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.