Law of Conservation of Mechanical Energy - General version

Description

Energy can be neither created nor destroyed.
Total energy is constant in any process. It may change in form or be transferred from one system to another, but the total remains the same.
If a system has a definite temperature, then its total energy has three distinguishable components. If the system is in motion as a whole, it has kinetic energy. If the system as a whole is in an externally imposed force field (e.g. gravity), it has potential energy relative to some reference point. Finally, it has internal energy, which is a fundamental quantity for thermodynamics.