1. The problem statement, all variables and given/known data A harmonic oscillator with a vertical mass on a string has a hanging mass of 2m and a spring constant of K. It oscillates with an amplitude of Z. When its position is at a distance Z/2 of the equilibrium point, its potential energy is Ui. What is the maximum kinetic energy Km? 2. Relevant equations E=1/2mV2 + 1/2mA2 3. The attempt at a solution I realized that the max kinetic energy must be equal to the to the max potential energy because total energy is constant. I just don't know where to put the equations to make it fit. Can someone show me the set up? The answer give was Km = 4Ui Thanks in advance!