Which of the following statements is/are true?
Check all that apply.
(A) The total mechanical energy of a system, at any one instant, is either all kinetic or all potential energy.
(B) The total mechanical energy of a system is equally divided between kinetic and potential energy.
(C) Mechanical energy can be dissipated to nonmechanical forms of energy.
(D) The total mechanical energy of a system is constant only if conservative forces act.
(E) The total mechanical energy of a system is constant only if nonconservative forces act.