What is work?

Work is done when a force moves.

Everyday examples of work include walking up a flight of stairs, lifting heavy objects, pulling a sledge and pushing a shopping trolley.

Work is not done when holding a bag stationary or a book at arm’s length because although a force is being applied, the force does not move.

A man pushes a box with a force of 10 newtons to move it a distance of 2 metresA man pushes a box with a force of 10 newtons to move it a distance of 2 metres

Calculating work done

Illustration shows triangle divided into three segments: W is in the upper segment, F in the bottom left and d in the bottom right.

Here is the equation that relates to work done, force applied, and distance moved in the direction of the force.

\text{Work done} = {\text{Force}}\times{\text{distance}}

\text{W} = {\text{F}}\times{\text{d}}

where

W is work done measured in joules, J

F is force measured in newtons, N

d is distance measured in metres, m

In the example above, 10 N is applied to move the box 2 m.

Work done W = Fd

F = 10 N

d = 2 m

Work done = 10 × 2 = 20 J

The work done pushing the box 2 m is 20 J.

Equations for calculating work

W=FdW=Fxd
F= \frac{\text{W}}{\text{d}}F = W ÷ d
d= \frac{\text{W}}{\text{F}}d = W ÷ F