A man stands on a frictionless horizontal ground. He slides a 10 kg block on the surface with a speed of 3 m/s relative the ground, towards a vertical massive wall. The wall itself it moving towards the man at a constant speed of 2 m/s. The block makes a perfectly head on elastic collision with the wall, rebounds and reaches back to the man 3 second after the throw. At the moment the block was thrown, the wall was at a distance of 10 m from the man.
(a) Find the mass of the man.
(b) Find the ratio of work done by the man in throwing the block to the work done by the wall on the block.
