SUPERBALL REBOUND
Craig has a superball – so super that when you drop it, it bounces right back to the height you dropped it from. He’s wondering about what would happen if he threw the ball at something moving. Suppose he was standing on a railway line and a diesel train was bearing down on him at 50 mph (don’t try this at home!). Suppose he then threw the superball at 20 mph straight at the oncoming train. When the ball bounced off the front of the train, how fast would the ball be coming towards Craig?