Mechanical work

In Newtonian mechanics, work is a measure of energy expended in applying force over a distance.

For the motion of a body against a constant force, work can be expressed as:

W = �

or, with the dot product expanded:

where

W : work (energy)
: force vector
: distance moved (also a vector)
α : angle between and

In modern physics, the term energy is generally used to refer to all forms of energy, including mechanical work.

The SI derived unit of work is the Joule, which in Newtonian mechanics is often referred to as a newton-metre (Nm). Other units include the erg, the foot-pound, and the foot-poundal.