Physics (AS & A Level) · Oct / Nov 2017 · Paper 11 · Question 11

Two solid spheres form an isolated system. Sphere X moves with speed 6 cm s–1 in a straight line directly towards a stationary sphere Y, as shown. The spheres have a perfectly elastic collision. After the collision, sphere X moves with speed 2 cm s–1 in the same direction as before the collision. What is the speed of sphere Y?

1. A2 cm s–1
2. B4 cm s–1
3. C6 cm s–1
4. D8 cm s–1

As printed in the paper