Physics 9702 · AS & A Level · Momentum and Newton's laws of motion
Momentum and Newton's laws of motion — practice question
A small ball is released from rest at a height of $h_1$ above the ground and travels straight down. It strikes the ground and rebounds straight up, rising to a greatest height of $h_2$. Fig. 4.1 illustrates the ball immediately before and immediately after it contacts the ground. The ball has mass $0.25\ \text{kg}$ and remains in contact with the ground for $0.18\ \text{s}$. Immediately before impact, the ball’s speed is $5.2\ \text{m s}^{-1}$. Immediately after it leaves the ground, its speed is $3.6\ \text{m s}^{-1}$. The effect of air resistance on the ball is negligible.
(a)[1]
State and explain if the collision is elastic or inelastic.
(b(i))[2]
Calculate the change in momentum of the ball during the collision with the ground.
(b(ii))[2]
Determine the average force on the ball during the collision with the ground.
(c)[3]
Calculate the ratio $\frac{h_2}{h_1}$.
Worked solution & mark scheme
This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: “The total kinetic energy changes/decreases so the collision is inelastic.” …