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Work

Work is the energy a force transfers while it acts as something moves. Only the component of the force along the motion does work: a force perpendicular to the motion does zero work, and a force acting against the motion, like friction, does negative work.

W=Fscos⁡θW = Fs\cos\thetawork done by a force

Symbols

WWworkJ
FFforceN
ssdisplacementm
θ\thetaangle between force and motion°

Example

You pull a sled with F=60F = 60 N in a rope at 30∘30^\circ to the ground, over 1515 m. The work is W=60⋅15⋅cos⁡30∘≈779W = 60\cdot 15\cdot\cos 30^\circ \approx 779 J.

If you carry something horizontally at constant height, the upward force does zero work – it is perpendicular to the motion.
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Part of Foundations of Physics: Work, energy and power.