Skateboard Ball Throwing Game · CAP 2022 #3

Physics · mechanics

Problem

Ann and Betty are good at throwing and catching balls. They can always throw a ball for the other to catch it with only negligible motion. This time they want to have more fun and play the game on skateboards as shown. Initially they are both at rest. Ann first throws the ball to Betty at speed u. After catching the ball, Betty throws the ball back to Ann at the same speed. After Ann catches the ball, Betty is moving faster than Ann by how much? Assuming mass of the ball = m mass of Ann and the skateboard = mass of Betty and the skateboard = M a) Mm+2m2M(M+m)u\frac{Mm+2m^2}{M(M+m)}u b) 2m2M(M+m)u\frac{2m^2}{M(M+m)}u c) 2mM+mu\frac{2m}{M+m}u d) −2mM+mu-\frac{2m}{M+m}u e) muM\frac{mu}{M}

Browse the problem library