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Physics · SYSTEMS OF PARTICLES AND ROTATIONAL MOTION
हिन्दीGiven below are statements regarding the motion of the centre of mass of a system: (A) Motion of the centre of mass depends only on external forces. (B) The centre of mass of a system must always lie inside the material boundary of the body. (C) Internal forces cancel out in pairs and do not contribute to the acceleration of the centre of mass. (D) If the net external force on a system is zero, the centre of mass must be at rest. Choose the correct answer from the options given below:
Correct answer · Option 3
(A) and (C) only
Explanation
(A) and (C) are correct. (B) is false (e.g. ring), and (D) is false because if \( \mathbf{F}_{\text{ext}} = 0 \), the centre of mass moves with constant velocity (not necessarily at rest).
