I have a vertical spring of spring constant k with a pan on the top. I place a box of mass M on it and let it move to the equilibrium position a distance d below the unstretched position of the spring. I then push it down until the position of the pan is 3d below the equilibrium position and release it from rest. The spring will accelerate the box
upward and the box will rise up off the pan. If all the energy stored in the spring was transferred to the box how high will it rise above the unstretched position?