Work is defined as the scalar product of a force, F, and a
This is equivalent to the product of the force and the distance moved in the direction of the force. For instance, when a boundary of a system moves in the direction of the force acting on it, the surroundings do work on the system. If the direction of the movement is reversed, then the work is done by the system on its surroundings. The SI unit of work is joule (J) that is the same unit as energy.
Other units are: