Say a mass is suspended vertically from a spring and is in equilibrium. What is its potential energy? I think its zero because while it has gravitational potential that would allow it to do work downwards, it also has potential energy from the spring upwards. So do these cancel out? It seems like they have to for SHM equations to work out. What is its potnetial energy when it is pulled down m meters? (1/2)km^2 This isn't homework just a a concept I'm confused on.