# Laws Of Motion Questions

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 NoQuestionsClass
1The 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
11
2If 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
11
3Match 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
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 )
11
4For 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^{-} )
11
5Distinguish between Inertia of motion and inertia of direction11
6Which 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
11
7The 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
11
82. 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
11
9An 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} )
11
10A 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
11
11The 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
11
12An 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).
11
13A 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
A ( cdot frac{v^{2} b}{R g} )
в. ( frac{v b}{R g} )
( c )
( D )
11
14If 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
11
15A 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 )
11
16Assertion: 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
11
1741. 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
11
18a
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
11
19A 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
11
20A 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} )
11
21A 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} )
11
22980. 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
11
23A 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 )
11
24Block 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.
11
25A person standing in a moving bus falls backwards when bus suddenly starts moving in forward direction. This happens due to11
26Example 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
11
27Two 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} )
11
28A 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} )
11
29A ( 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} )
11
30An 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.
11
31A 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.
11
32In 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
11
33Assertion
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
11
34Which 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
11
35A 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
11
36A 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
11
37Find 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 )
11
38A cricketer catches a ball of mass ( 150 g ) in ( 0.1 s ) moving with speed ( 20 m / s )
then the experiences force of
11
39The 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)} )
11
40A 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
11
41The 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} )
11
42The 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
11
43Hence, 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
11
44A 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} )
11
45Two 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?
11
46A 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 )
11
47A 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
11
48An 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
11
49A ( 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} )
11
506. 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
11
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
11
5233. 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
11
53The 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
11
54It 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
11
55A 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} )
11
56Normal force is
A. parallel to the surface
B. perpendicular to the surface
( c cdot ) both
D. none
11
57A 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
11
A. To increase friction
B. To decrease friction
c. To multiply friction
D. To decrease grip
11
59Which 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
11
60Two 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.
11
61U. -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
11
62Define angle of repose. Deduce its relation with coefficient of limiting
friction.
11
63The 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} )
11
64A 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) )
11
65A 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
11
66Four 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 )
11
67In 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} )
11
68An 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} )
11
69Two 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} )
11
70Frictional force always opposes motion
of a body.
A . True
B. False
11
71A 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} )
11
72A 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
11
73A 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.
11
74A 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 )
11
7540. 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
11
76A 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.
11
77A 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
11
78Boats and aeroplanes are ( ldots ldots . . . . . . . . ) so as
to reduce fluid friction.fill in the blank.
A. large
c. streamlined
D. bigger
11
79A 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
11
80A 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
11
81A ( 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} )
11
82A 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
11
83List the effects of force with example11
84An 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 )
11
85Cleaning of dust from carpet is due to
A. Inertia of motion
B. Inertia of rest
c. Inertia of direction
D. Momentum
11
86A 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
11
87A 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
11
88If 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
11
89The 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 )
11
90calculate 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 )
11
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 )
11
92A 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?
11
93o 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.
11
94Momentum is a measure of quantity of motion.
A . True
B. False
11
957. 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
11
96Explain why objects moving in fluids must have special shapes.11
97A 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} )
11
98A 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
11
99If 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
11
100A 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
11
101Find 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 )
11
102Block 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
11
103If 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
11
104Inertia 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
11
105Two 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?
11
1062. 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
11
107The 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?
11
108Which of the following has more inertia
( ? )
A five-rupee coin or a one-rupee coin.
11
109Illustration 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.
11
110A 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} )
11
111Assertion
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
11
112Assertion
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
11
113Why 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)
11
115Two 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} )
11
116Distinguish between static friction, limiting friction and kinetic
friction.How do they vary with the applied force? Explain by diagram.
11
117Sliding friction is ( ldots ldots . . . . . . . . ) than rolling friction.fill in the blank.
A. greater
B. less
c. same as
D. cant say
11
118A 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} )
11
119What 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} )
11
120A 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} )
11
121If the mass of the body is doubled what’ll happen to its acceleration if the same force applied.11
122According 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
11
123A 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
11
124T
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.
11
125s the block gets
50. At what angle with horizontal does the block
separated from the track?
d. never leaves contact with the track
11
126Two 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.
11
127A 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}} )
11
128The 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
11
129A 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 )
11
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
11
1313. 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
11
132As 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
11
133Inertia is
A. a property of matter
B. a type of force
C. the speed of an object
D. none of the above
11
134Two 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
11
135Maximum force exerted by the bat on the ball is:
A ( .2500 N )
в. ( 5000 N )
c. ( 7500 N )
D. ( 1250 N )
11
136In 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
11
137Statement 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
11
138Deformation 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
11
139An 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) )
11
140Choose 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
11
141Fill in the blanks with suitable words:
Newtons first law of motion is also
called law of
11
142A 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
11
143State whether True or False:
The angle through which cyclist should bend will be greater for the sharper
curve
A. True
B. False
11
144The 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.
11
1457. 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
11
146Discuss 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}} )
11
147Two 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} ) ).
11
148A 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 )
11
149Illustration 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
11
150Consider 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
11
151Two 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)
11
152A 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 )
11
153A plank with a box on it at one end is
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
11
154Determine the magnitude of frictional
force ( f ) in each of the following cases:
c)
11
155The 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} )
11
15636. 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
11
157For 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 )
11
158A 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} )
11
159A 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
11
160A ( 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} )
11
161A 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.
11
162If the K.E. of a body is increased by ( 300 % ) its momentum will increase by
A. ( 100 % )
B. ( 150 % )
c. ( sqrt{300 %} )
D. ( 175 % )
11
163What is the impulse of force shown in the following fingre?
A. 205 Ns
B. 450 Ns
( c .800 mathrm{Ns} )
D. 1000 Ns
11
164Assertion
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
11
165Five 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} )
11
166If 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
11
167Fig. 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
11
168A 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
11
169A 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 )
11
170A 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
11
171Explain why pulling is easier than
pushing with a neat sketch on a rough horizontal plane.
11
172T
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
11
173f 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
11
174State first law of motion and explain it11
175Assertion
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
11
176Two 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} )
11
177Friction does not depend on the nature of the surface in contact.
A. True
B. False
c. Ambiguous
D. Data insufficient
11
178An 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
11
179A 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
11
180OUV
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
11
181A 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
11
182What 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 )
11
183A 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 )
11
184Reason out in which case the frictional
force between the car and the road is
less.
11
185Guess and write why does pole vault jumper land on thick mats of foam?11
186A 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.
11
187Graphite powder is used in machines to
A. enhance friction
B. enhance profit
c. reduce friction
D. reduce efficiency
11
18899. 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
11
189Why is it dangerous to jump out of a
moving bus?
11
190Assertion
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
11
191A 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
11
192A 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
11
193Which of the following motion of law is (are) involved in the motion of the
rocket?

This question has multiple correct options
A. Newton’s first law of motion
B. Newton’s second law of motion
c. Newton’s third law of motion
D. All of the above

11
194powder sprinkled on a carrom board
A. magnifies friction.
B. reduces friction
c. removes friction.
D. does not affect friction
11
195A 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
11
196Assertion
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.
11
197State whether given statement is True or False. An object moving on a frictionless horizontal surface should move with
constant velocity
A. True
B. False
11
198Impulse is a scalar quantity. State true or false.
A . True
B. False
11
199A 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
11
200A 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}} )
11
201State 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} )
A. True
B. False

11
202The 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} )
11
203The 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?
11
204It is advised to tie any luggage kept on the roof of the bus with a rope.Why?11
205A 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
11
206A 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
11
207An 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} )
11
208A 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
11
209The 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
11
2103. 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.
11
211A 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} )
11
212A 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} )
11
213Assertion
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
11
214Sing
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)
11
215a.
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
11
216Is linear momentum of a system always
conserved?
11
217A 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
11
218m 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
11
219f 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 )
11
220One 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
11
221Frictional force is nearly negligible on:
A. Rough surfaces
B. Semi-smooth surfaces
c. Smooth surfaces
D. None of these
11
222A 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} )
11
223Which 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
11
224Value(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
11
225Find the frictional force on the ( 2-mathrm{kg} )
block in the arrangement shown in Fig.
11
226Inertia means resistance to the change
of state.
A . True
B. False
11
227When a running horse suddenly stops, the rider falls
A. forwards
B. backwards
c. to his right
D. to the horse’s right
11
228A 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
A. 0.33
B. 4.
c. 0.67
D. 0.8
11
229Friction is a/an
B. necessary evil
C. important force in daily life
D. all the above
11
230A 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
11
231What 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) )
11
232Due 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 )
11
233While 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
11
234Assertion
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
11
235The 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
11
236State 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
11
237The 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
11
238Let ( 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 )
11
239Two 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
11
240A ( 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
11
241While 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
11
242State whether true or false.
A ball thrown upwards in a train moving with uniform velocity returns to the
thrower
A. True
B. False
11
243Newton’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)
11
244Assertion
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
11
245For 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
11
246Illustration 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
11
247Two 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.
11
248A 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 )
11
2491 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)
11
250Where 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
11
251A 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
252The 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
11
253Consider the situation shown in the
figure. The tension in the string attached to ( 0.50 mathrm{kg} )
11
254A 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
11
255Mention the methods used to decrease
friction
11
256Inertia of a body has direct dependence
on:
A. velocity
B. mass
c. area
D. volume
11
257Match the column11
258A 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 )
11
259A 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 )
11
260Which 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
11
261Assertion
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
11
262A 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 )
11
263In 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.
11
264Complete 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
11
265A 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
11
266Ond
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.
11
26775. 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
11
268A 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
11
269Two 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
11
270Which 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
11
271Assertion
The ratio of inertial mass to
gravitational mass is equal to one.
Reason

The inertial mass and gravitational mass of a body are equivalent.
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. If Assertion is incorrect but Reason is correct

11
272A 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} )
11
273A 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 )
11
274A 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
11
275Consider the situation shown in the
figure. Calculate the acceleration of the
( 1.0 mathrm{kg} ) blocks
11
276A 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) )
11
277When 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)
11
278A 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 )
11
279Illustration 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
11
280Assertion
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
11
281The tension in the string is:
A. 600 N
B. 80 N
c. 1200 N
D. ( 800 mathrm{N} )
11
282A 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
283A 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 )
11
284The 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
11
285A 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?
A ( cdot 14 mathrm{ms}^{-1} )
В ( cdot 24 m s^{-1} )
( mathrm{c} cdot 31 mathrm{ms}^{-1} )
D. ( 190 mathrm{ms}^{-1} )

11
286From 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
11
287A 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
11
288If 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.
11
289The 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} )
11
290A 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
11
291A 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 )
11
292Assertion
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
293A canon after firing recoils due to newton’s third law of motion.
A . True
B. False
11
294Friction is a force that opposes motion.
A. True
B. False
c. Ambiguous
D. Data insufficient
11
295A 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} )
11
296Determine 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
11
297A 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
11
298Match 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.
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 )
11
299What is weight?11
300We 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?
11
301What do we call the gravitational force between the earth and an object?11
302A 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
11
303A 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 )
11
304An 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} )
11
305Block 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
11
306In 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
11
307Which 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
11
308surface 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
( mathbf{A} cdot N_{A}>N_{C}>N_{B} )
B . ( f_{A}>f_{C}>f_{B} )
( mathbf{c} cdot f_{C}>f_{A}=f_{B} )
D. ( N_{C}>N_{A}=N_{B} )

11
309A 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} )
11
310A streamlined body:
A. increases friction
B. reduces friction
C . decreases weight
D. increases weight
11
311A 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
11
312When 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
11
313A 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
11
314Unevenness 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
11
315When one body rolls over the surface of another body, which kind of friction
does it produce?
A. Static
B. Rolling
c. Fluid
D. sliding
11
316It 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
11
317The 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
11
318A 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 )
11
319Particles 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 )
11
320A 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
11
32138. 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
11
322A 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
11
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} )
11
324In 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
11
325A 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 )
11
326A good lubricant should be highly
A. viscous and volatile
B. non-viscous and non-volatile
c. viscous and non-volatile
D. transparent
11
friction.fill in the bank.
A. increase
B. decrease
c. neglect
D. overcome
11
328Two 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
11
329The 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} )
11
330A 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 )
11
331of 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
( 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 )
11
332A 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?
11
333A 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
11
334A 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
11
335A 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}} )
11
336The 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 )
11
337Abo
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
11
338When 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
11
339If 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.
11
340Block 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.
11
341Calculate 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
11
342If 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
11
343Which 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.
11
34425. 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
11
345What 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
11
346To 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} )
11
347A 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 )
11
348is 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
11
349A 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 )
11
350A 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} )
11
351heat is produced whenever work is done against friction
A. True
B. False
11
35220
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
11
353are 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} )
11
354Which 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
11
355A 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} )
11
356Illustration 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?
11
357A 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
11
358A 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
11
359wards, 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
11
360A 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} )
11
361Force is directly proportional to
A. Rate of change in distance
B. Rate of change in velocity
C. Momentum
D. Rate of change in momentum
11
362State whether true or false.
The linear momentum of a body at rest
is zero.
A. True
B. False
11
363Mark 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
11
364The 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
11
365A 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
11
366Inside 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
11
367A 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 )
11
368Three 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
11
369A 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
11
370Explain rocket propulsion.11
371A 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
11
372An 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
11
373What 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 )
11
374Identify 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.
11
375A 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
11
376A 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 )
11
377A 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{)} )
11
378A 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 )
11
379ration 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
11
380A 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} )
11
381The 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} )
11
382A 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
11
383A 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 )
11
384A 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 )
11
385You 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?
11
386A 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 )
11
387A 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 )
11
388Illustration 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
11
389toppr
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) )
11
390What 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
11
391A 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} )
11
39214 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
11
393A 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} )
11
394Illustration 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.
11
395A 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
11
396The 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
11
397Two 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 )
11
398Regarding 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
11
399Find 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
11
400If ( 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} )
11
401A 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) )
11
402Top 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
11
403Which 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
11
404A 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
11
405Starting 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
11
406A 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
11
407Which of the following quantities has equivalent units as Impulse?
A. Displacement
B. Velocity
c. Acceleration
D. Linear momentum
E. Kinetic energy
11
4082. 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)
11
409C. 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
11
410Find 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} )
11
411A 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 )
11
412State five differences between mass
and weight.
11
413State whether true or false.
Weight of a body remains constant anywhere in the universe.
A. True
B. False
11
414In 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
11
415Example 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?
11
416If 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?
11
417A 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
11
418When 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.
11
419A 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}} )
11
420A van is moving with a speed of 72 ( k m p h ) on a level road, where the
coefficient of friction between tyres and
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 )
11
421acceleration of mz is
ms-2
ms?
d. None of these
11
422How 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
11
42389. 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
11
424The 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
11
425If action is always equal to
reaction;explain
11
426A 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} )
11
427In 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.
11
428Assertion
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
11
42995. 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
11
430The 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
11
431State and explain the laws of limits friction.11
432Momentum is a measure of quantity of
A. motion
B. friction
c. gravitation
D. electric force
11
433A 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} )
11
434Angle between force and momentum
vectors in uniform circular motion is
A . ( 0^{circ} )
B. ( 30^{circ} )
( c cdot 45^{circ} )
D. ( 90^{circ} )
11
435Materials used to reduce friction are
called ( _{text {一一一一一一 }} ) (lubricants, beverages)
11
436Illustration 8.50 A particle of mass m is kept on a fixed,
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.
11
437If 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
11
438спе 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)
11
439Before burning the thread, what are the tensions in spring
a. m18,28
b. m 8, m 8-m28
c. m28, m 8
d. m 8,m,8 + m28
11
440Consider the situation shown in the
figure . The tension in the string connecting the 1.0 kg blocks.
11
44111. 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
11
442State whether given statement is True or False.
Force never exists in pairs.
A. True
B. False
11
443Assertion
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
11
444Two 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 )
11
445A 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
11
446methods 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
11
4479. 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
11
448If 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
11
449A 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
11
450Assuming 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
11
451Which 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””
11
452Assertion
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
11
453Illustration 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
11
454A 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) )
11
455The 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) )
11
456A 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?
11
457An 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 )
11
458Figure 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} )
11
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} )
11
460An 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 )
11
461A 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}} )
11
462If 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 % )
11
4635. 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.
11
464Give reasons for the following:
It is dangerous to get down from a moving bus even if the bus is moving slowly.
11
465Air resistance is also a form of friction.
A. True
B. False
11
466Illustration 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).
11
467Four 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} )
11
46820. The tension in the string attached to m is
a. 40 N b. 10 N c. 20 d. 5 N
11
469The 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 )
11
470Explain why objects moving in fluids must have special shapes.11
4711. 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,
11
472Two 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
11
473Mass 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
11
474Which 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
11
475A 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
11
476mall 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
11
4771. 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
11
478A 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} )
11
479Inertia of a body has direct dependence
on:
A. Velocity
B. Volume
c. Mass
D. Density
11
480Which of the following has more inertia
( ? )
A bicycle or a train
11
481Two 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
11
482Two 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} )
11
483External forces are always balanced State whether true or false.
A. True
B. False
11
484A 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 )
11
485In 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}} )
11
486Alida 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.
11
487Suppose your writing desk is titled a little. A book kept on it starts sliding
down. Show the direction of frictional
force acting on it.
11
488Which 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
11
489Calculate 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} )
11
490A 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
491toppr
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
11
492A 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 )
11
493Impulse 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} )
11
49424. 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
11
495A 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 )
11
496Maximum safe speed does not depend
upon
B. angle of inclination with the horizontal
c. mass of the vehicle
D. acceleration due to gravity
11
497The 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
11
498A 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 )
11
499A 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 )
11
500If circular race track is banked at angle
( theta(theta>text { angle of repose }), ) radius of track
is ( r ) and ( mu ) is coefficient of friction
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}
]
11
501Galilee’s law of inertia is another name
for newton’s (…) law of motion.
A. First
B. second
c. Third
D. Anyone of the above
11
502An astronaut in a space station orbits
above the Earth.

In the space station, the acceleration
due to gravity is ( 7.5 m / s^{2} ) On Earth, the acceleration due to gravity
is ( 10 m / s^{2} )
mass and weight in the space station is
correct?
A. Mass of astronaut – Same as on the Earth, weight of astronaut – less than on the Earth
B. Mass of astronaut – Same as on the Earth, weight of astronaut – greater than on the Earth
c. Mass of astronaut – lower than as on the Earth, weight of astronaut – less than on the Earth
D. Mass of astronaut – lower than as on the Earth, weight of astronaut – greater than on the Earth

11
503If 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 )
11
50410. 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
11
505A meteor burns up on entering earth’s atmosphere due to:
A. atmospheric pressure
B. heat of the earth
D. excessive friction
11
506the 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
11
507begin{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) )
11
508A ( 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) )
11
509Newton’s first law of motion is also
called Galileo’s law of:
A. Conservation of momentum
B. Inertia
c. Friction
D. conservation of mass
11
510A ( 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
11
511Which 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.
11
512According 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
11
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
11
514A 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} )
11
515Column 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.
11
516A 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} )
11
51717. 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
11
518The 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 )
11
519Which of the following physical quantities has the same units as that of impulse?
A. Momentum
B. Force
c. Torque
D. couple
11
520The 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
11
521Statement 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
11
522Consider 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
11
523Rolling friction varies with velocity. This
statement is :
A . True
B. False
11
524A 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} )
11
525In 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}} )
11
526A 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?
11
527Assertion
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
11
528After 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)} )
11
5299. 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:
11
5309. 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-
11
531Why 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
11
532A man weighing ( 1500 N ) exerts a
pressure of ( 105 N / m^{2} ) on the ground. Calculate his area of contact with the
ground.
11
533Figure 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).
11
534Newtons 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.
11
535A 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 )
11
536A 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 )
11
537Assertion
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
11
538A 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
11
539The 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} )
11
540Two 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 )
11
541If 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 )
11
542If ( 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
11
543Mark 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.
11
544A 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
11
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.
11
546A 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 )
11
5472. 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
11
548The 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} )
11
549An 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
11
550Two 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?
11
551Find 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
11
55254. 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
11
553There 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
11
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 )
11
555Assertion
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
11
5567. Maximum force Fo exerted by the bat on the bal.
a. 4000 N b. 5000 N c. 3000 N d. 2500
11
557State whether true or false.
Newton’s first law of motion gives the concept of momentum.
A. True
B. False
11
558Coefficients 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 )
11
559Fill 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
11
560In 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?
11
561in 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
11
56230. 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
11
563A 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} )
11
564State whether given statement is True or False.
Are forces acting on block actionreaction pair.
A. True
B. False
11
565Newton’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
11
566A 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 )
11
567If 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
11
568A 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?
11
569The 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
11
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} )
11
571A 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} )
11
572Choose 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 )
11
573In 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.
11
574In 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} )
11
575The 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
11
576Which 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
11
577A 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
11
57851. 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.
11
57910. The tension in the string is
a. 1.5mg b. 5.8mg
c. 4.7mg d. 3.2mg
11
580A 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.
11
581A 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?
11
582A 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 )
11
583A 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
11
584The 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
11
585Blocks 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} )
11
586The term ‘mass’ is analogous to physical quantity
A. Weight
B. Inertia
c. Force
D. Acceleration
11
587Choose 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
11
588A 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 )
11
5892. Just after burning the thread, what is the tension in the
spring?
a. m18 b. m28 c. Zero d. Cannot say
__
_
11
590If 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} )
11
591The 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} )
11
5926. 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
11
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
11
594Two ( 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 )
11
595During 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
11
596tration 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.
11
597A 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.
11
598The momentum of a massive object at
rest is
i) very large ii) very small iii) zero iv infinity
11
599Which 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
11
60012. 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
11
601A 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} )
11
602A 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} )
11
603If 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
11
604A 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
11
605What 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
11
606Mark 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
11
607A 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.
11
608A 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 )
11
60911. Acceleration of block C is
a. 1/4 ms2 b. 2/7 ms-2 c. 5/4 ms-2 d. 1/3 ms-2
11
610A 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
11
611L
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
11
61220
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
11
613A 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 )
11
614sliding 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.
11
615Which of the following statements is
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.
11
616A 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
11
6172. 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
11
6182 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
11
619A 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
11
620resting 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
11
621Momentum is a ( _{-}-_{-}-_{-}-_{-} ) quantity Fill in the blank.
A. scalar
B. vector
c. tensor
D. none
11
622Friction is a that opposite motion?
A. True
B. False
11
623State whether true or false.
Newton’s second law gives the measure of force.
A. True
B. False
11
624State and prove the law of conservation
of momentum.
11
625The 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
11
626v 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
11
627A 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
11
628A 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
11
629Assertion
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
11
630The 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
11
63113. 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
11
632The weight of 50 kg person at the surface of earth is
A . ( 50 N )
B. ( 35 N )
c. ( 380 N )
D. ( 490 N )
11
633A 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.
11
634Explain why sportsmen use shoes with spikes.11
635A 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
11
636An 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} )
11
637Assertion
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
11
638If 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} )
11
639A 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.
11
640State Newton’s third law of motion.11
641If a body is acted upon by a constant
force then it will have a uniform
A. velocity
B. acceleration
c. inertia
D. momentum
11
642Find 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
11
643A 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 )
11
644wheels
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
645A 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
11
646A ( 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?
11
647A 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} )
11
648S.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} )
11
64927. 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
11
651Two 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
11
652If 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
11
653A uniform solid cylinder is rolling down
a rough inclined plane of inclination ( boldsymbol{theta} )
Then?
11
654In 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
655A 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
656f 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
657A 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
658If 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
659Suppose 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
66090. 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
661Statement 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
662A 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
663The tension force between two block is:
A ( .10 N )
( B cdot frac{8}{3} N )
( c .8 N )
D. zero
11
664Three 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
665A 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
666limiting friction is slightly greater than friction.11
66755. 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
668The 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
669Ball bearings reduce friction because they – – – – rather than slide.
A . roll ( l )
B. swing
c. bounce
D. None of the above
11
670A 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
671A 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
672The maximum force of friction which
just allows one body to slide upon another body is called
11
673Which 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
674A 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
675A 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
67684. 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
677The 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
678An 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
679net 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
680The 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
68113 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
682A 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
683A 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
684Two 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
685The 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
686A 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
687Three 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
688In 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
689Explain why some of the leaves may get detached from a tree if we vigorously shake it branch.11
690In 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
691If 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
692Assertion
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
693A 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
69437°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
695A 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
696A 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
697A 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
698A 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
699A 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
700The force of friction always opposes
motion or the tendency of motion
A. True
B. False
11
701Object 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
703It 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
704Define Newton’s laws of motion.11
705th speed v against
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
706A 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
707Which Newton’s law of motion defines
force?
A. First
B. second
c. Third
D. None
11
708A 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
711A 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
712The 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
713A 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
714The 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
715In general, the relation between limiting
friction
rolling friction.
11
716Two 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
717Figure 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
718A 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
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
719Calculate 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
720The surface of the head of a match stick
and sides of a match box are
A. increase friction
B. decrease friction
c. increase amount of heat
D. decrease amount of heat
11
721A 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
722A 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
723A 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
724Two 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
725A 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
726Assertion
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
727A 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
728Fluid friction is exerted by
A. solids and liquids
B. solids and gases
c. liquids and gases
D. all the above
11
729A 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
730100. 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
731na
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
732When 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
733A 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
734Two 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
735Action and reaction
A. always act on two different bodies
B. are equal in magnitude
C . act in opposite directions
D. All the above
11
736Assertion
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
737In 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
738If 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
73945. Find the net tension force acting on the lower support.
a. Mg b. 2M2 c. 3Mg d. 4Mg
11
740Friction is much lesser in
in sliding.
11
741When 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
7423. 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
743If 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
744m
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
74541. 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
746In 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
747Assertion (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
748A car and a lorry are travelling with
same velocity on a straight horizontal road. Which of the two has got greater
momentum?
11
749A 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
750A 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
751Assertion
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
752Two 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
753In shown diagram, tension in the cord is
A. Zero
B. 25 N
( c cdot 50 N )
D. ( 100 mathrm{N} )
E. 200 N
11
754Three 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
755An 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
756A 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
757DO
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
758Two 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
759The mass of an object is a measure of inertia:
A. quantitative
B. qualitative
c. absolute
D. average
11
76067. 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
761Show that rate of change of
momentum = mass ltimes
acceleration.Under what condition does
this relation hold
11
762Who among the following anticipated Newton by declaring that all things gravitate to the earth?
A. Buddhagupta
B. Varahamihira
c. Aeyabhatta
D. Brahmagupta
11
763How 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
7651. 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
766Two 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
767MULP
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
768If 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
769The 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
770Pulun.
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
771A 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
772Why are ball bearings used in machinery?11
773toppr
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
77412. 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
775To 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
776Which will have least inertia?
( A ). A football
B. A needle
D. A refrigerator
11
777The 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
778A 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
779According 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
780A 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
78136. 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
782A 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
783Neglect friction. Find accelerations of
( m, 2 m ) and ( 3 m ) as shown in the figure.
The wedge (inclination ( =30^{circ} ) ) is fixed
11
784A 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
785Limiting 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
786Akhtar, 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
787The 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
788The 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
789Given 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
790A 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
791A 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
792Find the time period of disc?11
793Three 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
794UUU 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
795The friction between two bodies
produces
A. Motion
B. Expansion
c. Heat
D. None
11
796Two 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
797The 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
798What ways do you know to reduce
friction?
11
799A 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
80011. 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
80118. 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
802Classify 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
803Which 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
804A 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
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
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
806Every 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
807A 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
808A 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
809A 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
810A 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
811Frictional force is more between which
type of surfaces?
A. Smooth
B. Rough
c. Both A and B
D. None of the above
11
81238. Find the duration for which the force acts on the body.
a. 2s b. 3. c. 3.55 d. 4.55
11
813A 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
814connected 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
815A ( 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
816Every 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
817A ball is moving in the direction as
shown. What will be the direction of
momentum?
( A . W )
в. ( N )
( c . s )
D.
11
818If 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
819Two 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
820Physical 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
821Two 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
822Newton’s second law gives a measure of
A. Acceleration
B. Force
c. Momentum
D. Angular momentum
11
82342. 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
824The 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
825Which of the following material is likely to have least friction?
A. wood
c. glass
D. paper
11
826If 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
827In 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
828A 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
8295. 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
830Jahnvi 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
831The 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
832Calculate N and a11
833U. 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
834A 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
835A 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
83644. The extension produced in the spring is given by
a. 4Mg/K b. Mg/K c. 2Mg/K d. 3Mg/K
11
837A 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
838A ( 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
839An 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
840Newton’s law of motion were stated by
the scientist named as Charles-
Augustin
A. True
B. False
11
841Fluid friction depends on
A. speed of the object
B. shape of the object
c. nature of fluid
D. all of the above
11
842State and explain the law of inertia (or Newton’s first law of motion).11
843It 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
844A 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
845Four 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
846State whether true or false.
Self balancing toys have curved and heavy bases.
A. True
B. False
11
847A ( 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
848Driving a car on a highway with windows open reduce the speed. This is
due to:
A. air resistance
B. mechanical defect
D. none of these
11
849A 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
850An 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
851If 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
852A 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
853A 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
854If 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
855E
*
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
856Assertion
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
857A 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
858The 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
859To 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
860If 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
861Two 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
862What are the differences between the
mass of an object and its weight?
11
863ilustration 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
8643450
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
865To 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
866A 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
867A 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
869Consider 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
870A 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
871A 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
87228. 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
873When 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
874A 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
875If 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
876A 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
877The depressions and elevations present on the surface of objects causes
friction.
A. True
B. False
c. Ambiguous
D. Data insufficient
11
878A 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
879A 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
880A 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
881If 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
882State whether given statement is True or False.
A five rupees coin has more inertia
than a one-rupee coin.
A. True
B. False
11
883It 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
884A 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
885A 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
886Which 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
887A 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
888Consider 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
890A 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
891A 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
892Name 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
893Frictional force always opposes:
A. The state of rest
B. The state of motion
c. None of the above
D. Both the states
11
894Which 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
895A 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
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
8973. 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
898A 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
899What 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
900e pulley of the system shown in Fig.
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
901limiting friction is of the area of
contact.fill in the blank
A. directly proportional
B. indirectly proportional
c. independent
D. none
11
902Who proposed the concept of Inertia?
A. Gallileo
B. Newton
c. Pascal
D. Einstein
11
90344. 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
904Find 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
905If 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
906The 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
907A 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
908Rocket works on the principle of conservation of:
A. Mass
B. Energy
c. Momentum
D. Velocity
11
909An 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
910A 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
911After 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
912Velocity 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
91313. 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
914A 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
915In 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
916Three 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
917A 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
918The friction that exists between a
surface sliding over another is called
11
919A 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
920A 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
A. Normal force applied by cylinder on rod at ( A ) is ( 3 m g / 2 )
B. Normal force applied by cylinder on rod at ( B ) must be zero
C. Friction force acting on rod at ( B ) is upward
D. Normal force applied by cylinder on rod at ( A ) is ( mathrm{mg} )

11
921When 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
922Mark 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} )
during the third second of its fall.

11
923Which 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
924Define the darg?11
925A 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
92616. 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
927A 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
928Student ( 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
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
930A 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
931Assertion
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
932Momentum is a measure of
A. Weight
B. Mass
C . Quantity of motion
D. Velocity
11
933What is momentum? Write its SI unit.
Interpret force in terms of momentum
Represent the following graphically.
11
934force 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
935The 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
936A 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
937The 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
938A 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
939Illustration 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
940Idea 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
11
941Assertion
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
11
942A 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 )
11
943A 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 )
11
944The property of inertia is more in:
( A cdot ) a car
B. a truck
( c . ) a cart
D. a toy car
11
945A 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
11
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 )
11
947Five 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
11
948Assertio
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
11
9499. 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
11
95035. 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.
11
951Assertion
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
11
952A 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} )
11
953Which 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””
11
954A 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}} )
11
955A 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.
11
956A 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
957If 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 false11
958From 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.
11
959A 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} )
11
960A 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
11
961A 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
962An 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}) )
11
963A 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.
11
964To 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
11
965For 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} )
11
966The depressions and elevations present on the surface of objects causes
friction.
A. True
B. False
11
967A 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
11
968U. 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
11
969A 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 ).
11
970A 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 )
11
971Normal force is a
A. Action force
B. Reaction force
c. Both
D. None
11
972When you walk or run you push your foot ( _{text {一一一一一一一一 }} ) (forwards, backwards)11
973A 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
11
974A 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 )
11
975Assertion
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
value of safe limit velocity.
A. If both Assertion and Reason are correct and Reason the correct explanation of the Assertion
B. If both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion
c. If Assertion is true but Reason is false
D. If Assertion is false but Reason is true

11
976Banking 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
11
977A 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
11
97817. 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
11
979A 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
11
980A 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.
11
9812. 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
11
982A 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
11
983You 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
11
984List 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} )
( A cdot a-f, b-g, c-h, d-e )
B. a-g, b-f, c-e, d-h
c. a-h, b-e, c-f, d-g
D. a-e

11
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
11
986The 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
11
987Which 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.
11
98818. 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.
11
989Unu 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
11
990A 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 )
11
991A 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
11
992Which of the following material is likely to have least friction?
A. woodd
B. Plasticç
c. Glass
D. Paper
11
99318. 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
11
994In 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
995In 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.
11
996When 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
997A 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
998You 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
11
999Friction 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
1000What 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.
11
1001A 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}} )
11
1002Statement 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
11
1003A 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}} )
11
1004A 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} )
11
1005An 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
11
1006A 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 )
11
1007Find 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 )
11
1008A ( 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?
11
1009At 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
1010An 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
11
1011The 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
11
101245. 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
11
1013Which 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
11
1014Assertion
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
11
1015limiting value of static friction is sliding friction.
A. less than
B. equal to
c. more than
D. less than or equal to
11
101675. 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
1018The 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
11
1019Though friction can provide necessary centripetal force, the banking of roads is considered as advantageous in
highways:
A . True
B. False
11
1020A 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.
11
1021If 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
1022Fig 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 )
11
102329. 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
1024Light 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
1025Two 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.
11
1026Two 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}} )
11
1027Fill in the blank.
Water offers fluid friction as
compared to honey.
A. higher
B. lower
c. same
D. zero
11
1028When 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
11
1029Student ( 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
11
1030A 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
1031When a running horse suddenly stops, the rider falls forwards.
A. True
B. False
11
1032Physical 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
1033n 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
1034Assertion
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
1035A 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
1036Give reasons
A heavy truck is filled with 6 to 14 wheels.
11
1037A 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
1038Identify which of the following quantity describe object’s resistance to change
in motion.
A. acceleration
B. velocity
c. mechanics
D. force
E. inertia
11
103948. 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
1040A 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
1041A 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
1042The 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
1043There 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
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
1045How 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
1046A 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
1047Assertion
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
1048Illustration 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
( 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
1050A 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
1051State whether the given statement is true or false :
Friction is a necessary evil.
A. True
B. False
11
1052A 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
1053A 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
1054The 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
1055Find 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
1056A 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
1057When two surfaces are polished, the friction coefficient between them
decreases. But the friction coefficient
increases and becomes very large if the
Explain.
11
1058Impulse 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
1059A 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
1060A 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
1061A 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
10623. 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
1063Two 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
1064Show that Newton’s third law of motion
is contained in his second law.
State and explain the principle of conservation of angular momentum
11
1065China 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
1066Which 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
1067When 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
1068riy. 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
1069A 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
1070Assertion
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
1071A 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
1072Which 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
1073The 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
1074To 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
1075A 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
10773. 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
1078Illustration 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
1079A 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
1080Explain the mechanism behind Motion
of a Rocket.
11
1081The efficiency of machine is reduced due to friction.
A. True
B. False
c. Ambiguous
D. Data insufficient
11
1082A ( 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
1083An 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
1084A 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
1085The 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
1086Two 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
1087Example 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
1088Iwo 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
11
1089Aeroplanes are streamlined to reduce:
A. fluid friction
B. sliding friction.
c. kinetic friction
D. limiting friction.
11
1090limiting friction is also celled as11
1091A 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
1092A 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
10937. 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
1094An 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
1095Greater the mass, greater is the inertia of the body. Type 1 for true and 0 for false11
1096The 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
1097A 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
1098A 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
1099Friction 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
1100State whether given statement is True or False.
Linear momentum is always in the direction of velocity
A. True
B. False
11
1101When 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
1102A 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
1103Two 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
1104The 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
1105A 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
11067. 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
1107Which has a greater momentum, an
elephant at rest or an ant in motion?
A. Elephant
B. Ant
c. Neither has momentum
D. Same
11
1108Assertion
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
1109Illustration 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
11101. 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
1111A 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
1112Assertion
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
1113The force of friction is
normal reaction between the surfaces.
11
1114A 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
1115Two 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
111623. 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
1117A 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
1118A 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
1119A 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
A. Magnetic Force
B. Electrostatic Force
C. Frictional Force
D. All
11
1121A 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
1122Mention three methods of reducing friction in a machine11
1123Which will have move inertia?
A. A plastic eraser
B. Pencil
( c ). A book
D. A table
11
1124Ulustration 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
1125Even through the magnitudes at action
force and reaction force are equal and
their direction are opposite, their effects do not get cancelled,
11
1126A 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
1127Graphite powder is used in machines to
A. Enhance friction
B. Enhance profit
c. Reduce friction
D. Reduce efficiency
11
1128A 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
1129A 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
1130State newton’s second law of motion
and give related expression why does a cricket player lower his hands while catching the ball?
11
1131Find 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
1132Is larger surface area break on a bicycle wheel more effective than small surface
area brake? Explain?
11
1133Illustration 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
1134By a bullet fire by a gun is more dangerous then bullet fire with medium
speed? Explain it properly
11
1135A 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
1136Two 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
1137Define Friction:11
1138Friction 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
1139A 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
1140A 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
1141A 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
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
1142Galileo’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
1143The 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
1144A 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
1145A 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
1146Kumaran 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
1147topp
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
1148TUU 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
1149A ( 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
1150A 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
1151Differentiate between mass and weight.11
1152A 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
115319. 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
1154A 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
115514. 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
1156A 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
1157A 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
1158A 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
1159Mass( times )velocity( = )
A. Impulse
B. Momentum
c. Area
D. Force
11
1160A ( 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
1161State whether given statement is True or False.

You fall in the forward direction when a
moving bus applies brakes to stop, and fall backward when it accelerates from
rest.
A. True
B. False

11
1162A 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
1163The 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
1164Powder is used in carrom board for:
A. Increasing friction
B. Decreasing friction
c. Decoration
D. None of the above
11
1165TIJU. 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
1166What 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
1167Rocket propulsion works on the
principle of:
A. Newtons laws of motion
B. Faradays laws of electromagnetic induction
C. Laws of thermodynamics
D. Archimedes
11
1168If the normal reactional force is
doubled, the coefficient of friction is :
A. doubled
B. halved
c. not charged
D. tripled
11
1169Two 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
1170The 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
1171A ( 1500 k g ) car is initially moving with
speed ( 30 m / s . ) Suddenly, a rock falls

The maximum coefficient of friction
between the car tires and the roads is
( mu=0.7 )
Approximately how much distance will the car need to stop to avoid hitting the rock?
( mathbf{A} cdot 22 m )
B. ( 46 m )
c. ( 66 m )
D. ( 87 m )
E . ( 131 m )

11
1172Frictional 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
1173tllustration 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
1174A 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
1175mas 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
1176Assertion
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
1177If earth attracts an apple with a force of
10 newton, then with what force the
apple will attract the earth.
11
1178An 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
1179A 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
1180Two 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
1181When a bicycle travels on a rough surface, its speed,
A. increases
B. decreases
c. remains the same
D. none of these
11
1182The 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
1183State whether True or False:
A man slip when he steps on a
banana peel thrown on the road.
11
1184Force 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
1185The substance that helps to friction are called lubricants.
A. increase
B. decrease
c. create
D. eliminate
11
1186Four 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
1187With increase of temperature, the frictional force acting between two
surfaces increases.
A. True
B. False
c. Ambiguous
D. Data Insufficient
11
1188Why is friction greater between rough surfaces than between smooth ones?11
1189A 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
1190Hailstones falling from atmosphere relates to:
A. static friction
B. rolling friction
c. sliding friction
D. fluid friction
11
1191Wheel reduce friction due to.
A. more area of contact
B. less area of contact
( c cdot operatorname{size} )
D. all of the above
11
1192A 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
1193Which 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
1194A 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
1195A boat is streamlined to reduce the
resistance to motion offered by water
A. True
B. False
11
1196To 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
1197Water 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
11986. 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
1199A ( 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
1200Which 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
1201Two 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
1202Why is it advised to tie any luggage kept on the roof of a bus with a rope?11
1203A 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
1204A ( 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
1205A 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
1206Three 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
1207A 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
1208Blocks 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
1209Suppose 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
1210A 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
1211Which 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
1212The time at which block will leave the
inclined plane is?
A . 1 s
B . 2 s
( c cdot 3 s )
D. 4 s
11
1213The 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
1214A 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
1215A 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
1216What is the force acting on the
connecting bar?
A . ( 150 mathrm{N} )
B. 100 N
( c .75 mathrm{N} )
D. 125 N
11
1217topp
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
1218Keeping 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
1219A 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
1220In 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
1221A 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
1222Two 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
1223The 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
122411. 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
12255. 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
1226Powder is a lubricant
A. True
B. False
c. None
D. Can’t say
11
1227Eleven 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
1228One 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
1229SS
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
1230The 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
1231The 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
1232A 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
1233Illustration 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
1235Which 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
1236A 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
1237Which 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
1238A 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
1239A 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
124015. 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
1241A ( 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
1242A 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
12431. 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
1244The 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
1245The 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
which the system should be moved to the right so that suspended blocks ( A ) (mass ( m ) ) and ( B(text { mass } M text { and } N>m) )
can remain stationary relative to ( C )

11
1246Action and reaction force acts on:
A. same body
B. different bodies
c. lower body
D. upper body
11
1247on wow
( F )
11
1248Statement 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
1249In 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
1251While 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
1252Assertion
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
1253State whether the given statement is
true or false :

A horse continues to apply a force in
order to move a cart with a constant
speed.
A. True
B. False

11
1254What 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
1255A 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
1256The friction coefficient between the
table and the block shown in the figure is 0.2 . Find the tensions in the two
strings.
11
12574. 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
1258A 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
1259A 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
1262A 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
1263Water sprinkler used for grass lawns
begins to rotate as soon as the water is supplied. It is based on which law?
11
1264The 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
126572. 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
12665. 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
1267A 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
1268A 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
1269If 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
1270Assertion
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
1271A 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
1272Match 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
127382. 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
1274A 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
1275TUMU 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
1276Relation 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
1277A 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
1278The 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
1279A 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
1280What 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
1281State whether true or false.
A cone resting on its side is an example of a body in neutral equilibrium.
A. True
B. False
11
1282Newton’s first law of motion leads to the
concept of
( A cdot ) force
B. inertia
c. both of the above
D. temperature
11
1283A 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
1284A 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
1285A 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
1286What is fluid friction?11
128719. 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
11
1288If ( 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
1289Assertion
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
1290Tllustration 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
1291tilustration 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
129246. 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
1293A 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
1294A 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
1295In 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
1296A 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
1297Two 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
1298You 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
1299ween 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
1300Two 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
1301Is force needed to keep a moving body in motion? Which one of the Newton’s laws
A. No, first law
B. Yes, third law
c. No, second law
D. Yes, first law.
11
1302The 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
1303A 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
1304If ( 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
1305A 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
1306The 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
1307Consider 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
13082. 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
130915. 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
1310A 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
1311Assertion
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
1312Illustration 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
1313The 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
1314A 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
1315The 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
1316State whether the statements are true
or false-

Frictional force is a non-contact force.
A. True
B. False

11
1317A 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
1318ply. 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
1319When 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
1320VU
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
1321Two 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
1322Automobile tyres have generally irregular projections over their surfaces.Why?11
1323Rank 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
1324A 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
1325A 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
1326Inertia means resistance to the change
of state.
A . True
B. False
11
132798. 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
1328Our 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
1329Two 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
1330The weight of a freely falling body is always constant.
A . True
B. False
11
1331An 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
1332Newton’s law of motion were published
in the year 1699
A . True
B. False
11
1333MTN2
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
1334A 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
1335The rate of change of linear momentum of a body falling freely under gravity is equal to it’s11
1336The 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
133746. 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
1338The weight of body can be zero. True or false.
A . True
B. False
11
1339A 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
1340An 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
1341A 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
1342Write the approximate weight of a body
of mass ( 5 k g ? )
B. ( 5 N )
c. ( 0.5 N )
D. ( 50000 N )
11
1343A 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
13443. 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
1345A 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
1346Displacement 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
13475 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
1348A 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
1349A 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
1350A 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
1351The 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
1352A 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
1353A 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
1354According 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
1355A 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
1356An 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
1357What 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{)} \
sqrt{w}+r \
end{array}
end{array}
]
11
1358A 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
1359Which 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
136010. 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
1361If 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
1362A 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
1363n 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
1364A 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
1365A 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
1366A 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
1367What effect will it have on the motion of
the body if it is made to move on a
sandy surface?
11
1368A 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
1369A 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
1370Two 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
1371Suppose 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
1372A 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
1373The maximum value of static friction is
called limiting friction.
A. True
B. False
c. Ambiguous
D. Data insufficient
11
1374A 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
1375Three 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
1376A 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
1377Find 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
1378Two 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
1379A 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
138024. The acceleration of m, is
-ms-2
ms-2
20 ms²
d. 178 ms ²
11
1381A 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
1382A 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
1383Assertion
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
1384Change in the state of rest or of uniform motion is brought about by:
A. Acceleration
B. Force
c. Energy
D. None
11
1385A 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
1386A 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
1387A 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
1388Assertion
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
1389A 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
1390A 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
1391A 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
1392In 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
1394Which 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
1395Passengers 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
1396A 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
1397A 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
1398Figure 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
1399State whether given statement is True
or False.

The actual force applied by the brakes may be slightly less than the calculated
value.
A. True
B. False

11
1400Suppose gravity of earth suddenly becomes zero, then in which direction
will the moon begin to move if no other
celestial body affects it?
B. Tangential
c. cant say
D. None
11
1401Can a body have energy without having momentum ? Explain?11
1402The 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
1403A 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
1404If ( 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
14056. 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
1406A 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
14081d 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
1410If 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
1411A 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
1412What 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
1413According 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
1414Consider 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
1415Why 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
1416A ( 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
1417A 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 )
11
141812 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
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
11
1419A 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 )
11
1420ritustration 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
11
1421A 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} )
11
1422A 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?
11
1423A 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} )
11
1424A 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.
11
1425Consider 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) )
11
1426Two 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?
11
1427Which 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
11
1428A 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?
11
1429A 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
11
1430Two 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}} )
11
1431Friction is a type of:
A. resistance force
B. non contact force
c. contact force
D. motion
11
1432Assuming 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} )
11
1433With increase of temperature, the frictional force acting between two surfaces:
A . increases
B. decreases
c. remains same
D. may increases or decreases
11
14340. 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
11
1435A 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
11
1436In 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
11
1437wedge 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
11
143832. 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
Fig. 6.317
a. 1.5 ms- b. 3 ms-1 c. 6ms-1 d. 4.5 ms-1
11
1439A 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 )
11
1440A 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} )
11
1441Consider 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
11
1442Which 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
11
1443A 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
11
1444A 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} )
11
1445A 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}} )
11
1446A 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
11
1447Suppose 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} )
11
1448Find 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} )
11
1449If 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
11
1450In 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
11
1451Friction is ( quad ) in some situations.
A. desirable
B. undesirable
c. both ( A ) and ( B )
D. none of the above
11
1452A 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 )
11
1453A 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
11
1454Free body diagrams doesn’t play any role in making the calculations on the conditions of the equilibrium of the body.
A . True
B. False
11
14552. 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
11
1456Three 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
11
1457A 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 )
11
1458A 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 )
11
1459An 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.
11
1460Radius 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} )
11
1461What is the momentum versus velocity graph is like, when mass is fixed?
A. Straight line
B. Exponential curve
c. Parabola
D. circle
11