Question

A ball hits a vertical wall horizontally at $10\,ms^{-1}$ and bounces back at $10\,ms^{-1}$ , then

• A. there is no acceleration because $ 10\,ms^{-1}-10\,ms^{-1}=0 $
• B. there may be an acceleration because its initial direction is horizontal
• C. there is an acceleration because there is a momentum change
• D. even though there is no change in momentum there is a change in direction. Hence it has an acceleration

Answer 1

Answer: (C)

As the ball bounces back with same speed so change in momentum $ =2mv $ and we know that force = rate of change of momentum ie, force will act on the ball so there is an acceleration.