# MCQs For NCERT Class 11 Physics Chapter 7 Systems Of Particles And Rotational Motion

Please refer to the MCQ Questions for Class 11 Physics Chapter 2 Systems Of Particles And Rotational Motion with Answers. The following Systems Of Particles And Rotational Motion Class 11 Physics MCQ Questions have been designed based on the latest syllabus and examination pattern for Class 11. Our experts have designed MCQ Questions for Class 11 Physics with Answers for all chapters in your NCERT Class 11 Physics book.

## Systems Of Particles And Rotational Motion Class 11 MCQ Questions with Answers

See below Systems Of Particles And Rotational Motion Class 11 Physics MCQ Questions, solve the questions and compare your answers with the solutions provided below.

Question. A solid cylinder of mass 3 kg is rolling on a horizontal surface with velocity 4 m s–1. It collides with a horizontal spring of force constant 200 N m–1. The maximum compression produced in the spring will be
(a) 0.5 m
(b) 0.6 m
(c) 0.7 m
(d) 0.2 m

B

Question. A solid cylinder and a hollow cylinder, both of the same mass and same external diameter are released from the same height at the same time on an inclined plane. Both roll down without slipping. Which one will reach the bottom first?
(a) Both together only when angle of inclination of plane is 45°.
(b) Both together.
(c) Hollow cylinder.
(d) Solid cylinder.

D

Question. A drum of radius R and mass M, rolls down without slipping along an inclined plane of angle q. The frictional force
(a) dissipates energy as heat
(b) decreases the rotational motion
(c) decreases the rotational and translational motion
(d) converts translational energy to rotational energy.

D

Question. A solid sphere of radius R is placed on a smooth horizontal surface. A horizontal force F is applied at height h from the lowest point. For the maximum acceleration of centre of mass, which is correct?
(a) h = R
(b) h = 2R
(c) h = 0
(d) no relation between h and R.

D

Question. A disc is rolling, the velocity of its centre of mass is vcm. Which one will be correct?
(a) The velocity of highest point is 2 vcm and at point of contact is zero.
(b) The velocity of highest point is vcm and at point of contact is vcm.
(c) The velocity of highest point is 2vcm and point of contact is vcm.
(d) The velocity of highest point is 2vcm and point of contact is 2vcm.

A

Question. A solid spherical ball rolls on a table. Ratio of its rotational kinetic energy to total kinetic energy is
(a) 1/2
(b) 1/6
(c) 7/10
(d) 2/7

D

Question. A solid sphere, disc and solid cylinder all of the same mass and radius are allowed to roll down (from rest) on the inclined plane, then
(a) solid sphere reaches the bottom first
(b) solid sphere reaches the bottom last
(c) disc will reach the bottom first
(d) all reach the bottom at the same time.

A

Question. Centre of mass of the earth and the moon system lies
(a) closer to the earth
(b) closer to the moon
(c) at the mid-point of line joining the earth and the moon
(d) cannot be predicted

A

Question. Moment of inertia does not depend upon
(a) distribution of mass
(b) axis of rotation
(c) point of application of force
(d) None of these

C

Question. A disc is given a linear velocity on a rough horizontal surface then its angular momentum is
(b) conserved about the point of contact only
(c) conserved about all the points
(d) not conserved about any point.

B

Question. A body cannot roll without slipping on a
(a) rough horizontal surface
(b) smooth horizontal surface
(c) rough inclined surface
(d) smooth inclined surface

D

Question. A body is projected from ground with some angle to the horizontal. The angular momentum about the initial position will
(a) decrease
(b) increase
(c) remains same
(d) first increase then decrease

B

Question. A ball tied to a string is swung in a vertical circle. Which of the following remains constant?
(a) tension in the string
(b) speed of the ball
(c) centripetal force
(d) earth’s pull on the ball

D

Question. Angular momentum of a system of a particles changes,when
(a) force acts on a body
(b) torque acts on a body
(c) direction of velocity changes
(d) None of these

B

Question. Angular momentum is
(a) a polar vector
(b) an axial vector
(c) a scalar
(d) None of these

B

Question. If a running boy jumps on a rotating table, which of thefollowing is conserved?
(a) Linear momentum
(b) K.E
(c) Angular momentum
(d) None of these

C

Question. A gymnast takes turns with her arms & legs stretched. When she pulls her arms & legs in
(a) the angular velocity decreases
(b) the moment of inertia decreases
(c) the angular velocity stays constant
(d) the angular momentum increases

B

Question. Moment of inertia of a circular wire of mass M and radius R about its diameter is
(a) MR2/2
(b) MR2
(c) 2MR2
(d) MR2/4.

A

Question. A particle is confined to rotate in a circular path decreasing linear speed, then which of the following is correct?
(a) L (angular momentum) is conserved about the centre
(b) only direction of angular momentum L is conserved
(c) It spirals towards the centre
(d) its acceleration is towards the centre.

B

Question. Two rings of radius R and nR made up of same material have the ratio of moment of inertia about an axis passing through centre as 1 : 8. The value of n is
(a) 2
(b) 2 √2
(c) 4
(d) 1/2

A

Question. In carbon monoxide molecule, the carbon and the oxygen atoms are separated by a distance 1.12 × 10–10 m. The distance of the centre of mass, from the carbon atom is
(a) 0.64 × 10–10 m
(b) 0.56 × 10–10 m
(c) 0.51 × 10–10 m
(d) 0.48 × 10–10 m

A

Question. A solid sphere is rotating in free space. If the radius of the sphere is increased keeping mass same which one of the following will not be affected ?
(a) Angular velocity
(b) Angular momentum
(c) Moment of inertia
(d) Rotational kinetic energy

B

Question. Angular momentum is
(a) moment of momentum
(b) product of mass and angular velocity
(c) product of M.I. and velocity
(d) moment of angular motion

A

Question. The angular momentum of a system of particle is conserved
(a) when no external force acts upon the system
(b) when no external torque acts upon the system
(c) when no external impulse acts upon the system
(d) when axis of rotation remains same

B

Question. Analogue of mass in rotational motion is
(a) moment of inertia
(b) angular momentum
(c) gyration
(d) None of these

A

Question. Moment of inertia does not depend upon
(a) angular velocity of body
(b) shape and size
(c) mass
(d) position of axis of rotation

A

Question.The centre of gravity of the sphere with the sand
(a) rises continuously
(b) remains unchanged in the process
(c) First rises and then falls to the original position
(d) First falls and then rises to the original position

D

Question. A solid sphere and a hollow sphere of the same material and of same size can be distinguished without weighing
(a) by determining their moments of inertia about their coaxial axes
(b) by rolling them simultaneously on an inclined plane
(c) by rotating them about a common axis of rotation
(d) by applying equal torque on them

B

Question. A flywheel rotates about an axis. Due to friction at the axis, it experiences an angular retardation proportional to its angular velocity. If its angular velocity falls to half while it makes n rotations, how many more rotations will it make before coming to rest?
(a) 2n
(b) n
(c) n/2
(d) n/3

B

Question. A raw egg and a hard boiled egg are made to spin on a table with the same angular momentum about the same axis. The ratio of the time taken by the two to stop is
(a) = 1
(b) < 1
(c) > 1
(d) None of these

B

Question. A solid cylinder of mass 20 kg rotates about its axis with angular speed 100 rad/s. The radius of the cylinder is 0.25 m. The K.E. associated with the rotation of the cylinder is
(a) 3025 J
(b) 3225 J
(c) 3250 J
(d) 3125 J

D

Question. A tube one metre long is filled with liquid of mass 1 kg. The tube is closed at both the ends and is revolved about one end in a horizontal plane at 2 rev/s. The force experienced by the lid at the other end is
(a) 4p2N
(b) 8p2N
(c) 16p2N
(d) 9.8 N

B

Question. If the linear density (mass per unit length) of a rod of length 3m is proportional to x, where x is the distance from one end of the rod, the distance of the centre of gravity of the rod
from this end is
(a) 2.5 m
(b) 1 m
(c) 1.5 m
(d) 2 m

D

Question. A composite disc is to be made using equal masses of aluminium and iron so that it has as high a moment of inertia as possible. This is possible when
(a) the surfaces of the disc are made of iron with aluminium inside
(b) the whole of aluminium is kept in the core and the iron at the outer rim of the disc
(c) the whole of the iron is kept in the core and the aluminium at the outer rim of the disc
(d) the whole disc is made with thin alternate sheets of iron and aluminium

B

Question. Two particles A and B, initially at rest, moves towards each other under a mutual force of attraction. At the instant when the speed of A is v and the speed of B is 2 v, the speed of centre of mass is
(a) zero
(b) v
(c) 1.5 v
(d) 3 v

A

Question. Point masses 1, 2, 3 and 4 kg are lying at the points (0, 0, 0),(2, 0, 0), (0, 3, 0) and (–2, –2, 0) respectively. The moment of inertia of this system about X-axis will be
(a) 43 kg –m2
(b) 34 kg–m2
(c) 27 kg – m2
(d) 72 kg – m2

A

Question. A body having moment of inertia about its axis of rotation equal to 3 kg-m2 is rotating with angular velocity equal to 3 rad/s. Kinetic energy of this rotating body is the same as that of a body of mass 27 kg moving with a speed of
(a) 1.0 m/s
(b) 0.5 m/s
(c) 1.5 m/s
(d) 2.0 m/s

A

Question. A particle moves in a circle of radius 0.25 m at two revolutions per second. The acceleration of the particle in metre per second2 is
(a) p2
(b) 8p2
(c) 4p2
(d) 2p2

C

Question. The radius of gyration of a body about an axis at a distance 6 cm from its centre of mass is 10 cm. Then, its radius of gyration about a parallel axis through its centre of mass will be
(a) 80 cm
(b) 8 cm
(c) 0.8 cm
(d) 80 m

B

Question. A particle of mass m is moving in a plane along a circular path of radius r. Its angular momentum about the axis of rotation is L. The centripetal force acting on the particle is
(a) L2 /mr
(b) L2 m/r
(c) L2 /m r3
(d) L2 /m r2

C

Question. A small disc of radius 2 cm is cut from a disc of radius 6 cm. If the distance between their centres is 3.2 cm, what is the shift in the centre of mass of the disc?
(a) 0.4 cm
(b) 2.4 cm
(c) 1.8 cm
(d) 1.2 cm

A

Question. The ratio of moment of inertia of circular ring & circular disc having the same mass & radii about on axis passing the c.m & perpendicular to plane is
(a) 1 : 1
(b) 2 : 1
(c) 1 : 2
(d) 4 : 1

B

Question. A rod of length L is pivoted at one end and is rotated with a uniform angular velocity in a horizontal plane. Let T1and T2 be the tensions at the points L/4 and 3L/4 away from the pivoted end. Then
(a) T1 > T2
(b) T2 > T1
(c) T1 – T2
(d) the relation between T1 and T2 depends on whether the rod rotates clockwise and anticlockwise.

A

Question. A particle of mass m is observed from an inertial frame of reference and is found to move in a circle of radius r with a uniform speed v. The centrifugal force on it is
(a) mv2 /r towards the centre
(b) mv2 /r away from the centre
(c) mv2 /r along the tangent through the particle
(d) zero

D

Question. A particles performing uniform circular motion. Its angular frequency is doubled and its kinetic energy halved, then the new angular momentum is
(a) L/4
(b) 2 L
(c) 4 L
(d) L /2

A

Question. A couple is acting on a two particle systems. The resultant motion will be
(a) purely rotational motion
(b) purely linear motion
(c) both a and b
(d) None of these

A

Question. A mass m is moving with a constant velocity along a line parallel to the x-axis, away from the origin. Its angular momentum with respect to the origin
(a) is zero
(b) remains constant
(c) goes on increasing
(d) goes on decreasing.

B

Question. A smooth sphere A is moving on a frictionless horizontal plane with angular speed w and centre of mass velocity v. It collides elastically and head on with an identical sphere B at rest. Neglect friction everywhere. After the collision, their angular speeds are wA and wB, respectively. Then
(a) wA< wB
(b) wA= wB
(c) wA= w
(d) wB= w

C

Question. A weightless ladder 20 ft long rests against a frictionless wall at an angle of 60º from the horizontal. A 150 pound man is 4 ft from the top of the ladder. A horizontal force is needed to keep it from slipping. Choose the correct magnitude from  the following.
(a) 175 lb
(b) 100 lb
(c) 120 lb
(d) 17.3 lb