Question

Two particles of mass 1 kg and 3 kg move towards each other under mutual force of attraction. No other force acts on them. When the relative velocity of approach of the two particles is $2m{s}^{-1}$ their centre of mass has a velocity of $0.5m{s}^{-1}$ and when their velocity of approach become $3m{s}^{-1}$, the velocity of their centre of mass is $0.75m{s}^{-1}$. Then,

• A. Above statement is correct
• B. Above statement is false
• C. Above statement may be correct or incorrect
• D. Velocity of centre of mass can change in the given case

Answer 1

Answer: (B)

Above statement is false

The status of the center of mass cannot be changed by the internal forces. As there is no external force the center of mass will continue to travel with the same velocity of 0.5 m/s, although, the velocity of different particles of the system may change due to the action of internal forces.