Physics 9702 · AS & A Level · Linear momentum and its conservation
Linear momentum and its conservation — practice question
A wooden block slides along a horizontal frictionless surface, as shown in Fig. 2.1. The block has mass $85\,\text{g}$ and is travelling to the left at a velocity of $2.0\,\text{m s}^{-1}$. A steel ball of mass $4.0\,\text{g}$ is launched to the right. The steel ball, moving horizontally with a speed of $45\,\text{m s}^{-1}$, strikes the block and stays embedded in it. After the collision the block and steel ball both move with speed $v$.
(a)[2]
Calculate the value of $v$.
(b(i)-1)[1]
For the block and ball, state the relative speed of approach immediately before collision.
(b(i)-2)
For the block and ball, state the relative speed of separation immediately after collision.
(b(ii))[1]
Use your answers in (i) to state and explain whether this collision is elastic or inelastic.
(c)[2]
Use Newton’s third law to explain how the rate of change of momentum of the ball is related to the rate of change of momentum of the block during the collision.
(b(i).1)[1]
For the block and ball, state the relative speed of approach immediately before collision.
(b(i).2)[1]
For the block and ball, state the relative speed of separation immediately after collision.
Worked solution & mark scheme
This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: “application of momentum $p = mv$” …