Work done and energy transfer from work

A force does work on an object when it causes the object to move. The work done by a force is given by \(\text{work}=\text{force}\times\text{distance moved (in the direction of the force)}\).
This can be written as \(W=Fs\) where \(W\) is the work done in J, \(F\) is the magnitude of the force doing the work in N, and \(s\) is the distance the force causes an object to move in m. This equation assumes the object is moving in the direction of the force. No work is done if the object is stationary or the force is perpendicular to the direction the object is moving in.
Work is measured in joules, J. One joule is the work done by a 1 N force to move an object 1 m. The units joules and Newton-metres, Nm, are the same.
An energy transfer will occur when a force does work. This is why work and energy have the same unit. For instance, lifting an object will cause work to be transferred to gravitational potential energy. Holding a heavy object stationary will cause you to get tired as your muscles transfer energy, but they do no work.
Pushing or pulling an object will cause work to be transferred to kinetic energy.
If you are doing work against friction, then this work will be transferred to thermal energy in the object. This is why objects heat up when we rub them together.

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