• Amal Augustine
• December 20, 2025

Centre of Mass and Rotational Motion MCQs – Elite Conceptual Physics Practice

The topic of centre of mass and rotational motion MCQs plays a crucial role in developing a deep understanding of system dynamics, rigid body motion, and angular kinematics.Centre of mass and rotational motion mcqs questions from this chapter test how mass distribution affects motion, how internal and external forces influence systems, and how linear motion transitions into rotational behavior.

Centre of mass and rotational motion MCQs often test how translational and rotational behaviors of a system are interconnected. While the centre of mass describes the average position of mass in a system and governs its overall motion, rotational motion focuses on how different parts of the body move around an axis.Centre of mass and rotational motion  MCQs combine these ideas by asking how external forces affect the centre of mass without altering rotational motion, or how torque causes rotation without changing the motion of the centre of mass.

In competitive exams like NEET, JEE, and board examinations,  centre of mass and rotational motion mcqs often emphasize conceptual reasoning, symmetry, conservation laws, and angular variables rather than lengthy calculations. Practicing such centre of mass and rotational motion MCQs helps aspirants clearly visualize physical systems such as rotating discs, circular tracks, celestial bodies, and multi-particle systems.

Centre of Mass and Rotational Motion  MCQs-

1. The centre of mass of an extended body on Earth coincides with its centre of gravity when
A. Never
B. Size of body is negligible compared to Earth
C. Always
D. Only for spherical bodies
Answer: B

2. Masses m, 2m, and 3m are at (0,0), (1,0), and (–2,0). X-coordinate of COM is
A. 1/3
B. 2/3
C. –1/3
D. –2/3
Answer: D

3. The sum of moments of all particles about the centre of mass is always
A. Minimum
B. Zero
C. Maximum
D. Infinite
Answer: B

4. The centre of mass of a ring is located
A. At centre, outside material
B. Inside material
C. On circumference
D. Along tangent
Answer: A

5. For two masses m and M (M > m), the centre of mass lies
A. Towards m
B. Towards M
C. At midpoint
D. At m
Answer: B

6. Centre of mass is the point
A. Geometric centre
B. Origin of reference frame
C. Where total mass is assumed concentrated
D. Equidistant from all particles
Answer: C

7. A 10 kg mass placed at Earth’s centre has weight
A. 98 N
B. 98 kg
C. 49 N
D. 0 N
Answer: A

8. In Earth–Moon system, the periods of revolution about their COM satisfy
A. T₁ = T₂
B. T₁ < T₂
C. T₁ > T₂
D. Cannot be compared
Answer: B

9. Centre of mass of a half-ring of radius 0.5 m from its centre is
A. π/1
B. 2/1
C. π/3
D. 2π/1
Answer: A

10. Two particles move toward each other with speeds v and 2v. Speed of COM is
A. Zero
B. v
C. 3v/2
D. –3v/2
Answer: A

11. If resultant external force on a system is zero, the centre of mass
A. Moves with constant velocity
B. Accelerates
C. Remains fixed
D. Moves randomly
Answer: A

12. Two particles attract each other under inverse square law. The COM
A. Moves toward heavier mass
B. Moves toward lighter mass
C. Remains at rest
D. Accelerates
Answer: C

13. Cheetah (150 kg, 20 m/s) chasing deer (30 kg, 25 m/s). COM speed ≈
A. 21 m/s
B. 26 m/s
C. 24 m/s
D. 20 m/s
Answer: A

14. Particles placed symmetrically around origin at distance R have COM
A. < R
B. > R
C. = R
D. Undefined
Answer: B

15. Filling a hollow pendulum bob with sand shifts COM
A. Randomly
B. Downwards only
C. Upwards only
D. First down then up
Answer: D

16. Centre of mass of a body may lie
A. Always outside
B. Inside, outside, or on surface
C. Always inside
D. Only on surface
Answer: B

17. A bomb explodes mid-air; COM of fragments follows
A. Vertical line
B. Straight downward
C. Irregular path
D. Same parabolic path
Answer: D

18. Correct statements about COM
A. A & B
B. B & C
C. A & C
D. A & D
Answer: D

19. For maximum acceleration of COM of a rolling sphere, applied force height h is
A. h = R
B. h = 2R
C. h = 0
D. Independent of h
Answer: D

20. Matching of physical quantities related to COM is correct for option
A. a
B. b
C. c
D. d
Answer: C

21. A merry-go-round completes 9 rotations in 18 s. Angular speed is
A. π/2 rad/s
B. π rad/s
C. 2π rad/s
D. 3π rad/s
Answer: B

22. A wheel reaches 10 rad/s in 5 s from rest. Angle turned is
A. 25 rad
B. 100 rad
C. 25π rad
D. 50π rad
Answer: A

23. A planet completes 2 revolutions in 360 days. Angular frequency is
Answer: C

24. Wheel with angular speed 88 rad/s makes revolutions per second
A. 7
B. 14
C. 28
D. 44
Answer: B

25. In rotational motion, linear velocities of particles are
A. Same
B. Different
C. Zero
D. Constant
Answer: B

26. A disc rotates at 10 rad/s. Max distance for block without slipping is
Answer: C

27. Angular velocity of minute hand (deg/s) is
A. 1.5
B. 1
C. 0.5
D. 0.1
Answer: D

28. Ratio of angular speeds for bodies in concentric circles is
A. 2:1
B. 1:2
C. 1:1
D. rB/rA
Answer: C

29. A body moving in a circle with constant speed has angular acceleration
A. v/r
B. Zero
C. vr
D. v/r²
Answer: B

30. In uniform circular motion, which quantity remains constant?
A. Velocity
B. Acceleration
C. Direction of motion
D. Kinetic energy
Answer: D

Conclusion

Practicing centre of mass and rotational motion MCQs helps aspirants bridge the gap between linear mechanics and rotational dynamics. These centre of mass and rotational motion mcqs questions reinforce the idea that while internal forces cannot alter centre-of-mass motion, mass distribution and geometry significantly influence rotational behavior. Understanding these centre of mass and rotational motion mcqs principles improves accuracy in solving problems involving rigid bodies, circular motion, and multi-particle systems.

Regular exposure to such centre of mass and rotational motion MCQs strengthens conceptual clarity, sharpens analytical thinking, and builds confidence for physics examinations.Understanding that internal forces cannot change the centre of mass motion, but can influence rotational dynamics, is crucial for solving such questions. These MCQs reinforce the idea that a body’s translation depends on net external force, whereas its rotation depends on net external torque, even when both occur simultaneously.