MYP Physics Work and Power, Efficiency Notes

How Does Work Link Forces To Energy Transfer

1. In physics, work is not the same as effort or tiredness.
2. Work describes how energy is transferred when a force causes an object to move.
3. Work is only done when a force causes movement in the direction of that force.
4. If there is no movement, no work is done, even if a force is applied.

Calculating Work Done

1. The amount of work done depends on how large the force is.
2. It also depends on how far the object moves.
3. The distance considered is only the distance moved in the direction of the force.

$$W = Fd$$

where:

1. $W$ is work (joules, J)
2. $F$ is force (newtons, N)
3. $d$ is distance moved (metres, m)

When Work Is Done

1. Work is done when a force causes movement in the same direction as the force.
2. Work is also done when movement is opposite to the force, such as lifting against gravity.
3. In these cases, energy is transferred into or out of the object.

When Work Is NOT Done

1. No work is done if an object does not move.
2. No work is done if the motion is at right angles to the force.
3. Even strong forces may transfer no energy if they do not cause movement.