Question

A lead ball strikes a wall and falls down while a tennis ball having the same mass and velocity strikes the wall and bounces back. Check the correct statement.

• A. The momentum of the lead ball is greater than that of the tennis ball.
• B. The lead ball suffers a greater change in momentum compared with the tennis ball.
• C. The tennis ball suffers a greater change in momentum as compared with the lead ball.
• D. Both suffer an equal change in momentum.

Answer 1

The correct option is C The tennis ball suffers a greater change in momentum as compared with the lead ball.

Change in the momentum
= Final momentum - initial momentum

For lead ball, $\Delta {\overrightarrow{p}}_{lead}=0-m\overrightarrow{v}=-m\overrightarrow{v}$
For tennis ball, $\Delta {\overrightarrow{p}}_{tennis}=-m\overrightarrow{v}-m\overrightarrow{v}=-2m\overrightarrow{v}$
i.e. tennis ball, suffers a greater change in momentum.