You are standing on a sheet of ice that covers the football stadium parking lot in Buffalo; there is negligible friction between your feet and the ice. A friend throws you a ball of mass 0.400 kg that is traveling horizontally at 12.0 m/s. Your mass is 65.0 kg.
a. If you catch the ball, with what speed do you and the ball move afterwards?
b. If the ball hits you and bounces off your chest, so afterwards it is moving horizontally at 9.00 m/s in the opposite direction, what is your speed after the collision?