the 150kg mass of the pile driver is dropped 4m vertically and lands, without bouncing, on the end of the pile of mass 250 kg and drives it 0,1m before coming to rest. assume that the retarding force of the pile to motion is constant. find: a) the potential energy of the mass at the top of the lift by reference to the top of the pile. b) by applying the concept of conservation of energy the velocity of the mass just before impact with a pile. c) the velocity of the mass and the pile directly after the impact d) the deceleration of the pile e) the retarding force experienced by the pile f) the work done driving the pile in each driving cycle.