When a force causes a body to move, work is being done on the object by the force. Work is the measure of energy transfer when a force 'F' moves an object through a distance 'd'.
So when work is done, energy has been transferred from one energy store to another, and so:
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, so:
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?
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?
A current will flow in a circuit when there is a potential difference applied to the circuit. The power supply (or cell or battery) gives an amount of energy to each coulomb of charge flowing.
A 6 volt cell, for example, gives 6 joules of energy to each coulomb. We can also use the word 'work' instead of the word 'energy' because:
work done = energy transferred
which can be rearranged to
energy = voltage × charge
can be called energy transferred or work done by the power supply.
How much energy is transferred (or work done) when 3 C of charge moves through a potential difference of 6 V across a resistor?
If the 3 C of charge flows in 6 seconds, how big is the current in the resistor?
What is the total energy dissipated in the resistor?
Note that the first answer and the last answer agree.