Question

It is a easier to the stop a tennis ball as compared to a cricket ball when both are travelling with the same velocity

Answer 1

It is because a tennis ball is lighter than a cricket ball.

Momentum = Mass × Velocity
And momentum produced by a tennis ball is smaller than that of a cricket.

So we need to produce a larger retarding force in order to stop a cricket ball than that of in tennis ball.

Answer 2

If both are in same velocity..it depends upon the Element or materials the balls are made of..tennis ball is hollow and can be called as spongy so it Just Absorbs the energy derived form its velocity whereas a cricket ball is hard and thus is more difficult to Catch or stop..