Final answer:
The subject of this question is Physics. According to the Law of Conservation of Energy, mechanical energy remains constant in a closed system with no external dissipative forces acting.
Step-by-step explanation:
The subject of this question is Physics.
In Physics, the concept of energy conservation is widely studied. According to the Law of Conservation of Energy, energy can be transformed from one form to another, but the total energy of an isolated system remains the same. This means that the total mechanical energy, which is the sum of kinetic and potential energy, does not change in a closed system with no external dissipative forces acting. Therefore, the total amount of mechanical energy remains constant even if it changes its form.