A 0.105-kg hockey puck moving at 26 m/s is caught and held by a 72-kg goalie at rest. With what speed does the goalie slide on the ice?

Answer 1

Mpuck*Vpuck = (Mpuck+Mgoalie)*Vfinal

Vfinal = (0.105/72.1)*26 m/s

It's called momentum conservation

It assumes that goalie is not in contact with the goal