Problem 4: Suppose a clay model of a kangaroo has a mass of 0.18 kg and glides on ice at a speed of 0.85 m/s. It crashes into another clay model, which is initially motionless and has a mass of 0.36 kg. Both being soft clay, they naturally stick together. What is their nal velocity in meters per second? Problem 6 : A 81.5-kg ice hockey player hits a 0.125-kg puck, giving the puck a speed of 35 m/s. If both are initially at rest and if the ice is frictionless, how far, in centimeters, does the player recoil in the time it takes the puck to reach the goal, 12.5 m away