Work Done

Work done is a way of transferring energy from one place to another. The amount of work done is the amount of energy required to do something. This something could be moving an object from point A to point B or by lighting a light bulb light up in a circuit.

Ways of Work

The three different types of work we are interested in are:

Work done via forces
Work done via electricity
Work done via heating

These are ways of transferring energy from a source to an object.

Equation

Mechanical work done (work done via forces) can be described and recalled by the following:

Work Done = Force x distance

W = F x d

W = Work Done (Joules, J or newton-metres, Nm)
F = Force (Newtons, N)
d = distance (metres, m)

Wasted Energy

Not all energy is transferred when doing work. Some of it is ‘wasted’. This means that it is transferred into a different energy store that is not useful for the object.

For example, the useful energy in a car is__ kinetic__ but some of the energy is wasted as__ thermal energy__.

In all cases, wasted energy is dissipated (spreads out) into the surroundings. This causes the surroundings to heat up and the temperature increases.

How much work was done in moving an object 2.5m with a force of 14N?: Your answer should include: 35J / 35Nm
How many Joules is 150Nm?: 150J
If a person had to do 12J of work on an object, how far has it moved if it was pushed with a force of 10N?: 1.2m