Question

A ball kept in a closed container moves in it making collision with the walls. The container is kept on a smooth surface. The velocity of the centre of mass of :

• A. the ball remains fixed
• B. the ball relative to container remains fixed.
• C. the container remains fixed
• D. both container and ball remain fixed.

Answer 1

The correct option is D both container and ball remain fixed.

Since the container is closed, the collisions made by ball with the walls of container will not affect the mass of container and in turn there is no change in velocity of center of mass hence, both container and ball remain fixed.