In the ideal case of a perfectly elastic collision between two bodies no damage is done to the bodies since they do not absorb any energy, except temporarily and reversibly. Damage to a body requires irreversible expenditure of energy, so the collisions which cause the damage must be inelastic. The extent to which a collision is inelastic depends on the materials and forces involved. Exceeding the elastic limit of the material produces permanent deformation and exceeding the breaking strain results in rupture.