A mass is suspended vertically from a spring. It is lifted to point P and then let go. The mass then moves back and forth between point P and a lower point Q. During these oscillations, which forms of energy repeatedly rise and fall?
- Agravitational potential energy, kinetic energy and elastic energy
- Bgravitational potential energy and kinetic energy only
- Cgravitational potential energy, kinetic energy and internal energy
- Dinternal energy and elastic energy