Physics (AS & A Level) · Oct / Nov 2022 · Paper 13 · Question 10

Two blocks are at rest on a frictionless horizontal surface. One block is made of wood and the other block is made of steel. A steel ball is fired horizontally with a speed v at the wooden block. The ball embeds itself in the block, and the ball and block move together after impact. A second identical steel ball is fired horizontally with speed v at the steel block. The steel ball then rebounds back along its original path with speed v/2. [diagram: before impact and after impact for wood and steel blocks] The wooden block and the steel block have equal mass. Which statement about the blocks immediately after the collisions is correct?

1. ABoth blocks must travel with the same speed.
2. BThe steel block must travel faster than the wooden block.
3. CThe wooden block must travel faster than the steel block.
4. DThe masses of the blocks and the steel ball are needed to determine which block travels faster.

As printed in the paper