I'm doing a nuclear chemistry project right now, and I am able to solve all of the problems involving binding energy and mass defect, however I have one conceptual question. Why is it that when the nucleons combine with each other they let off energy? At first I thought it was their kinetic energy being let off because they're being held in place by the strong nuclear force, but that seems wrong for some reason. My book doesn't go into any detail about this, can someone try explaining it? Thanks in advance.