Question

Choose the correct statement.
(A) The position of centre of mass of a system is dependent on the choice of co-ordinate system.
(B) Newton's second law of motion is applicable to the centre of mass of the system.
(C) When no external force acts on a body, the acceleration of centre of mass is zero.
(D) Internal forces can change the state of centre of mass.

• A. Both (A) and (B) are correct
• B. Both (B) and (C) are wrong
• C. Both (A) and (C) are wrong
• D. Both (A) and (D) are wrong

Answer 1

The correct option is D Both (A) and (D) are wrong

Acceleration of center of mass occurs due to external forces acting on the body only.

Thus $a_{cm}=\frac{F_{ext}}{m}$

Hence statements B and C are correct and statement D is wrong.

Also the position of center of mass is determined by the mass distribution in the body, hence being independent of coordinate system.

Hence correct answer is option D.