100 N ( c cdot 84 mathrm{N} ) D. 9.5 N |
11 |
| 1150 | A uniform rod of mass ( 1 mathrm{kg} ) is hanging from a thread attached at the midpoint of the rod. A block of mass ( m=3 mathrm{kg} ) hangs at the left end of the rod and block of mass ( M ) hangs at the right side at ( 80 mathrm{cm} ) from block ( m . ) If system is in equilibrium. Calculate ( M ) ( A cdot 4 ) kg в. 5 кв ( c cdot 6 mathrm{kg} ) ( D cdot 8 mathrm{kg} ) E. 9 kg |
11 |
| 1151 | Differentiate between mass and weight. | 11 |
| 1152 | A large truck and a car, both moving with a velocity of magnitude ( v ), have a head-on collision. If the collision lasts for ( 1 s ) which vehicle experiences greater force of impact? ( mathbf{A} cdot ) Truck B. Car c. Both experience equal and opposite force D. Data insufficient |
11 |
| 1153 | 19. The value of acceleration a, at the moment spring TU is cut is a. g/5, upwards b. g/5, downwards c. g/3, upwards d. Zero |
11 |
| 1154 | A ware house worker exerts a constant horizontal force of magnitude ( 85 N ) on a ( 40 k g ) box that is initally at rest on the floor of the ware house. After moving a distance of ( 2 m ) the speed of the box is ( 1 m s^{-1} . ) The coefficent of friction between the box and the ware house floor is ( left(boldsymbol{g}=mathbf{1 0 m} boldsymbol{s}^{-mathbf{2}}right) ) A ( .5 / 16 ) в. ( 3 / 16 ) c. ( 19 / 80 ) D. ( 0.25 / 16 ) |
11 |
| 1155 | 14. A bob of mass M is suspended by a massless sur length L. The horizontal velocity V at position A is just sufficient to make it reach the point B. The angle o at which the speed of the bob is half of that at A satisfies Fig. 8.310 (IIT JEE, 2008) a. 0 = c. 7 <0 < 37 3r cosa ANU |
11 |
| 1156 | A block of mass ( 0.2 mathrm{kg} ) is suspended from the ceiling by a light string. ( mathbf{A} ) second block of mass ( 0.3 mathrm{kg} ) is suspended from the first block through another string. Find the tensions in the two strings. Take ( g=10 m / s^{2} ) |
11 |
| 1157 | A motor cyclist rides around the well with a round vertical wall and does not fall down while riding because: A. the force of gravity disappears B. he loses weight some how c. he is kept in this path due to the force exerted by surrounding air D. the frictional force of the wall balances his weight |
11 |
| 1158 | A box is being lifted by a fork-lift truck. The weight o fthe box is ( 3000 N ). The force exerted by the fork-lift truck on the box is ( 3500 N ) vertically upwards. What is the resultant vertical force on the box? fork A. ( 500 N ) downwards B. ( 500 N ) upwards c. ( 6500 N ) downwards D. ( 6500 N ) upwards |
11 |
| 1159 | Mass( times )velocity( = ) A. Impulse B. Momentum c. Area D. Force |
11 |
| 1160 | A ( 7 k g ) object is accelerating to the right at ( 2 k m / s ).what is the rightward net force acting on it? A . ( 1400 N ) в. ( 2000 N ) c. ( 670 N ) D. ( 890 N ) |
11 |
| 1161 | State whether given statement is True or False.
You fall in the forward direction when a |
11 |
| 1162 | A ball of mass ( 100 mathrm{g} ) is moving with a velocity of ( 10 mathrm{m} s^{-1} . ) The force of the blow by the bat acts for 0.01 seconds. What is the force exerted on the ball by the bat if the ball retraces its path with same speed? A. ( 100 mathrm{N} ) B. 200 N c. 300 N D. 400 N |
11 |
| 1163 | The time, in which a force of ( 2 mathrm{N} ) produces a change in momentum of ( 0.4 k g m s^{-1} ) in a body whose mass is 1 kg is: A. ( 0.2 mathrm{s} ) B. 0.02 ( s ) ( c .0 .5 mathrm{s} ) D. ( 0.05 mathrm{s} ) |
11 |
| 1164 | Powder is used in carrom board for: A. Increasing friction B. Decreasing friction c. Decoration D. None of the above |
11 |
| 1165 | TIJU. JSC . m . 1.0 MS 34. A painter of mass M stands on a platform of mass mana pulls himself up by two ropes which hang over pulle as shown in Fig. 6.319. He pulls each rope with force and moves upward with a uniform acceleration a. Find a, neglecting the fact that no one could do this for long time. Fig. 6.319 D a a. 4F+(2M + m), – M+2m 4F-(M + m)g M +m 4F +(M+mg M+2m 4F-(M + m) 2M +m d |
11 |
| 1166 | What is the minimum coefficient of friction for a solid sphere to roll without slipping on an incined plane of inclination ( boldsymbol{theta} ) ? A ( cdot frac{2}{7} tan theta ) B ( cdot frac{1}{3} g tan theta ) c. ( frac{1}{2} tan theta ) D. ( frac{2}{5} tan theta ) |
11 |
| 1167 | Rocket propulsion works on the principle of: A. Newtons laws of motion B. Faradays laws of electromagnetic induction C. Laws of thermodynamics D. Archimedes |
11 |
| 1168 | If the normal reactional force is doubled, the coefficient of friction is : A. doubled B. halved c. not charged D. tripled |
11 |
| 1169 | Two Particles are dropped simultaneously from the top of a tall building. Particle 1 has mass ( M_{1} ) and particle 2 has mass ( M_{2} . ) Find out the ratio of their momentum just before they hit the ground? Neglect the air resistance A ( cdot frac{sqrt{M_{1}}}{M_{2}} ) в. ( frac{M_{1}}{M_{2}} ) ( left(frac{M_{1}}{M_{2}}right)^{2} ) D. 1 E. None of the above |
11 |
| 1170 | The strength of gravity on Mars is only ( 40 % ) of that on earth. If a child has a mass of ( 60 mathrm{kg} ) on earth, what would the child’s weight be on Mars? A . 24 в. 60 N c. ( 240 N ) D. ( 600 N ) E. None of the above is correct within ( 10 % ) |
11 |
| 1171 | A ( 1500 k g ) car is initially moving with speed ( 30 m / s . ) Suddenly, a rock falls onto the road ahead. The maximum coefficient of friction |
11 |
| 1172 | Frictional force in a ceiling fan is reduced by using A. Reduced air resistance B. Ball bearings c. Both (A) and (B) D. None of the above |
11 |
| 1173 | tllustration 7.17 An object of mass 10 kg is to be kept at rest on an inclined plane making an angle of 37° to the horizontal by applying a force F along the plane upwards as shown in Fig. 7.45. The coefficient of static fiction between the object and the plane is 0.2. Find the magnitude of force F. [Take g = 10 ms] 8 = 10 m/s2 -Hs = 0.2 1370 sin 37° = 0.6 cos 37° =0.8 Fig. 7.45 |
11 |
| 1174 | A ball of mass ( m=1 mathrm{kg} ) strikes smooth horizontal floor as shown in figure. The impulse exerted on the floor is A. 6.25 Ns B. 1.76 Ns c. ( 7.8 mathrm{Ns} ) D. 2.2 Ns |
11 |
| 1175 | mas m. The 60. Figure 6.340 shows two blocks, each of mass system is released from rest. If accelerations of bi A and B at any instant (not initially) are a, and respectively, then as and an Fig. 6.340 a. a, = a, cos e c. a, = az b. az = a, cos 0 d. None of these |
11 |
| 1176 | Assertion The Sl unit of weight is newton. Reason Weight is the force of gravity with which a body is attracted towards the earth. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
11 |
| 1177 | If earth attracts an apple with a force of 10 newton, then with what force the apple will attract the earth. |
11 |
| 1178 | An inset crawls up a hemispherical surface very slowly. The coefficient of friction between the insect and the surface is ( 1 / 3 . ) If the line joining the center of the hemispherical surface to the insect makes an angle ( alpha ) with the vertical, the maximum possible value of ( alpha ) is given by ( mathbf{A} cdot cot alpha=3 ) ( mathbf{B} cdot tan alpha=3 ) ( mathbf{c} cdot sec alpha=3 ) D. ( operatorname{cosec} alpha=3 ) |
11 |
| 1179 | A turn of radius ( 20 mathrm{m} ) is banked for the vehicles going at a speed of ( 36 k m / h ). If the coefficient of static friction between the road and the tyre is ( 0.4 . ) What are the possible speeds of a vehicle so that it neither slips down nor skids up? ( left(g=9.8 m / s^{2}right) ) A ( cdot 2.2 m s^{-1} leq v leq 4.2 m s^{-1} ) B. ( 4.2 m s^{-1} leq v leq 15 m s^{-1} ) c. ( 15 m s^{-1} leq v leq 18.5 m s^{-1} ) D. ( 15 mathrm{ms}^{-1} leq v leq 22.5 mathrm{ms}^{-1} ) |
11 |
| 1180 | Two beads of masses ( m_{1} ) and ( m_{2} ) are threaded on a smooth circular wire of radius’ ( a^{prime} ) fixed in a vertical plane. ( B ) is stationary at the lowest point when ( boldsymbol{A} ) is gently dislodged from rest at the highest point. ( A ) collides with ( B ) at the lowest point. The impulse given to ( boldsymbol{B} ) due to collision is just great enough to carry it to the level of the centre of the circle while ( A ) is immediately brought to rest by the impact. Find ( boldsymbol{m}_{1}: boldsymbol{m}_{2} ) |
11 |
| 1181 | When a bicycle travels on a rough surface, its speed, A. increases B. decreases c. remains the same D. none of these |
11 |
| 1182 | The action and reaction forces referred to in Newton’s third law of motion A. must act on same body B. must act on different bodies c. need not be equal in magnitude but must have the same line of action D. must be equal in magnitude but need not have the same line of action |
11 |
| 1183 | State whether True or False: A man slip when he steps on a banana peel thrown on the road. |
11 |
| 1184 | Force produced by shooting makes the bullet to move forwards, also equal force in opposite direction is applied which recoils gun backwards. It is used to refill gun in semi automatic weapons. State True or False. |
11 |
| 1185 | The substance that helps to friction are called lubricants. A. increase B. decrease c. create D. eliminate |
11 |
| 1186 | Four children were asked to arrange forces due to rolling, static and sliding frictions in a decreasing order. Their arrangements are given below. Choose the correct arrangement in descending order: A. rolling, static, sliding B. rolling, sliding, static c. static, sliding, rolling D. sliding, static, rolling |
11 |
| 1187 | With increase of temperature, the frictional force acting between two surfaces increases. A. True B. False c. Ambiguous D. Data Insufficient |
11 |
| 1188 | Why is friction greater between rough surfaces than between smooth ones? | 11 |
| 1189 | A ball of mass ( 50 mathrm{g} ) is dropped from a height ( h=10 mathrm{m} . ) It rebounds losing 75 percent of its total mechanical energy. If it remains in contact with the ground for ( triangle boldsymbol{t}=mathbf{0 . 0 1} ) sec, find the impulse of the impact force. |
11 |
| 1190 | Hailstones falling from atmosphere relates to: A. static friction B. rolling friction c. sliding friction D. fluid friction |
11 |
| 1191 | Wheel reduce friction due to. A. more area of contact B. less area of contact ( c cdot operatorname{size} ) D. all of the above |
11 |
| 1192 | A ball of mass ‘m’ moves normal to a wall with a velocity ‘u’ and rebounds with a velocity ‘v’. The change in momentum of the ball is (surface of the wall is smooth): A. ( m(u+v) ) towards the wall B. ( m(u-v) ) towards the wall c. ( m(u+v) ) away from the wall D. ( m(u-v) ) away from the wall |
11 |
| 1193 | Which law of Newton defines an ‘inertial frame of reference’? A. First law of motion B. Second law of motion c. Third law of motion D. Law of gravitation |
11 |
| 1194 | A cricket ball of mass 120 g is moving with a velocity of ( 12 mathrm{m} s^{-1} . ) It turns back and moves with a velocity of ( 20 mathrm{m} s^{-1} ) when hit by a bat. Find the impulse if the force acts on the ball for 0.02 s. A ( cdot 4 ) N B. 8 N s c. 32 N ( s ) D. 192 N s |
11 |
| 1195 | A boat is streamlined to reduce the resistance to motion offered by water A. True B. False |
11 |
| 1196 | To keep a body moving with constant velocity on a frictionless surface, an external force: A. should act continuously B. should be a variable force c. is not required D. should act opposite to the direction of motion |
11 |
| 1197 | Water sprinkler used for grass lawns begins to rotate as soon as the water is supplied. It is based on which law? A. Newton’s first law of motion B. Newton’s second law of motion c. Newton’s third law of motion D. First law of thermodynamics |
11 |
| 1198 | 6. A plumb bob is hung from the ceiling of a train compartment. The train moves on an inclined track of inclination 30° with horizontal. The acceleration of train up the plane is a=g/2. The angle which the string supporting the bob makes with normal to the ceiling in equilibrium is a. 30° b. tan-|(2113) c. tan-‘(73/2) d. tan- (2) |
11 |
| 1199 | A ( 6 k g ) block is kept over a rough surface with coefficients of friction ( mu_{s}= ) 0.6 and ( mu_{4}=0.4 ) as shown in figure. time varying force ( boldsymbol{F}=mathbf{4} boldsymbol{t}(boldsymbol{F} ) in newton and ( t ) in ( operatorname{second} ) ) is applied on the block as shown. Plot a graph between acceleration of block and time. (Take [ begin{array}{c} left.boldsymbol{g}=mathbf{1 0 m} / boldsymbol{s}^{2}right) \ boldsymbol{6} mathbf{k g} quad boldsymbol{6} mathbf{k g} \ boldsymbol{mu}_{mathbf{5}}=mathbf{0 . 6} \ boldsymbol{mu}_{mathbf{k}}=mathbf{0 . 4} end{array} ] |
11 |
| 1200 | Which of the following activity would not be possible in the absence of friciton? A. holding a glass B. writing on a paper c. sitting on a chair D. all of the above |
11 |
| 1201 | Two identical ladders, each of mass ( mathrm{M} ) and length I are resting on a rough horizontal surface as shown in Fig. block of mass ( mathrm{m} ) hangs from P. If the system is in equilibrium, find the magnitude and the direction of frictional force at ( A ) and ( B ) |
11 |
| 1202 | Why is it advised to tie any luggage kept on the roof of a bus with a rope? | 11 |
| 1203 | A hammer weighing ( 3 mathrm{kg}, ) moving with a velocity of ( 10 mathrm{m} / mathrm{s}, ) strikes against the head of a spike and drives it into a block of wood. If the hammer comes to rest in ( 0.025 s, ) the impulse associated with the ball will be A. 30 N s B. -30 N s c. ( 15 mathrm{N} ) s D. -15 N s |
11 |
| 1204 | A ( 70 mathrm{kg} ) astronaut in a ( 110 mathrm{kg} ) MMU experiences an acceleration of 0.029 ( mathrm{ms}^{-2} ) when he fires one of the MMU’s thrusters, if the speed of escaping ( N_{2} ) gas is ( 490 mathrm{ms}^{-1} ), how much amount of gas is used in 5 s. A. ( 5.53 g ) в. ( 5.53 k g ) c. ( 555.3 g ) D. ( 55.3 g ) |
11 |
| 1205 | A cricket ball of mass ( 150 g ) moving with a speed of ( 126 k m / h ) hits at the middle of the bat, held firmly at its position by the batsman. The ball moves straight back to the bowler after hitting the bat. Assuming that collision between ball and bat is completely elastic and the two remain in constant for ( 0.001 s, ) the force that the batsman had to apply to hold the bat firmly at its place would be: A . ( 10.5 N ) B. ( 21 N ) c. ( 1.05 times 10^{4} N ) D. ( 2.1 times 10^{4} N ) |
11 |
| 1206 | Three weight ( W, 2 W ) and ( 3 W, ) are connected to identical springs suspended from rigid horizontal rod. The assembly of the rod and the weights fall freely. The positions of the weights from the rod are such that A. ( 3 W ) will be farthest B. ( W ) will be farthest c. all will be at the same distance D. ( 2 W ) will be farthest |
11 |
| 1207 | A horse continues to apply a force in order to move a cart with a constant speed. This is because: A. the force applied by the horse balances the gravitational force. B. the force applied by the horse balances the force of friction c. Horse does not apply any force D. None of these |
11 |
| 1208 | Blocks P and R starts from rest and moves to the right with acceleration ( a P=12 t a P=12 t . ) Here ( f ) is in seconds. The time when block ( Q ) again comes to rest is? ( A cdot 1 ) в. ( frac{3}{2} s ) ( c .2 s ) D. ( frac{1}{4} s ) |
11 |
| 1209 | Suppose the entire system of the previous question is kept inside an elevator which is coming down with an acceleration ( a<g ). Repeat parts (a) and (b). |
11 |
| 1210 | A car and a lorry are moving with same momentum, if same braking force is applied, then : A. Car comes to rest in shorter distance B. Lorry comes to rest in shorter distance c. Both travels same distance before coming to rest. D. None |
11 |
| 1211 | Which of the following statements is not true? A. The coefficient of friction between two surfaces increases as the surface in contact are made rough B. The force of static friction acts in a direction opposite to the applied force C. Rolling friction is greater than sliding friction D. The coefficient of friction between wood and wood is less than 1 |
11 |
| 1212 | The time at which block will leave the inclined plane is? A . 1 s B . 2 s ( c cdot 3 s ) D. 4 s |
11 |
| 1213 | The force of friction is normal reaction between the surfaces. A. Inversely propotional to B. directly propotional to c. propotional to the square of D. independent of |
11 |
| 1214 | A block of mass ( M_{1}=10 mathrm{kg} ) is placed on a slab of mass ( M_{2}=30 mathrm{Kg} ). The slab lies on a frictionless horizontal surface as shown in figure. The coefficient of static friction between the block and slab is ( mu_{s}=0.25 ) and that of dynamic friction is ( mu_{k}=0.12 . ) A force ( F=40 mathrm{N} ) acts on block ( M_{1} ). The acceleration of the slab will be ( left(g=10 mathrm{m} / mathrm{s}^{2}right) ) A ( cdot 0.5 mathrm{m} / mathrm{s}^{2} ) B. ( 0.4 mathrm{m} / mathrm{s}^{2} ) ( mathrm{c} cdot 1 mathrm{m} / mathrm{s}^{2} ) D. ( frac{5}{6} m / s^{2} ) |
11 |
| 1215 | A block is moving on an inclined plane making an angle ( 45^{circ} ) with the horizontal and the coefficient of friction is ( mu . ) The force required to just push it up the inclined plane is 3 times the force required to just prevent it from sliding down. If we define ( N=10 mu, ) then ( N ) is ( A cdot 2 ) B. 3 ( c cdot 4 ) D. 5 |
11 |
| 1216 | What is the force acting on the connecting bar? A . ( 150 mathrm{N} ) B. 100 N ( c .75 mathrm{N} ) D. 125 N |
11 |
| 1217 | topp Q Type your question from rest for each situation represented by the graphs, during which situation was the cart moving fastest after 8 seconds? 4 B ( c ) ( D ) |
11 |
| 1218 | Keeping the angle of banking same, if the radius of curvature is made four times, the percentage increase in the maximum speed with which a vehicle can travel on a circular road is: A . 25% B. 50% c. 75% D. 100% |
11 |
| 1219 | A weight ‘ ( W ) ‘ can be just supported on a rough horizontal plane by a force ‘ ( boldsymbol{F} ) ‘ either acting along the plane or horizontally. If ( theta ) is the angle of friction, then ( frac{boldsymbol{F}}{W} ) is A ( cdot tan theta ) B. ( sec theta ) ( c cdot sin theta ) ( D cdot cos theta ) |
11 |
| 1220 | In which case does the normal force act between the object and table? ( mathbf{A} cdot ) Both ( A ) and ( B ) B. Only ( A ) C. Only ( B ) D. None of these |
11 |
| 1221 | A man is stranded in the middle of a perfectly smooth island of ice, where there is no friction between the ground and his feet. Under these circumstances, A. he can reach the desired corner by throwing any object in the same direction B. he can reach the desired corner by throwing any object in the opposite direction C. he has no chance of reaching any corner of the island D. he can reach the desired corner by walking on the ground in that direction |
11 |
| 1222 | Two bodies ( A ) and ( B ) of same mass are moving with velocities ( boldsymbol{v} ) and ( 2 boldsymbol{v} ) respectively. What is the ratio of their momentum? A . 3: 2 B. 2: c. 1: 2 D. 1: |
11 |
| 1223 | The vertical height of an almirah is ( 2 m ) its base is a square of side length ( 0.4 m ) and its mass is ( 200 k g . ) The maximum height from the floor at which a horizontal force ( 490 N ) should be applied on the almirah so that it does not tilt is: A. ( 0.6 m ) в. ( 0.8 m ) ( c .1 m ) D. ( 1.2 m ) |
11 |
| 1224 | 11. Four blocks are arranged on a smooth horizontal surface as shown in Fig. 7.249. The masses of the blocks are given (see the figure). The coefficient of static friction between the top and the bottom blocks is Mr. What is the maximum value of the hori- zontal force F, applied to one of the bottom blocks as shown, that makes all four blocks move with the same Fig. 7.249 acceleration? |
11 |
| 1225 | 5. Blocks A and B in the Fig. 7.262 are connected by a bar of negligible weight. Mass of each block is 170 kg and HA = 0.2 and Hp = 0.4, where HA and Up are the coefficients of limiting friction between blocks and plane, calculate the force developed in the bar (8= 15 m 10 ms?) Fig. 7.262 a. 150 N b. 75 N c. 200 N d. 250 N |
11 |
| 1226 | Powder is a lubricant A. True B. False c. None D. Can’t say |
11 |
| 1227 | Eleven forces each equal to ( 5 N ) act on a particle simultaneously. If each force makes an angle ( 30^{circ} ) with the next one, the resultant of all forces is В. 55 N ( c .5 N ) D. zero |
11 |
| 1228 | One of the rectangular components of a force of ( 50 mathrm{N} ) is ( 30 mathrm{N} ). The other rectangular component will be : A. ( 40 mathrm{N} ) B. 30 N ( c . ) 35 ( mathrm{N} ) D. 45 N |
11 |
| 1229 | SS Two trolleys 1 and 2 are moving with accelerations a, and respectively, in the same direction. A block of mace trolley 1 is in equilibrium from the frame of observer stationary with respect to trolley 2. The magnitude of friction force on block due to trolley is (assume that no horizontal force other than friction force is acting on block). 02 Observer a. m(a – a) c. mai Fig. 6.344 b. ma2 d. Data insufficient |
11 |
| 1230 | The time, in which a force of ( 2 mathrm{N} ) produces a change as momentum of 0.4 kg ( m s^{-1} ) in the body is : A. ( 0.2 s ) B. 0.02s c. ( 0.5 mathrm{s} ) D. 0.05s |
11 |
| 1231 | The surface of a table is smoother as compared to that of a road. This is due to: A. irregularities in the surface of road B. polishing of the table c. a road surface may have more dust as compared to table D. all of the above |
11 |
| 1232 | A parrot is sitting on the floor of a wire cage which is being carried by a boy, starts flying. The boy will feel that the box is now A. heavier B. lighter C. shows no change in weight D. lighter in the beginning and heavier later |
11 |
| 1233 | Illustration 7.45 A car of mass m moving over a concave bridge of radius r. Find the normal reaction acting on car when it is at the lowest point of the bridge. |
11 |
| 1234 | ( A 20 mathrm{kg} ) block is in motion on a rough horizontal surface. A horizontal force of ( 60 mathrm{N} ) is required to keep the body moving with constant speed. Then find coefficient of kinetic friction? ( (mathrm{g}=10 mathrm{m} ) ( left.s^{-2}right) ) A. 0.4 B. 0.3 ( c cdot 0.8 ) D. 0.6 |
11 |
| 1235 | Which of the following groups of forces could be in equilibrium? A. ( 3 N, 4 N, 5 N ) в. ( 4 N, 5 N, 10 N ) c. ( 30 N, 40 N, 80 N ) D. ( 1 N, 3 N, 5 N ) |
11 |
| 1236 | A car driven round curved path of radius ( 18 m ) without the danger of skidding. The coefficient of friction between the tyres of the car and the surface of the curved path is ( 0.5 . ) What is the maximum speed in kmph of the car for safe driving nearly? ( left(boldsymbol{g}=mathbf{1 0 m} boldsymbol{s}^{-mathbf{2}}right) ) A . 9.3 B. 34.48 c. 18.42 D. 20.15 |
11 |
| 1237 | Which of the following statement is CORRECT? A. Word done by static friction is always zero B. Work done by kinetic friction is always negative C. The negative of the work done by the conservative internal forces on a system equals the change in kinetic energy D. The work done by all the forces on a system equal to change in kinetic energy |
11 |
| 1238 | A body of mass ( 2 k g ) collides with a wall with a speed of ( 100 mathrm{ms}^{-1} ) are rebounds with the same speed. If the time of contact is ( 1 / 50 s, ) the force exerted on the wall is ( A cdot 8 N ) B . ( 2 times 10^{4} N ) c. ( 4 N ) D. ( 10^{4} N ) |
11 |
| 1239 | A turn of radius ( 20 m ) is banked for the vehicles going at a speed of ( 36 k m / h . ) If the coefficient of static friction between the road and the tyre is ( 0.4, ) what are the possible speeds of a vehicle so that it neither slips down nor skids up? A ( .14 .7 mathrm{km} / mathrm{h} ) and ( 54 mathrm{km} / mathrm{h} ) B. ( 14.2 mathrm{km} / mathrm{h} ) and ( 50 mathrm{km} ) c. ( 11.7 k m / h ) and ( 44 mathrm{km} / mathrm{h} ) D. ( 17.7 mathrm{km} / mathrm{h} ) and ( 34 mathrm{km} / mathrm{h} ) |
11 |
| 1240 | 15. What is the acceleration of block B? a. 30/77 m’s-2 b. 60/77 ms-2 c. 80/77 ms-2 d. 120/77 m2 |
11 |
| 1241 | A ( 3 m ) long ladder weighing 20 kg leans on a frictionless wall. Its feet rest on the floor ( 1 mathrm{m} ) from the wall as shown in Fig. Find the reaction forces of the wall and the floor |
11 |
| 1242 | A ball moving with a speed of ( 30 mathrm{m} / mathrm{s} ) hits the wall and bounces back with same speed. The contact time between the ball and the wall is 0.1 s. Calculate the force exerted by the wall on the ball if mass of the ball is 0.25kg. A. on B. – 100N c. – 300N D. – 150N E. ( 100 N ) |
11 |
| 1243 | 1. When a person walks on a rough surface, the frictional force exerted by the surface on the person is opposite to the direction of his motion. (IIT JEE, 1981) |
11 |
| 1244 | The figure shows the position -time ( left(x^{-}right. ) t) graph of one-dimensional motion of a body of mass 0.4 kg. The magnitude of each impulse is : ( mathbf{t}(mathrm{s}) ) A . ( 0.4 mathrm{Ns} ) B. 0.8 Ns c. 1.6 Ns D. 0.2 Ns |
11 |
| 1245 | The pully of the system shown in Fig. is massless and frictionless and thread is inextensible. The horizontal surface over which block ( mathrm{C} ) is placed is smooth while coefficient for all the remaining surfaces is ( mu ) Calculate minimum accleration a with |
11 |
| 1246 | Action and reaction force acts on: A. same body B. different bodies c. lower body D. upper body |
11 |
| 1247 | on wow ( F ) |
11 |
| 1248 | Statement I : When a clay ball of mass ( mathrm{m} ) hits normally a wall with speed v and sticks to it, impulse imparted to the ball is 2 mv. Statement II: Impulse is equal to rate of change of linear momentum with time. |
11 |
| 1249 | In the situation shown in figure, a wedge of mass ( m ) is placed on a rough surface, on which a block of equal mass is placed on the inclined plane of wedge The friction coefficient between the wedge and the block and also between the ground and the wedge is ( mu . A n ) external force ( F ) is applied horizontally on the wedge towards the right, assuming block does not slide on the wedge. Find the minimum value of Force ( F ) at which the block will start slipping. |
11 |
| 1250 | is a self adjusting force. | 11 |
| 1251 | While opening a tap with two fingers, the forces applied are : A. Equal in magnitude B. Parallel to each other c. opposite in direction D. All the above |
11 |
| 1252 | Assertion Walking is more easier on the ground than on sand. Reason In the former case reaction comes into play more quickly. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
11 |
| 1253 | State whether the given statement is true or false : A horse continues to apply a force in |
11 |
| 1254 | What is the value of ( p_{1} ) and ( m_{2} ? ) ( begin{array}{lll}mathrm{m}(mathrm{kg}) & mathrm{v}(mathrm{m} / mathrm{s}) & mathrm{p}=mathrm{mv}(mathrm{kgm} / mathrm{s}) \ 85 & 60 & p_{1} \ m_{2} & 2.5 & 6.25end{array} ) ( A cdot 5100,2.5 ) B. 5.1 , 2.5 c. 2500, D. 55, 2.6 |
11 |
| 1255 | A car drives along straight level frictionless road by an engine delivering constant power. Then velocity is directly proportional to? ( A cdot t ) B. ( frac{1}{sqrt{t}} ) ( c cdot sqrt{t} ) D. None of these |
11 |
| 1256 | The friction coefficient between the table and the block shown in the figure is 0.2 . Find the tensions in the two strings. |
11 |
| 1257 | 4. A horizontal force just sufficient to move a body of mass 4 kg lying on a rough horizontal surface is applied on it. The coefficient of static and kinetic friction between the body and the surface are 0.8 and 0.6, respectively. If the force continues to act even after the block has started moving, the acceleration of the block in ms-is (g = 10 ms) a. 1/4 b. 1/2 c. 2 d. 4 |
11 |
| 1258 | A turn of radius ( 20 mathrm{m} ) is banked for the vehicles going at a speed of ( 36 k m h^{-1} ) If the coefficient of static friction between the road and the tyre is 0.4 what are the possible speed of a vehicle so that it neither slips down nor skids up? |
11 |
| 1259 | A circular racetrack of radius ( 300 m ) is banked at an angle of ( 15^{circ} . ) If the coefficient of friction between the wheels of a race car and the road is 0.2 (a) What is the optimum speed of the race car to avoid wear and tear on its tires? (b) What is the maximum permissible speed to avoid slipping? |
11 |
| 1260 | (assume that B has not yet reached the ground). 8. A smooth pulley A of mass Mois 1) Smooth pulley A of mass M, is lying on a frictionless table. A massless rope passes round the pulley and asses My and My tied to its ends, the two portions of the string being perpendicular to the edge of the table so that the masses hang vertically. Find the acceleration of the pulley. ma Mo to M2 M Fig. 6.288 |
11 |
| 1261 | ( A ) block ( X ) kept on an inclined surface just begins to slide, if the inclination is ( boldsymbol{theta}_{1} . ) The block is replaced by another block ( Y ) and it is found that it just begins to slide, if the inclination ( theta_{2} ) if ( boldsymbol{theta}_{2}>boldsymbol{theta}_{1} ) ). Then A. Mass of ( x= ) mass of ( Y ) B. Mass of ( x ) mass of ( Y ) D. All the above three options are possible |
11 |
| 1262 | A cricket ball of mass 120 g is moving with a velocity of ( 12 m s^{-1} ), it turns back and move with a velocity of ( 20 m s^{-1} ) when hit by a bat. Find the impulse and the force, if the force acts for 0.02 s. |
11 |
| 1263 | Water sprinkler used for grass lawns begins to rotate as soon as the water is supplied. It is based on which law? |
11 |
| 1264 | The net force acting is not zero on A. a retarding train B. a ball falling with terminal velocity C . a kite held stationary D. a truck moving with constant velocity ( mathrm{E} cdot ) a book placed on a table |
11 |
| 1265 | 72. A body is moving in a circle with a speed of 1 ms.This speed increases at a constant rate of 2 ms every second. Assume that the radius of the circle described is 25 m. The total acceleration of the body after 2 s is a. 2 ms 2 b. 25 ms 2 c. 5 ms2 d. ſims? |
11 |
| 1266 | 5. Statement I: In high jump, it hurts less when an athlete lands on a heap of sand. Statement II: Because of greater distance and hence greater time over which the motion of an athlete is stopped, the athlete experiences less force when lands on the heap of sand. |
11 |
| 1267 | A block of mass m rests on a rough inclined plane. The coefficient of friction between the surface and the block if ( mu ) At what angle of inclination ( theta ) of the plane to the horizontal will the block just start to slide down the plane? A ( cdot theta=tan ^{-1} mu ) в. ( theta=cos ^{-1} mu ) c. ( theta=sin ^{-1} mu ) D. ( theta=s e c^{-1} mu ) |
11 |
| 1268 | A wedge of mass ( M=2 mathrm{kg} ) is placed over a rough horizontal surface having coefficient of friction ( mu, ) a block of mass ( m=1 mathrm{kg} ) is placed over this wedge as shown in figure. If coefficient of friction between wedge and block is ( mu_{1}=0.8 ) then the minimum value of ( mu ) so that wedge does not slip over a horizontal surface, is ( A .0 .8 ) в. 0.75 ( c .0 .5 ) D. zero |
11 |
| 1269 | If impulse ( I ) varies with time ( t ) as ( fleft(k g m s^{-1}right)=20 t^{2}-40 t . ) The change in momentum is minimum at ( mathbf{A} cdot t=1 s ) B . ( t=2 s ) c. ( _{t=frac{1}{2} s} ) D. ( t=frac{3}{2} s ) |
11 |
| 1270 | Assertion Newton’s third law of motion is applicable only when bodies are in motion. Reason Newton’s third law applies to all types of forces. e.g. gravitational, electric or magnetic force etc. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
11 |
| 1271 | A stationary ball weighing ( 0.25 k g ) acquires a speed of ( 10 mathrm{m} / mathrm{s} ) when hit by a hockey stick. The impulse imparted to the ball is : A. ( 0.25 mathrm{N} ) s B. 2.5 N s c. ( 2.0 mathrm{N} ) s D. ( 0.5 mathrm{N} ) s |
11 |
| 1272 | Match the following ( begin{array}{llll} & text { List I } & & text { List II } \ & & & \ begin{array}{l}text { Streamlined body } \ text { structure }end{array} & text { a } & begin{array}{l}text { Less no. of } \ text { irregularities }end{array} \ text { 2 } & begin{array}{l}text { objects harder } \ text { againsteach } \ text { other }end{array} & text { b } & text { Lubricant } \ text { 3 } & text { Grease } & text { c } & begin{array}{l}text { Increase } \ text { friction }end{array} \ text { 4 } & text { Smooth surface } & text { d } & begin{array}{l}text { Decrease } \ text { friction }end{array}end{array} ) A . ( 1-d, 2-c, 3-b, 4-a ) ( , 4-b ) B. ( 1-d, 2-c, 3-a ) c. ( 1- ) a, ( 2-d, 3-b, 4-c ) D. 1-a, 2-b, 3-c, 4-d |
11 |
| 1273 | 82. A bead of mass m is released from rest at A to move along the fixed smooth circular track as shown in Fig. 8.260. The ratio of magnitudes of centripetal force and normal reaction by the track on the bead at any point P, described by the angle (0) would Fig. 8.260 a. Increase with O b. Decrease with e c. Remain constant d. First increase with and then decrease f oto bed to |
11 |
| 1274 | A car goes on a horizontal circular road of radius ( R, ) the speed increasing at a constant rate ( frac{boldsymbol{d v}}{boldsymbol{d t}}=boldsymbol{a} . ) The friction coefficient between the road and the tyre is ( mu ). Find the maximum value of speed at which the car is safe to drive. |
11 |
| 1275 | TUMU 13 U TON-MICIllal llallle. Statement I: In Fig. 6.368, ground is smooth and masses both the blocks are different. The net force acting on each of the block is not same. F — в ГА! Smooth Fig. 6.368 Statement II: Acceleration of both will be different. |
11 |
| 1276 | Relation between coefficient of static friction ( mu_{s} ) and angle of friction is B ( cdot mu_{s}=cos theta ) c. ( mu_{s}=tan theta ) D. None of these |
11 |
| 1277 | A ring takes time ( t_{1} ) and ( t_{2} ) for sliding down and rolling down an inclined plane of length ( L ) respectively for reaching the bottom. The ratio of ( t_{1} ) and ( t_{2} ) is A ( cdot sqrt{2}: 1 ) B. ( 1: sqrt{2} ) c. 1: 2 D. 2: 1 |
11 |
| 1278 | The limiting friction between two surfaces does not depend A. on the nature of two surfaces. B. on normal reaction c. on the weight of the body D. on height of the body |
11 |
| 1279 | A dog weighting ( 5 k g ) is standing on a flat boat so that it is ( 10 mathrm{m} ) from the shore. The walks on the boat towards the shore and then halts. The boat weights ( 20 k g ) and one can assume that then no friction between it and the water. How far is the dog from the shore at the end of this time? ( mathbf{A} cdot 3.2 m ) в. ( m ) ( c .10 m ) D. ( 6.8 m ) |
11 |
| 1280 | What is the other name of Galileo’s law of falling bodies? A. Law of motion B. Newton’s first law c. Newton’s second law D. Newton’s third law |
11 |
| 1281 | State whether true or false. A cone resting on its side is an example of a body in neutral equilibrium. A. True B. False |
11 |
| 1282 | Newton’s first law of motion leads to the concept of ( A cdot ) force B. inertia c. both of the above D. temperature |
11 |
| 1283 | A car is traveling is blanked curved road ( operatorname{at} theta=37^{circ} ) of radius ( 125 mathrm{m} ). If the coefficient of friction between the tyres and road is ( mu=0.5 ) and ( g=10 m / s^{2} ) The maximum speed to avoid skidding is. A. ( 50 mathrm{m} / mathrm{s} ) B. 25 ( mathrm{m} / mathrm{s} ) ( c cdot 20 m / s ) D. ( 10 mathrm{m} / mathrm{s} ) |
11 |
| 1284 | A wheel of radius r rolling on a straight line, the velocity of its centre being v. At a certain instant the point of contact of the wheel with the grounds is ( mathrm{M} ) and ( mathrm{N} ) is the highest point on the wheel(diametrically opposite to M). The incorrect statements is? A. The velocity of any point P of the wheel is proportional to MP B. Points of the wheel moving with velocity greater than form a larger area of the wheel than points moving with velocity less than v C. The point of contact M is instantaneously at rest D. The velocities of any two parts of the wheel which are equidistant from centre are equal |
11 |
| 1285 | A particle of mass ( m ) strikes a wall with a velocity ( v ) making an angle ( theta ) with the wall and rebounds.The change in momentum of the particle will be : ( mathbf{A} cdot-2 m bar{v} cos theta ) B. 0 ( mathrm{c} cdot 2 m bar{v} ) D. ( -2 m bar{v} sin theta ) |
11 |
| 1286 | What is fluid friction? | 11 |
| 1287 | 19. A wire, which passes through the hole in a small be bent in the form of quarter of a circle. The wire is fi vertically on ground as shown in the figure. The bea released from near the top of the wire and it slides alo, the wire without friction. As the bead moves from A to R the force it applies on the wire is 90° Fig. 8.313 a. always radially outwards. b. always radially inwards. c. radially outwards initially and radially inwards later. d. radially inwards initially and radially outwards later. (JEE Advanced, 2014) |
11 |
| 1288 | If ( mathrm{KE} ) of a given particle is doubled, its momentum will be: A. Doubled B. Tripled C. Increases by ( sqrt{2} ) times D. Remains unchangedd |
11 |
| 1289 | Assertion Aeroplanes always fly at low altitudes. Reason According to Newton’s third law of motion, for every action there is an equal and opposite reaction. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
11 |
| 1290 | Tllustration 7.52 A hemispherical bowl of radius Ris rotating about its axis of symmetry which is kept vertical. A small ball tent in the bowl rotates with the bowl without slipping on its surface. If the surface of the bowl is smooth and the angle made by the radius through the ball with the vertical is o, find the angular speed at which the bowl is rotating |
11 |
| 1291 | tilustration 6.30 A pulley-rope-mass arrangement is shown in Fig. 6.137. Find the acceleration of block m when the masses are set free to move. Assume that the pulley and the ropes are ideal. Fig. 6.137 Constroint relations Mohod 1. |
11 |
| 1292 | 46. Two identical particles A and B, each of mass m, are interconnected by a spring of stiffness k. If particle B experiences a force F and the elongation of the spring is x, the acceleration of particle B relative to particle A is equal to wwwwwwwww . Fig. 6.329 a. E b. F- kx c. F- 2kx d. kx m m |
11 |
| 1293 | A man is standing on a boat in still water. If he walks towards the shore the boat will: A. move away from the shore B. remain stationary. c. move towards the shore D. sink |
11 |
| 1294 | A particle of mass ( m ) strikes a wall elastically with speed ( v ) at an angle ( 30^{circ} ) with the wall as shown in the figure. The magnitude of impulse imparted to the ball by the wall is: ( A ) в. ( frac{m v}{2} ) ( c cdot 2 m v ) D. ( sqrt{3} ) mv |
11 |
| 1295 | In the figure shown, coefficient or restitution between ( A ) and ( B ) is ( e=frac{1}{2} ) then This question has multiple correct options A cdot velocity of B after collision is ( frac{v}{2} ) B. Impulse between two during collision is ( frac{3}{4} m v ) c. Loss of kinetic energy during the collision is ( frac{3}{16} m v^{2} ) D. Loss of kinetic energy during the collision is ( frac{1}{4} m v^{2} ) |
11 |
| 1296 | A circular racetrack of radius ( 300 m ) is banked at angle of ( 15^{circ} ) If the coefficient of friction between the wheels of a race car and the road is 0.2 what is the ( (a) ) optimum speed of the race car to avoid wear and tear on its tyres and maximum permissible speed to avoid slipping? |
11 |
| 1297 | Two blocks ( A ) and ( B ) of masses ( 5 mathrm{kg} ) and ( 3 mathrm{kg} ) respectively rest on a smooth horizontal surface with ( B ) over ( A ). The coefficient of friction between ( A ) and ( B ) is ( 0.5 . ) The maximum horizontal force (in kg wt.) that can be applied to ( A, ) so that there will be motion of ( A ) and ( B ) without relative slipping, is? A . 1.5 B . 2. ( c cdot 4 ) D. |
11 |
| 1298 | You normally note the speed limits mentioned on highways (on straight roads without turns). Why? A. The road law forces to write the speed limitt B. Its is just a fashion c. on horizontal roads, speed limit has no meaning D. While overtaking one encounters sharp turns |
11 |
| 1299 | ween the man 14. In the above problem, the contact force between the and the crate is a. 2250 N b. 1125 N c. 750 N d. 375 N |
11 |
| 1300 | Two bodies ( A ) and ( B ) having mass ( M ) and ( m ) respectively possesses same kinetic energy. Given that ( boldsymbol{M}>boldsymbol{m} ). If ( boldsymbol{rho}_{boldsymbol{A}} ) and ( rho_{B} ) be their momentum, then which of the following statements is true? ( mathbf{A} cdot rho_{A}=rho_{B} ) В ( cdot rho_{A}>rho_{B} ) c ( cdot rho_{A}<rho_{B} ) D. It cannot be predicted |
11 |
| 1301 | Is force needed to keep a moving body in motion? Which one of the Newton’s laws follow this ? A. No, first law B. Yes, third law c. No, second law D. Yes, first law. |
11 |
| 1302 | The force ‘F’ acting on a particle of mass ( mathrm{m}^{prime} ) is indicated by the force-time graph shown below. The change in momentum of the particle over the time interval from zero to 8 s is A. 24 Ns B. 20 Ns ( c cdot 12 mathrm{Ns} ) ( D cdot 6 mathrm{Ns} ) |
11 |
| 1303 | A force-time graph for a linear motion is shown in figure. The linear momentum gained between oand 6 second is ( A cdot 2 N s ) 3. 4 Ns ( c cdot 6 N s ) D. zero |
11 |
| 1304 | If ( n ) balls hit elastically and normally on a surface per unit area and all units has mass ( mathrm{m} ) and are moving with same velocity u, then force on surface is: A. mun B. 2 mun c. ( frac{1}{2} m u^{2} n ) ( mathbf{D} cdot m u^{2} n ) |
11 |
| 1305 | A ball of mass ( m ) is dropped onto a floor from a certain height. The collision is perfectly elastic and the ball rebounds to the same height and again falls. Find the average force exerted by the ball on the floor during a long time interval. |
11 |
| 1306 | The apparent weight of a body, weighing M kg-wt, during free fall is A. less than Mkg wt B. more than M kg w c. equal to Mkg wt D. zero |
11 |
| 1307 | Consider the following statements: (a) No net force acts on a rain drop falling vertically with a constant speed. (b) If net force acting on the body is zero, momentum of the body remains constant. (c) Particle of different masses falls with different acceleration on earth. (d) It is easier to start motion in a heavier body than a lighter body. Which of the above statements are correct? ( A cdot(b) ) and ( (c) ) B. (a) and (b) c. ( (a),(b) ) and ( (d) ) D. All of the above |
11 |
| 1308 | 2. Statement I: A block of mass m is placed on a smooth inclined plane of inclination with the horizontal. The force exerted by the plane on the block has a magnitude mg cos e Statement II: Normal reaction always acts perpendicular to the contact surface. leie found to be at rent bon |
11 |
| 1309 | 15. A block B is attached to two unstretched springs Si and S2 with spring constants k and 4k, respectively (see Fig. 8.311(a)]. The other ends are attached to identical supports M, and M, not attached to the walls. The springs and supports have negligible mass. There is no friction anywhere. The block B is displaced towards wall 1 by a small distance x [Fig. 8.311(b)] and released. The block returns and moves a maximum distance y towards wall 2. Displacements x and y are measured with respect to the equilibrium position of the block B. The ratio ylx is 2 M₂ MI S2 Si (a) Luin win linin hün 2 M₂ So Fig. 8.311 (IIT JEE, 2008) d. 1 / 2 a. 4 1. 2 c. 1 |
11 |
| 1310 | A machine gun fires a bullet of mass ( 65 g ) with a velocity of ( 1300 m / s ). The man holding it can exert a maximum force of ( 169 N ) on the gun. The number of bullets he can fire per second will be A . 1 B. 2 ( c .3 ) D. 4 |
11 |
| 1311 | Assertion If two objects of different masses have the same momentum, then the lighter body possess greater velocity. Reason For all bodies, momentum always remains the same. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
11 |
| 1312 | Illustration 7.1 A block of weight 100 N lying on a horizontal surface just begins to move when a horizontal force of 25 N acts on it. Determine the coefficient of static friction. |
11 |
| 1313 | The moment ( Pleft(text { in } k g m s^{-1}right) ) of a particle is varying with time ( t ) (in second) as ( boldsymbol{p}=mathbf{2}+mathbf{3} boldsymbol{t}^{2} . ) The force acting on the particle at ( t=3 s ) will be ( A cdot 18 N ) B. 54 ( c cdot 9 N ) D. 15 N |
11 |
| 1314 | A block of mass ( 20 k g ) is pushed with a horizontal force of ( 90 N . ) If the coefficent of static ( & ) kinetic friction are ( 0.4 & 0.3 ) the frictional force acting on the block is A. ( 90 N ) N в. ( 80 N ) ( c cdot 60 N ) D. ( 30 N ) |
11 |
| 1315 | The force applied on a body on a rough surface of coefficient of friction ( mu ) produces an acceleration ( a ). If coefficient of friction between the body and the surface is reduced to ( mu / 3, ) the acceleration increases by 2 units. The value of ( mu ) is: ( mathbf{A} cdot frac{2}{3} g ) B. ( frac{3}{2} g ) ( c cdot frac{3}{g} ) D. ( frac{1}{g} ) |
11 |
| 1316 | State whether the statements are true or false- Frictional force is a non-contact force. |
11 |
| 1317 | A car of mass ( 500 mathrm{kg} ), moving with the velocity of ( 4 mathrm{m} / mathrm{s} ) accelerates uniformly and attains the velocity of ( 8 mathrm{m} / mathrm{s} ) in 10 seconds. Calculate the initial and final momentum of the object. find the magnitude of the force exerted on the car to provide this acceleration. |
11 |
| 1318 | ply. 0.571 4. Regarding the times when the blocks lose contact with ground, which is correct? a. A loses contact at t = 2 s. b. Closes contact at t = 1.5 s. c. A and B lose contact at the same time. d. All three blocks lose contact at the same time. 1 |
11 |
| 1319 | When force ( F ) acts on side of hexagonal body for what range of coefficient of friction will body topple? A ( cdot mu>frac{1}{2 sqrt{3}} ) В. ( _{mu}frac{sqrt{3}}{2} ) D. ( _{mu}<frac{sqrt{3}}{2} ) |
11 |
| 1320 | VU 12. A block of mass mis on an inclined plane of angle 0. The coefficient of friction between the block and the plane is u and tan 0 > u. The block is held stationary by applying a force P parallel to the plane. The direction of force pointing up the Fig. 7.364 plane is taken to be positive. As Pis varied from P, = mg(sin 0-u cos ) to P2 = mg(sin @+ u cos O), the frictional force f versus P graph will look like (IIT-JEE, 2010) P2 P P2 d. |
11 |
| 1321 | Two billiard balls each of mass ( 0.05 k g ) moving in opposite directions with speed ( 6 m s^{-1} ) collide and rebound with the same speed. What is the impulse imparted to each ball due to the other? |
11 |
| 1322 | Automobile tyres have generally irregular projections over their surfaces.Why? | 11 |
| 1323 | Rank the order of the magnitude of the momenta of the four objects pictured below, greatest first. Masses are shown inside the boundaries of the objects. Velocities are shown with the red arrows with the corresponding values. A. Blue and yellow tie, green and purple and orange tie B. Purple and orange tie, blue, yellow, green c. Blue, purple and orange tie, green, yellow D. Green and purple tie, orange, blue and yellow tie E. Green, purple, and orange tie, blue and yellow tie |
11 |
| 1324 | A block of mass ( 1 mathrm{kg} ) and a pan of equal mass are connected by a string going over a smooth light pulley. Initially the system is at rest when a particle of mass ( 1 mathrm{kg} ) falls on the pan and stick to it. If the particle strike the pan with speed ( 6 m / s ) then the speed with which the system moves just after the collision is? A. ( 3 m / s ) в. ( 4 m / s ) c. ( 2.5 m / s ) D. ( 2 m / s ) |
11 |
| 1325 | A block of mass ( 2 mathrm{kg} ) is pushed against a rough vertical wall with a force of ( 40 N ) coefficient of static friction being 0.5 Another horizontal force of ( 15 N ), is applied on the block in a direction parallel to the wall. Will the frictional force exerted by the wall on the block? |
11 |
| 1326 | Inertia means resistance to the change of state. A . True B. False |
11 |
| 1327 | 98. A small sphere is given vertical velocity of magnitude Vo = 5 ms’ and it swings in a vertical plane about the end of a massless string. The angle with the vertical at which string will break, knowing that it can withstand a maximum tension equal to twice the weight of the sphere, is 1= 2 m VO Fig. 8.270 a. cos-12 c. 600 d. 30° |
11 |
| 1328 | Our palms get warmed up when rubbed together. This is because of: A. kinetic energy B. friction c. electrostatic force D. all of the above |
11 |
| 1329 | Two uniform rods of equal length but different masses are rigidly joined to form an L-shaped body, which is then pivoted about 0 as shown in the figure. If the system is in equilibrium in the shown configuration. Then the ratio M/m will be: ( A ) B. ( c cdot sqrt{2} ) D. ( sqrt{3} ) |
11 |
| 1330 | The weight of a freely falling body is always constant. A . True B. False |
11 |
| 1331 | An object is placed on the surface of a smooth inclined plane of inclination ( boldsymbol{theta} ). It takes timer to reach the bottom. If the same object h allowed to slide down a rough inclined plane of inclination ( boldsymbol{theta} ), it takes time ( n t ) to reach the bottom, where ( n ) is a number greater than 1 . The coefficient of friction ( mu ) is given by A ( cdot mu=tan thetaleft(1-frac{1}{n^{2}}right) ) B cdot ( mu=cos thetaleft(1-frac{1}{n^{2}}right) ) c. ( _{mu}=tan theta sqrt{1-frac{1}{n^{2}}} ) D. ( mu=cos theta sqrt{1-frac{1}{n^{2}}} ) |
11 |
| 1332 | Newton’s law of motion were published in the year 1699 A . True B. False |
11 |
| 1333 | MTN2 32. If F2 is removed at this moment, then just after this, the acceleration of my is F2 a. El as b. a + El c. Fra aot m2 – a d. at m2 т, т, |
11 |
| 1334 | A smooth block is released at rest on a ( 45^{circ} ) incline and then slides a distance ( d ) The time taken to slide is ( n ) times as much to slide on rough incline than on a smooth incline. The coefficient of friction is: A в. ( _{mu_{k}}=sqrt{1-frac{1}{n^{2}}} ) c. ( _{mu_{s}=1-frac{1}{n^{2}}} ) D. ( _{mu_{s}}=sqrt{1-frac{1}{n^{2}}} ) |
11 |
| 1335 | The rate of change of linear momentum of a body falling freely under gravity is equal to it’s | 11 |
| 1336 | The system shown is in equilibrium in vertical plane. All the rods and the supports ( A & B ) are light and friction coefficient between supports and horizontal rod is ( mu . ) If maximum value of angle ( alpha ) is ( 37^{0} ) then find the value of ( 4 mu ) Assume light rod exerts force only along the rod. ( A cdot 2 ) B. 3 ( c .5 ) ( D ) |
11 |
| 1337 | 46. If each of the pullies A and B has mass M, then find the net tension force acting on the lower support. Assume pulleys to be frictionless. a. 2Mg b. 6Mg c. 3Mg d. 4Mg |
11 |
| 1338 | The weight of body can be zero. True or false. A . True B. False |
11 |
| 1339 | A body of weight ( 20 mathrm{N} ) is on a horizontal surface, minimum force applied to pull it when applied force makes an angle ( 60^{0} ) with horizontal (angle of friction a ( = ) ( mathbf{3 0}^{0} ) ) is: A. 20 N B. ( 20 sqrt{3} ) N c. ( frac{20}{sqrt{3}} mathrm{N} ) D. zero |
11 |
| 1340 | An intense stream of water of cross sectional area A strikes a wall at an angle ( theta ) with the normal to the wall and returns back elastically. If the density of water is ( rho ) and its velocity is ( v ), then the force exerted on the wall will be : A. ( 2 A v rho cos theta ) B. ( 2 A v^{2} rho cos theta ) c. ( 2 A v^{2} rho ) D. 2Av |
11 |
| 1341 | A particle of mass ( m ) describes a circle of radius ( r . ) The centripetal acceleration of the particle is ( frac{4}{r^{2}} . ) Then the momentum of the particle is A ( cdot_{2} frac{m}{r} ) в. ( 2 frac{m}{sqrt{r}} ) c. ( 4 frac{m}{sqrt{r}} ) D. None of these |
11 |
| 1342 | Write the approximate weight of a body of mass ( 5 k g ? ) B. ( 5 N ) c. ( 0.5 N ) D. ( 50000 N ) |
11 |
| 1343 | A force ( F ) is acting on an object of mass ( m ) to give it an acceleration of ( a ). If ( m ) is doubled and ( F ) becomes 16 th times, what happens to ( a ) ? A. It is divided by eight B. It is divided by two c. It remains unchanged D. It is multiplied by two E. It is multiplied by eight |
11 |
| 1344 | 3. In the arrangement shown in Fig. 7.358, the ends P and Q of an unstretchable string move downwards with uniform speed U. Pulleys A and B are fixed Mass M moves upwards Pl, M ufe with a speed (IIT JEE, 1982) Fig. 7.358 a. 2U cos e c. 2U/cos e b. Ulcos e d. Ucos e |
11 |
| 1345 | A plank of mass ( m_{1} ) with a bar of mass ( m_{2} ) placed on it lies on a smooth horizontal plane. A horizontal force growing with time ( t ) as ( boldsymbol{F}=boldsymbol{a t}(boldsymbol{a} ) is constant) is applied to the bar. Find how the accelerations of the plank ( w_{1} ) and of the bar ( w_{2} ) depend on ( t, ) if the coefficient of friction between the plank and the bar is equal to ( k ) |
11 |
| 1346 | Displacement of a particle of mass ( 2 k g ) moving in a straight line varies with time at ( s=left(2 t^{3}+2right) m . ) Impulse of the force acting on the particle over a time interval between ( t=0 ) and ( t=1 s ) in A. ( 10 N-s ) В. ( 12 mathrm{N}-mathrm{s} ) c. ( 8 N-s ) D. ( 6 N-s ) |
11 |
| 1347 | 5 bullets, each of mass 10 gm are fired per second, vertically upwards, such that a plate of mass 200 gm floats in air. If the bullets rebound with the same velocity back vertically downwards, the velocity with which each bullet is fired in ( mathrm{ms}^{-1} ) is: (Take ( left.g=10 m s^{-2}right) ) A . 10 B. 30 c. 20 D. 40 |
11 |
| 1348 | A heavy block of length ( b ) and height ( h ) is placed at rest on a rough inclined plane of inclination ( theta ) with the horizontal, as shown in figure. (a) The normal reaction from the surface cannot pass through the centre mass.Why? (b) If ( mu ) is the coefficient of friction between the block and the inclined plane, then discuss the conditions of translational and rational equilibrium of the block. A heavy block is placed at rest on a rough inclined plane. |
11 |
| 1349 | A boy of mass ( 40 mathrm{kg} ) is climbing a vertical pole at a constant speed. If the coefficient of friction between his palms and the pole is 0.8 and ( g=10 m s^{-2} ) the horizontal force that he is applying on the pole is: A. 300 N B. 400 N c. ( 500 mathrm{N} ) D. 600 N |
11 |
| 1350 | A disc is freely rotating with an angular speed co on a smooth horizontal plane. It is hooked at a rigid peg ( P ) and rotates about P without bouncing. Its angular speed after the impact will be equal to: ( A ) ( B cdot frac{omega}{3} ) ( c cdot frac{w}{2} ) D. None of these |
11 |
| 1351 | The friction coefficient between a road and the tyre of a vehicle is ( 4 / 3 . ) Find the maximum incline the road may have so that once hard brakes are applied and the wheel starts skidding, the vehicle going down at a speed of ( 36 k m / h r ) is stopped within ( 5 m ) |
11 |
| 1352 | A force of ( 16 mathrm{N} ) is applied on a block of mass ( 4 mathrm{kg} ) with ( mu=0.6 ) Then the force of friction acting on the block is ( 4 K ) newton Find the value of ( K ) [ mu=.6-sqrt{4 k g} mid rightarrow F=16 mathrm{N} ] ( A cdot 4 ) B. 3 ( c cdot 6 ) ( D ) |
11 |
| 1353 | A ball of mass ( 5 ~ K g ) strikes against wall at an angle of ( 45^{circ} ) and is reflected at the same angle. Find the change in momentum |
11 |
| 1354 | According to Newton’s third law, for every action there is: A. an equal and opposite reaction B. an equal force pointing in the same direction c. an unbalanced force D. a reaction that is twice the magnitude E . an unequal and unbalanced force |
11 |
| 1355 | A car moves at a constant speed on a road as sown in figure. The normal force by the road on the car is NA and NB when it is at the points ( A ) and ( B ) respectively. ( mathbf{A} cdot N_{A}=N_{B} ) B. ( N_{A}>N_{B} ) ( mathbf{c} cdot N_{A}<N_{B} ) D. Insufficient information to decide the relation of ( N_{A} ) and ( N_{B} ) |
11 |
| 1356 | An aircraft executes a horizontal loop at a speed of ( 720 mathrm{km} / mathrm{h} ) with its wings banked at ( 15^{0} . ) What is the radius of the loop? |
11 |
| 1357 | What is the value of friction force f for the following value of applied force ( mathrm{F} ) ? a. ( 1 mathrm{N} ) b. ( 2 mathrm{N} ) c. ( 3 mathrm{N} ) d. ( 4 mathrm{N} ) e. ( 20 mathrm{N} ) Assume the coefficient of friction to be [ boldsymbol{mu}_{s}=mathbf{0 . 3}: boldsymbol{mu}_{boldsymbol{k}}=mathbf{0 . 2 5} ] Mass of the body is ( mathrm{M}=1 mathrm{kg} ). (Assume [ begin{array}{l} boldsymbol{g}=mathbf{1 0 m} boldsymbol{s}^{-2} mathbf{)} \ qquad begin{array}{l} sqrt{w}+r \ end{array} end{array} ] |
11 |
| 1358 | A person pushing a wall hard is liable to fall back. Which law is related for this? A. Newton’s first law B. Newton’s second law c. Newton’s third law D. Newton’s gravitational law |
11 |
| 1359 | Which of the following is the most significant law of motion given by Newton? A. First law of motion B. Second law of motion c. Third law of motion D. Zeroth law of motion |
11 |
| 1360 | 10. In the arrangement shown in Fig. 6.290, pulleys D and E are small and frictionless. They do not rotate but threads slip over them without friction and their masses being 4 kg and 11.25 kg, respectively, while the masses of blocks A, B, and C are 2m, m and m’, respectively. When the system is released from rest, downward accelerations of blocks B and C relative to A are found 2mm m’ to be 5 ms – and 3 ms?, respectively. Fig. 6.290 Calculate: a. Acceleration of blocks B and C, relative to the ground b. Mass of each block (g = 10 ms 2) |
11 |
| 1361 | If the mass of a body is M on the surfrace of the earth, then its mass on the surface of the moon will be: A ( cdot frac{M}{6} ) в. ( M ) ( c cdot M+6 ) D. zero |
11 |
| 1362 | A glass vessel does not break when it falls on a hard floor, but it breaks when it falls on a carpet. State true or false. |
11 |
| 1363 | n balls each of mass m impinge elastically each second on a surface with velocity u. The average force experienced by the surface will be A . mnu B. ( 2 m n u ) c. ( 4 m n u ) D. ( m n u / 2 ) |
11 |
| 1364 | A boy is sitting on a horizontal platform in the shape of a disc at a distance of ( 5 m ) from its center. The boy begins to slip when the speed of wheel exceeds 10rpm. The coefficient of friction between the boy and platform is ( (g= ) ( left.10 m s^{-2}right) ) A ( cdot pi^{2} / 6 ) в. ( pi^{2} / 18 ) c. ( pi / 6 ) D. ( pi / 2 ) |
11 |
| 1365 | A bicycle is being peddled and is moving in the direction shown. What are the directions of the friction acting on the front wheel and on the back wheel? A. backwards B. front C. no friction D. all of the above |
11 |
| 1366 | A body is acted on by a force given by ( boldsymbol{F}=(mathbf{1 0}+mathbf{2 t}) mathrm{N} . ) The impulse received by the body during the first four seconds is : A . ( 40 mathrm{N} ) s B. 56 N s c. 72 N s D. 32 N s |
11 |
| 1367 | What effect will it have on the motion of the body if it is made to move on a sandy surface? |
11 |
| 1368 | A gun of mass M fires a bullet of mass ( mathrm{m} ) with a velocity v relative to the gun. The average force required to bring the gun to rest in 0.5 sec. is A ( cdot frac{2 mathrm{Mmv}}{mathrm{M}+mathrm{m}} ) в. ( frac{M m v}{2(M+m)} ) c. ( frac{3 mathrm{Mmv}}{2(mathrm{M}+mathrm{m})} ) D. ( frac{mathrm{Mmv}}{(mathrm{M}+mathrm{m})} ) |
11 |
| 1369 | A spehere of mass ( 0.2 mathrm{kg} ) is attached to an inextensible string of length ( 0.5 m ) whose upper end is fixed to the cielling. The sphere is made to describe a horizontal circle of radius ( 0.3 m ) The speed of the sphere will be |
11 |
| 1370 | Two cars ( A ) and ( B ) start from the same starting point. A is starting from rest and moving with constant acceleration ( 2 m / s^{2} ) and car ( B ) is starting with a constant velocity ( 40 mathrm{m} / mathrm{s} ). After what time both cars will meet each other? |
11 |
| 1371 | Suppose your writing desk is tilted a little, a book kept on it starts sliding down. The direction of frictional force acting on it is A. upwards B. downwards c. no direction D. cant say |
11 |
| 1372 | A cricket ball of mass ( 500 mathrm{g} ) is moving with a speed of ( 36 mathrm{km} h^{-1} . ) It is reflected with the same speed. What is the impulse applied on it? A. 20 kg m ( s^{-1} ) B. ( 5 mathrm{kg} mathrm{m} s^{-1} ) C. ( 25 mathrm{kg} mathrm{m} s^{-1} ) D. ( 10 mathrm{kg} mathrm{m} s^{-1} ) |
11 |
| 1373 | The maximum value of static friction is called limiting friction. A. True B. False c. Ambiguous D. Data insufficient |
11 |
| 1374 | A vehicle is running with a velocity of ( 5 m / s . ) If the momentum of the vehicle is ( 5000 mathrm{kg} mathrm{m} / mathrm{s}, ) What is its mass? A. ( 1 mathrm{kg} ) в. ( 100 mathrm{kg} ) c. ( 1000 k g ) D. ( 1.1 mathrm{kg} ) |
11 |
| 1375 | Three point charges, each ( +q ) are placed at the vertices of an equilateral triangle. What charge should be placed at its centroid so that all four charges are in equilibrium? A ( cdot frac{q}{sqrt{2}} ) B. ( frac{q}{sqrt{3}} ) c. ( frac{sqrt{3} q}{2} ) D. ( frac{2 q}{sqrt{3}} ) |
11 |
| 1376 | A block of mass m is placed on another block of mass M, which itself is lying on a horizontal surface. The coefficient of friction between two blocks is u, and that between the block of mass M and horizontal surface is M. What maximum horizontal force м. can be applied to the lower block so that the two blocks move without Fig. 7.263 separation? a. (M + m)(u2 – Mig b. (M-m)(u2 – U18 c. (M-mu,+ ug d. (M + m)(u2+ Mig |
11 |
| 1377 | Find minimum value of ( F ) required to slide this block. ( A cdot(1) 20 N ) B. (2) 40 ( c cdot(3) 60 ) D. (4) 120 ( mathrm{N} ) |
11 |
| 1378 | Two blocks ( A ) and ( B ) are connected by a light inextensible string passing over a fixed smooth pulley as shown in Fig. The coefficient of friction between the block A and B the horizontal table is ( mu=0.5 ) If the block ( A ) is just to slip, find the ratio of masses of the blocks. |
11 |
| 1379 | A stream of water flowing horozintally with a speed of ( 15 mathrm{ms}^{-1} ) gushes out of a tube of cross-sectional area ( 10^{-2} m^{2} ) and hits a vertical wall nearly. The force exerted on the wall by the impact of water assuming it does not rebound is A ( cdot 2.25 times 10^{3} N ) В. ( 2.5 times 10^{3} N ) c. ( 3.0 times 10^{3} N ) D. ( 35 times 10^{3} N ) |
11 |
| 1380 | 24. The acceleration of m, is -ms-2 ms-2 20 ms² d. 178 ms ² |
11 |
| 1381 | A projectile of mass ( m ) is fired with velocity ( v ) from a point as shown in figure, neglecting air resistance, what is the change in momentum when leaving ( P ) and arriving at ( Q ? ) ( A cdot 0 ) ( mathbf{B} cdot m v ) ( mathbf{c} cdot 4 m v ) D. ( frac{2 m v}{sqrt{3}} ) |
11 |
| 1382 | A circular track of radius ( 300 mathrm{m} ) is banked at an angle ( frac{pi}{12} ) radian. If the coefficient of friction between wheel of a vehicle and road is ( 0.2, ) the maximum safe speed of vehicle is : A ( cdot 28 m s^{-1} ) B . 38 ( m s^{-1} ) ( mathrm{c} cdot 18 mathrm{ms}^{-1} ) D. ( 48 mathrm{ms}^{-1} ) |
11 |
| 1383 | Assertion Swimming is possible due to third law of motion Reason Rebounding of rubber ball takes place due to third law of motion. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion C. Assertion is correct but Reason is incorrect D. Both Assertion and Reason are incorrect |
11 |
| 1384 | Change in the state of rest or of uniform motion is brought about by: A. Acceleration B. Force c. Energy D. None |
11 |
| 1385 | A small ring of mass ( mathrm{m} ) is connected with a particle of same mass by an ideal string and the whole system is released as shown in figure. Coefficient of friction between ring ( A ) and wire is ( 3 / 5 . ) If ring A starts sliding when connecting string makes an angle ( theta ) with the vertical. This angle ( theta ) is (particle is free to move and ring can slide only): A .30 в. 45 ( c .60 ) D. None of these |
11 |
| 1386 | A parachutist with total weight ( 75 k g ) drops vertically onto a sandy ground with a speed of ( 2 m s^{-1} ) and comes to a halt over a distance of 0.25 m. The average force from the ground on her is close to ( mathbf{A} cdot 600 N ) в. ( 1200 N ) c. ( 1350 N ) D. ( 1950 N ) |
11 |
| 1387 | A home-owner pushes a lawn mower across a horizontal patch of grass with a constant speed by applying a force ( P ) The arrows in the diagram correctly indicate the directions but not necessarily the magnitudes of the various forces on the lawn mower. Which of the following relations among the various force magnitudes, ( mathbf{W}, mathbf{f}, mathbf{N}, mathbf{P} ) is correct? ( A cdot P>f ) and ( N>W ) B. ( Pf ) and ( NW ) |
11 |
| 1388 | Assertion According to Newton’s third law, the sum of action and reaction forces on a body is equal to zero. Reason The action and reaction forces act on different bodies. A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion c. Assertion is correct but Reason is incorrect D. Assertion is incorrect but Reason is correct |
11 |
| 1389 | A Gardner waters the plants by a pipe of diameter 1 mm. The water comes out at the rate or ( 10 mathrm{cm}^{3} / ) sec. The reaction force exerted on the hand of the Gardner is: A. 0 N В. ( 1.27 times 10^{-2} N ) c. ( 1.27 times 10^{-4} N ) D. 0.127 |
11 |
| 1390 | A car taken a turn along a curved road of radius ( 40 mathrm{m} ) and the angle of banking of the road is ( 45^{circ} . ) At what maximum speed can the car be driven so that it may not skid. ( left(boldsymbol{g}=mathbf{1 0} boldsymbol{m s}^{-2}right) ) A ( cdot 20 m s^{-1} ) B. ( 10 mathrm{ms}^{-1} ) c. ( 5 m s^{-1} ) D. ( 1 mathrm{ms}^{-1} ) |
11 |
| 1391 | A 1 m long uniform beam is balanced as shown. Calculate the force ( F ) ( A cdot 2 N ) B. 3 N ( c cdot 7 N ) D. ( 11 N ) |
11 |
| 1392 | In a one dimensional collision between two identical particles ( A ) and ( B, B ) is stationary and ( A ) has momentum ( p ) before impact. During impact, ( B ) gives impulse ( J ) to ( A ) This question has multiple correct options A. The total momentum of the ( A+B ) system is ( p ) before and after the impact, and ( (p-J) ) during the impact B. During the impact ( A ) gives impulse of magnitude ( J ) to ( B ) c. the coefficient of restitution is ( frac{2 J}{p}-1 ) D. The coefficient of the restitution is ( frac{J}{p}+1 ) |
11 |
| 1393 | ( frac{Y}{L} ) | 11 |
| 1394 | Which of the following factors affect friction? A. Nature of the surface B. Weight of the object placed over other C. Motion or speed of the object D. All of the above |
11 |
| 1395 | Passengers standing in a bus are thrown outwards when the bus takes a sudden turn. This is due to: A. outward pull on them B. inertia c. change in momentum D. change in acceleration |
11 |
| 1396 | A mass of ( 4 mathrm{kg} ) rest on the horizontal plane. The plane is gradually inclined until at an anger of ( theta=15^{circ} ) with the horizontal, The mass just begin the block & the surface |
11 |
| 1397 | A force ( f_{1} ) pushes on an object of mass ( 10 mathrm{kg} ) with a force of ( 5 mathrm{N} ) to the right. ( mathrm{A} ) force pushes on the same object with a force ( f_{2} ) of ( 15 mathrm{N} ) to the left. What is the acceleration of the object? A ( cdot 0.3 mathrm{m} / mathrm{s}^{2} ) to the left B. ( 0.5 mathrm{m} / mathrm{s}^{2} ) to the left C. ( 1 mathrm{m} / mathrm{s}^{2} ) to the left D. ( 1.5 mathrm{m} / mathrm{s}^{2} ) to the left E ( cdot 10 m / s^{2} ) to the left |
11 |
| 1398 | Figure shows two blocks in contact sliding down an inclined surface of inclination ( 30^{0} . ) The friction coefficient between the block of mass ( 2.0 mathrm{kg} ) and the incline is ( mu_{1}=0.20 ) and that between the block of mass ( 4.0 mathrm{kg} ) and the incline is ( mu_{2}=0.30 . ) Find the acceleration of ( 2.0 mathrm{kg} ) block. ( g= ) ( 10 m / s^{2} ) ( mathbf{A} cdot 3.8 m / s^{2} ) ( mathbf{B} cdot 5.1 mathrm{m} / mathrm{s}^{2} ) ( mathbf{c} cdot 1.2 mathrm{m} / mathrm{s}^{2} ) D. ( 2.7 mathrm{m} / mathrm{s}^{2} ) |
11 |
| 1399 | State whether given statement is True or False. The actual force applied by the brakes may be slightly less than the calculated |
11 |
| 1400 | Suppose gravity of earth suddenly becomes zero, then in which direction will the moon begin to move if no other celestial body affects it? A . Radial B. Tangential c. cant say D. None |
11 |
| 1401 | Can a body have energy without having momentum ? Explain? | 11 |
| 1402 | The combined effect of mass and velocity is taken into account by a physical quantity called: A. Moment of momentum B. Moment of force c. Momentum D. None of these |
11 |
| 1403 | A ball moving with a velocity v hits a massive wall moving towards the ball with a velocity u. An elastic impact lasts for time ( Delta t ), Then : This question has multiple correct options A. the average elastic force acting on the ball is ( [m(u+ ) ( v)] / Delta t ) B. the average elastic force acting on the ball is ( [2 m(u+ ) ( v)] / Delta t ) c. the kinetic energy of the ball increases by 2 mu ( (u+v) ) D. the kinetic energy of the ball remains the same after the collision |
11 |
| 1404 | If ( sqrt{3} ) is static friction coefficient, what is the angle of inclination of incline at which the body will start sliding? A ( .90^{circ} ) B . ( 60^{circ} ) c. 45 D. 30 |
11 |
| 1405 | 6. A block of mass 0.1 kg is held against a wall applying a horizontal force of 5 N on the block. If the coefficient of friction between the block and the wall is 0.5, the magnitude of the friction force acting on the block is (IIT JEE, 1994) a. 2.5 N b. 0.98 N c. 4.9 N d. 0.49 N A n ne -1. 1mienbariaal |
11 |
| 1406 | A T-shaped object with dimensions shown in the figure is lying on a smooth floor. A force ( vec{F} ) is applied at the point ( mathrm{P} ) parallel to ( A B, ) such that the object has only the translational motion without rotation. Find the location of P with respect to ( mathbf{C} ) |
11 |
| 1407 | ( = ) | 11 |
| 1408 | 1d the wedge 62. A small block of mass m rests on a smooth wedge of an O. With what horizontal acceleration a should the we be pulled, as shown in Fig. 6.342, so that the block full freely? m Fig. 6.342 b. g sin & c. g cot d. g tano a. g cos 0 |
11 |
| 1409 | ( boldsymbol{n} ) small balls each of mass ( boldsymbol{m} ) impinge elastically each second on a surface with velocity ( v ). The force experienced by the surface will be : A ( cdot frac{1}{2} m n v ) B. ( 2 m n v ) c. ( m n v ) D. ( 4 m n v ) |
11 |
| 1410 | If the road of the previous problem is horizontal (no banking), what should be the minimum friction coefficient so that a scooter going at ( 18 mathrm{km} / mathrm{h} ) does not skid? A . 0.15 B. 0.2 ( c .0 .25 ) D. 0.5 |
11 |
| 1411 | A circular track of radius ( 100 mathrm{m} ) is designed for an average speed ( 54 mathrm{km} / mathrm{h} ) Find the angle of banking. A ( cdot tan ^{-1}left(frac{3}{20}right) ) B. ( tan ^{-1}left(frac{9}{40}right) ) c. ( tan ^{-1}left(frac{3}{10}right) ) D. None of these |
11 |
| 1412 | What should be the minimum force ( boldsymbol{P} ) to be applied to the string so that block of mass ( m ) just begins to move up the frictionless plane. ( mathbf{A} cdot M g tan theta / 2 ) в. ( M g cot theta / 2 ) c. ( frac{M g cot theta / 2}{1+sin theta} ) D. ( M g cos theta / 2 ) |
11 |
| 1413 | According to Newton’s second law of motion, the force acting on a body acts in the direction of : A. Velocity B. Acceleration c. Momentum D. wind velocity |
11 |
| 1414 | Consider the following statement. When jumping from some height, you should bend your knees as you come to rest instead of keeping your legs stiff. Which of the following relations can be useful in explaining the statement? where symbols have their usual meaning. A ( cdot Delta P_{1}=-Delta P_{2} ) B. ( Delta E=-Delta P E+K E=0 ) c. ( F Delta t=-m Delta F ) D. ( Delta x propto Delta F ) |
11 |
| 1415 | Why is it easier to pull a lawn roller than to push it? A. Pulling involves sliding friction B. Pulling involves dry friction. c. Pulling increases the effective weight. D. Pulling decreases normal reaction |
11 |
| 1416 | A ( 5-mathrm{Kg} ) block is projected upwards with an initial speed of ( 10 m s^{-1} ) from the bottom of a plane inclined at ( 30^{0} ) with horizontal. The coefficient of kinetic friction between the block and the plane is 0.2. a. How far does move up the plane? b. How long does it move up plane? c. After what time from its projection does the block again come back to the bottom? With what speed does it arrive? |
11 |
| 1417 | A body of mass ( mathrm{m} ) is kept on an inclined plane of inclination ( 30^{0} ) to the horizontal. If the angle of repose is ( 45^{0} ) static friction on the body is A ( cdot frac{m g}{sqrt{2}} ) B. ( frac{m g}{2} ) ( mathrm{c} cdot mathrm{mg} ) D. ( sqrt{2} m g ) |
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| 1418 | 12 A ball of mass (m) 0.5 kg is attached to the end of a string having length (L) 0.5 m. The ball is rotated on a horizontal circular path about vertical axis. The maximum tension that the string can bear is 324 (A—– N. The maximum value of angular Fig. 7.365 velocity of ball (in rad s ) is (IIT JEE, 2011) b. 18 c. 27 d. 36 a. 9 |
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| 1419 | A student is weighing an object using a spring balance. The weight and mass of the object are respectively ( left(boldsymbol{g}=mathbf{1 0 m} / boldsymbol{s}^{2}right) ) A. ( 25 N, ) skg в. ( 50 N, 5 k g ) c. ( 25 N, 2.0 k g ) D. ( 50 N, 2.5 k g ) |
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| 1420 | ritustration 6.23 A man of mass M stands on a weighing machine in an elevator accelerating upwards with an acceleration a. Draw the free-body diagram of the man as observed by the observer A (stationary on the ground) and observer B (stationary on the elevator). Also, calculate the reading of the weighing machine. |
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| 1421 | A particle having a charge ( 10 mathrm{mC} ) is held fixed on a horizontal surface. A block of mass 80 g and having charge stays in equilibrium on the surface at a distance of ( 3 mathrm{cm} ) from the first charge. The coefficient of friction between the surface and the block is ( mu=0.5 . ) Find the range within which the charge on the block may lie A. ( -4 times 10^{-12} mathrm{C} ) to ( 4 times 10^{-12} mathrm{C} ) B. ( -2 C ) to ( 2 times 10^{2} C ) ( mathbf{c} .-4 times 10^{-19} mathrm{C} ) to ( 4 times 10^{-19} mathrm{C} ) D. ( -2 times 10^{-19} mathrm{C} ) to ( 2 times 10^{-19} mathrm{C} ) |
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| 1422 | A block of mass ( 2 k g ) is free to move along the ( X ) -axis. It is at rest and from ( t=0 ) onwards it is subjected to a time- dependent force ( F(t) ) in the ( x ) direction. The force ( F(t) ) varies with ( t ). the kinetic energy of the block after 4.5 second is? |
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| 1423 | A body of mass ( 5 k g ) is moving with velocity ( 2 m s^{-1} . ) Calculate its linear momentum A ( .2 .5 mathrm{kg} mathrm{ms}^{-1} ) B. ( 10 mathrm{kg} mathrm{ms}^{-1} ) c. 5 kg ( m s^{-1} ) D. ( 20 mathrm{kg} mathrm{ms}^{-1} ) |
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| 1424 | A ball of mass ( 1 k g ) dropped from ( 9.8 m ) height strikes the ground and rebounds to a height of ( 4.9 m ). If the time of contact between ball and ground is ( 0.1 s ) then find impulse and average force acting on ball. |
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| 1425 | Consider two perfectly elastic spheres having velocities ( u_{1} ) and ( u_{2} ) in the same direction and masses ( m ) and ( m^{prime} . ) When these two spheres collide, the impulse of the blow on the spheres is A ( cdot frac{2 m m^{1}}{m+m^{1}}left(u_{1}-u_{2}right) ) в. ( frac{2 m m^{1}}{m-m^{1}}left(u_{1}-u_{2}right) ) c. ( frac{2 m m^{1}}{m+m^{1}}left(u_{1}+u_{2}right) ) D. ( frac{2 m m^{1}}{m-m^{1}}left(u_{1}+u_{2}right) ) |
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| 1426 | Two masses ( A ) and ( B ) of ( 10 mathrm{Kg} ) and ( 5 mathrm{Kg} ) respectively are connected with a string passing over a frictionless pulley at a corner of a table a shown in the adjoining diagram. The coefficient of friction of ( A ) with the table is ( 0.2 . ) The minimum mass of ( C ) that may be placed on ( A ) to prevent it from moving is equal to? |
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| 1427 | Which law of motion deals with inertia: A. Third law of motion B. Second law of motion c. First law of motion D. All of these |
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| 1428 | A blog of mass ( mathrm{m} ) is placed on a cart of mass ( mathrm{M} ) as shown in the figure, The coefficient of friction between the block and the cart is ( mu . ) What is the minimum acceleration of the cart so that block ( m ) does not slip on the cart? |
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| 1429 | A hammer of mass 5 kg moving with a speed of ( 2 mathrm{m} mathrm{s}^{-1} ) strikes the head of a nail driving it ( 20 mathrm{cm} ) into the wall. Find the impulse. A . ( 10 mathrm{N} ) s B. 20 N s c. 30 N s D. 40 N s |
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| 1430 | Two smooth cylindrical bars weighing Weach lie next to each other in contact. A similar third bar is over the two bars as shown in figure. Neglecting friction, the minimum horizontal force on each lower bar necessary to keep them together is A ( cdot frac{W}{2} ) в. c. ( frac{W}{sqrt{3}} ) D. ( frac{W}{2 sqrt{3}} ) |
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| 1431 | Friction is a type of: A. resistance force B. non contact force c. contact force D. motion |
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| 1432 | Assuming the water resistance to be negligible, find the horizontal component of the force with which the man acted on the raft during the motion. ( ^{mathrm{A}} cdot_{F}=-frac{2 m M}{M+m} frac{d v^{prime}}{d t} ) ( ^{mathrm{B}} cdot_{F}=frac{2 m M}{M+m} frac{d v^{prime}}{d t} ) c. ( _{F}=frac{m M}{M+m} frac{d v^{prime}}{d t} ) D. ( F=-frac{m M}{M+m} frac{d v^{prime}}{d t} ) |
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| 1433 | With increase of temperature, the frictional force acting between two surfaces: A . increases B. decreases c. remains same D. may increases or decreases |
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| 1434 | 0. A balloon of mass Mis descending at a constant acceleration a. When a mass m is released from the balloon, it starts rising with the same acceleration a. Assuming that its volume does not change, what is the value of m? a a. Q-M . 2a b. a +g 20 M a +8 a+SM at 8 M a – 20 O tout |
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| 1435 | A car is moving on a circular track of radius ( R ). The road is banked at ( theta . mu ) is the coefficient of friction. Find the maximum speed the car can have. ( mathbf{A} cdotleft[frac{R g(sin theta+mu cos theta)}{cos theta+mu sin theta}right]^{1 / 2} ) B. ( left[frac{R g(cos theta+mu sin theta)}{cos theta-mu sin theta}right]^{1 / 2} ) ( ^{mathbf{C}} cdotleft[frac{R g(sin theta+mu cos theta)}{cos theta-mu sin theta}right]^{1 / 2} ) D. None |
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| 1436 | In a large commercial complex there are four ways to reach the main road. One of the path has loose soil, the second is laid with polished marble, the third is laid with bricks and the fourth has gravel surface. It is raining heavily and Paheli wishes to reach the main road. The path on which she is least likely to slip is: A. loose soil B. polished marble c. bricks D. gravel surface |
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| 1437 | wedge as the ass m, lies on un in Fig. 6,3326 49. A block of mass m, lies on the top of fixed wedge in Fig. 6.332(a) and another block of mass m la of wedge which is free to move as shown in Fie At time=0, both the blocks are released from rest vertical height h above the respective horizontal surf which the wedge is placed as shown. There is no fru between block and wedge in both the figures. Let T. To be the time taken by the blocks, respectively, to reach the horizontal surface. Then om rest from wal surface on is no friction Fixed wedge (a) Horizontal surface (b) Smooth horizontal surface Fig. 6.332 a. Ti > T2 c. Ti = T2 b. T, <T, d. Data insufficient |
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| 1438 | 32. For the pulley system shown in Fig. 6.317, each of the cables at A and B is given a velocity of 2 ms’ in the direction of the arrow. Determine the upward velocity v of the load m. Fig. 6.317 a. 1.5 ms- b. 3 ms-1 c. 6ms-1 d. 4.5 ms-1 |
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| 1439 | A plane banks its wings ( 30^{circ} ) relative to the horizontal to enter into a circular turn. The circular path has a radius of ( 1500 m ) Which of these values best represents the velocity of the plane if the lift force exerted on the wings is equal to twice the weight of the plane? A. ( 120 m / s ) в. ( 140 mathrm{m} / mathrm{s} ) c. ( 160 mathrm{m} / mathrm{s} ) D. 240m/s E. ( 320 m / s ) |
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| 1440 | A point source of light is placed at the centre of curvature of a hemispherical surface. The radius of curvature is r and the inner surface is completely reflecting. Find the force on the hemisphere due to the light falling on it if the source emits a power ( mathbf{W} ) |
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| 1441 | Consider the following two statement- [A] Linear momentum of a system of particle is zero [B] kinetic energy of a system of particles is zero. Then A. A does not imply B but B implies A B. A implies B and B implies A c. A does not imply B & B does not imply A D. A implies B but B does not imply A |
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| 1442 | Which of the following best describe about the statement “An object slides on a horizontal, frictionless surface”. A. Inertia B. Unbalanced forces C. Action and reaction force pairs D. Universal gravitation E. simple harmonic motion |
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| 1443 | A hammer of mass 5 kg moving with a speed of ( 2 m s^{-1} ) strikes the head of a nail driving it ( 20 mathrm{cm} ) into the wall. Find the impulse(in N s). ( A cdot O ) B. -100 ( c .-10 ) D. -10000 |
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| 1444 | A body of mass 5 kg undergoes a change in speed from 20 to ( 0.20 mathrm{m} / mathrm{s} ) The momentum of the body would: A. increase by ( 99 mathrm{kg} mathrm{m} / mathrm{s} ) B. decrease by ( 99 mathrm{kg} mathrm{m} / mathrm{s} ) c. increase by ( 101 mathrm{kg} mathrm{m} / mathrm{s} ) D. decrease by ( 101 mathrm{kg} mathrm{m} / mathrm{s} ) |
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| 1445 | A person carries a hammer on his shoulder and holds the other end of its light handle in his hand. Let ( y ) be the distance between his hand and the point of support. If the person changes ( y ), the pressure on his hand will be proportional to: ( mathbf{A} cdot y ) В . ( y^{2} ) ( c cdot frac{1}{y} ) D. ( frac{1}{y^{2}} ) |
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| 1446 | A body of mass ( 2 k g ) slides down a plane inclined at an angle of ( 30^{circ} ) with horizontal. The co-efficient of friction between the body and the plane is ( sqrt{frac{3}{2}} ) What force must be applied on the body so that it moves down without acceleration? A. ( 11 N ) в. ( 14.7 sqrt{2} N ) c. zero D. None of these |
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| 1447 | Suppose you push a spring with a force ( F_{1} ) as shown in figure, the spring also pushes up on your hand with a force ( F_{2} ) What is the relationship between ( boldsymbol{F}_{1} ) and ( F_{2} ? ) A ( cdot F_{1}>F_{2} ) B ( . F_{1}=2 F_{2} ) ( mathrm{c} cdot F_{1}<F_{2} ) D. ( F_{1}=F_{2} ) |
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| 1448 | Find the magnitude ( & ) direction of frictional force between block ( A ) and table, if block ( A ) is pulled towards left with a force of ( 50 N ) ( mathbf{A} cdot 10 hat{i} ) B . ( 10 hat{j} ) ( c cdot 20 hat{i} ) D. ( 20 hat{j} ) |
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| 1449 | If an external force and the frictional force are acting on a body, which is in rest on the floor, and are equal and opposite, then the frictional force is: A. rolling friction. B. sliding friction. C. static friction. D. Both B and C |
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| 1450 | In Fig. 6.334, a person wants to rise a block lying on the ground to a height h. In both the cases, if the time required is same, then in which case he has to exert more force? Assume pulleys and strings light. a. (i) or c. Same in both Fig. 6.334 b. (ii) d. Cannot be determined |
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| 1451 | Friction is ( quad ) in some situations. A. desirable B. undesirable c. both ( A ) and ( B ) D. none of the above |
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| 1452 | A particle is released on a vertical smooth semicircular track from point ( X ) so that ( O X ) makes an angle ( theta ) from the vertical (see figure). The normal reaction of the track on the particle vanishes at point ( Y ) where ( O Y ) makes and angle ( phi ) with the horizontal. then: ( A cdot sin phi=cos theta ) B. ( sin phi=frac{1}{2} cos theta ) c. ( sin phi=frac{2}{3} cos theta ) D. ( sin phi=frac{3}{4} cos theta ) |
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| 1453 | A block is given a initial push along rough horizontal fixed table surface and after some time it stops due to friction. For the system of block and table A. temperature increase B. heat supplied is positive c. heat supplied is negative D. total energy decreases |
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| 1454 | Free body diagrams doesn’t play any role in making the calculations on the conditions of the equilibrium of the body. A . True B. False |
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| 1455 | 2. The magnitude of the normal reaction that acts on the block at the point Q is a. 7.5 N b. 8.6 N c. 11.5 N d. 22.5 N |
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| 1456 | Three coplanar forces keep a body in equilibrium. The angles between adjacent forces are in the ratio of 3: 4: 5. The ratio of maximum force to the minimum force is A в. ( c cdot frac{4}{3} ) D. 2 |
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| 1457 | A metallic rod of mass ( 20 mathrm{kg} ) and of uniform thickness rests against a wall while the lower end of rod is in contact with rough floor. The rod makes an angle ( 60^{0} ) with floor. If the weight of rod produces a torque ( 150 mathrm{Nm} ) about its lower end, the length of rod ( (g= ) ( left.10 m s^{-2}right) ) is: ( mathbf{A} cdot 1.5 m ) B. ( 2 m ) ( c .3 m ) D. ( 4 m ) |
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| 1458 | A windmill is pushed by four external forces as shown. Calculate force required to make the windmill stand still. ( A cdot 2 N ) В. -4 N ( c .6 N ) D. ( -16 N ) |
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| 1459 | An iron ball of mass ( boldsymbol{m}=mathbf{5 0} boldsymbol{g} ) falls from a height of ( h_{1}=5 m ) and rises upto ( h_{2}=2 m ) after colliding with the horizontal surface. If the time of the glass half is ( Delta t=0.02 s, ) find the average contact force exerted on the ball by the horizontal surface. |
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| 1460 | Radius of curvature of a road is ( 60 mathrm{m} ). It is a to be banked so that no friction force is required for a car travelling on the road at ( 25 mathrm{mt} / mathrm{sec} ). Find the angle of banking? A ( .47^{circ} ) B . ( 45^{circ} ) ( c .90 ) D. ( 180^{circ} ) |
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| 1461 | What is the momentum versus velocity graph is like, when mass is fixed? A. Straight line B. Exponential curve c. Parabola D. circle |
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| 1462 | 7. A small object of mass 0.5 kg is attached to an end of a mass less 2 m long rope. It is rotated under gravity in a vertical circle with the other end of the rope being at the centre of the circle. The motion is started from the lowest point. Match columns I and II. Column I Column II If the speed of the a. there will be some point on object at lowest point the circle at which speed of is 3.5 ms -1 the object is zero but ten- sion in the rope is not zero. If the speed of the b. there will be some point on object at lowest point the circle at which tension is 8 ms -1 in the rope is zero but speed of the object is not zero. iii. If the maximum ten- c. the object will not be able sion in the rope is to reach the highest point 15 N iv. If the maximum ten- d. the object will be able to sion in the rope is reach the highest point 30 N |
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| 1463 | Which of the following factors affects friction? A. Nature of the surface B. Weight of object placed over other C. Amount of surface area in contact between the moving bodies D. Both A and B |
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| 1464 | Which of the following equations or principle is most suitable to solve given question.
A block of mass ( m ) remains at rest on a |
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| 1465 | If the momentum of a body is doubled, the kinetic energy is A. Halved B. Unchanged c. Doubled D. Becomes 4 times |
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| 1466 | A ( 4 g ) bullet is fired horizontally with a speed of ( 300 m / s ) into ( 0.8 k g ) block of wood, which is at rest on a table. If the coefficient of friction between the block and the table is ( 0.3, ) how far will the block slide approximately? A. ( 0.20 mathrm{m} ) B. 0.375 m c. ( 0.565 mathrm{m} ) D. 0.750 ( mathrm{m} ) |
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| 1467 | A ball of mass ( 50 g m ) is dropped from a height ( h=10 m . ) It rebounds losing 75 percent of its kinetic energy. If it remains in contact with the ground for ( Delta t=0.01 ) sec., the impulse of the impact force is: A. ( 1.3 N-s ) B. ( 1.05 N-s ) c. ( 1300 N-s ) D. ( 015 N-s ) |
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| 1468 | Which of the following statement is CORRECT? A. rolling a body is easier than sliding B. sliding a body is easier than rolling C. rolling a body is harder than sliding D. None of these |
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| 1469 | Which of the following describe a frictional force? This question has multiple correct options |
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| 1470 | A ball of mass ( 5 k g ) is suspended from a chord of length ( l=0.5 m ) is attached to a cart ( A ) of mass ( 2.5 k g ), which slides freely on a frictionless horizontal track as shown in figure. The ball given an initial horizontal velocity 1 m / ( s ) relative to the ground while the cart is at rest. Find (a) The velocity of the ball when string makes minimum angle with vertical (b) The maximum vertical distance through which the ball will rise. |
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| 1471 | A man is standing on a platform of a balance and takes a quick step, then his weight: A . decreases B. increases c. remains unchanged D. fi |