Question

 Johnny Quest is a boy of mass 70 kg. He is standing on a diving board bent 50 cm down and of stiffness 20 kN/m and he is 5 m high above the tranquil waters of the blue lagoon.  He is flung into the air by the diving board towards the top of a coconut tree.  If he lands at a speed of 3 m/s then find the height of the tree.  Assume he does not lose any energy as heat due to drag – the drag is negligible and the efficiency is 100%.