Is it true that energy cannot be created or destroyed?

Answer by  willard (874)

It is absolutely true that energy cannot be created or destroyed, only converted from one form to another. This Law, known as the Law of Conservation of Energy, is one of the most cherished principles of physics. Energy conservation follows from the invariance physical laws with respect to variations in time.

Answer by  tracker76 (135)

Yes. This is known as the Law of Conservation of Energy, and is an empirical law of physics. In a closed system, or an isolated system, the amount of energy always remains constant. However, the form of the energy can change - ie kinetic energy can be converted to thermal energy. See http://en. wikipedia. org/wiki/Conservation_of_energy.