When a force causes a body to move, work is being done on the object by the force. Work is the measure of how much energy is transferred when a force ( ) moves an object through a distance ( ).
So when work is done, energy has been transferred from one energy store to another. Therefore:
energy transferred = work done
Energy transferred and work done are both measured in joules (J).
The amount of work done when a force acts on a body depends on two things:
The equation used to calculate the work done is:
work done = force × distance
This is when:
In this example, a force of 10 N causes the box to move a horizontal distance of 2 m.
= 10 × 2
= 20 J
A horizontal force of 50 N causes a trolley to move a horizontal distance of 30 m. How much work is done on the trolley by the force?
= 50 × 30
= 1,500 J
12,000 J of energy is supplied to move a small truck a distance of 80 m. What is the size of the force applied?
= 150 N