This is just a concept question. Say you have a spring arranged vertically with an object on the end of it. The spring is compressed.. At some point you, the system is released from compression. When calculating the velocity at which the object loses contact, I understand that you use the conservation of energy. Eo =Ef ---> But do you have a final PE? Or is it all kinetic energy? Since it is returning to equilibrium position (where the compression x is zero), I would think that there is no mgh, but then again it has gained displacement in the vertical direction. 0.5KX2 = 0.5mv2 OR 0.5KX2 = 0.5mv2 + mgh?