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 = F d (dot product)

where
  • W : work (energy)
  • F : force
  • d : distance moved

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. Other units include the erg, the foot-pound, and the foot-poundal.