Convert energy units, joules, calories, btu, erg, kwh, mwh
Energy is a measure of how long we can sustain the output of power, or how much work we can do. There are two kinds of energy: potential and kinetic.
Potential energy is waiting to be converted into power. Gasoline in a fuel tank as an example. Kinetic energy is energy a body possesses because it is in motion.
Work is the application of a force over a distance. Work is equal to the product of the force and the distance through which it produces movement.