Physics (AS & A Level) · May / June 2018 · Paper 12 · Question 9

An elastic collision occurs between two bodies X and Y. The mass of body X is m and the mass of body Y is 4m. Body X travels at speed v before the collision and speed 3v/5 in the opposite direction after the collision. Body Y is stationary before the collision. [diagram: before — X (m) moving right with speed v, Y (4m) stationary; after — X (m) moving left with speed 3v/5, Y (4m) moving right] What is the kinetic energy of body Y after the collision?

1. A8/10 mv²
2. B34/50 mv²
3. C16/50 mv²
4. D1/5 mv²

As printed in the paper