4) A man of mass 101 kg is standing on a cart of mass 351 kg. He jumps off the cart at a speed of 4.5 m/s relative to the cart. How fast does the cart move?

5) Baby bear of mass 20 kg and Mother bear of mass 40 kg are at rest 10 m apart. Father bear of mass 80 kg slides along the path at 15 m/s. He collides with Mother bear and she bounces ahead to collide with Baby bear. If all collisions are perfectly elastic and one dimensional and there is no friction on the straight and level path, calculate the speed of Baby bear.