# Power calculations (P = E/t)

I can describe power and calculate the rate at which energy is transferred by a force.

# Power calculations (P = E/t)

I can describe power and calculate the rate at which energy is transferred by a force.

## Lesson details

### Key learning points

- Power is equal to the rate at which work is done.
- Power is equal to the rate at which energy is transferred.
- Power = work done ÷ time.
- Power is measured in watts (W).

### Common misconception

Pupils often mix up the terms power and force, which are often used interchangeably in everyday speech.

Provide opportunities for pupils to describe events in which the terms need to be used appropriately, for example in lifting two different sized weights (different forces) whilst increasing their energy at the same rate (same power).

### Keywords

Work - Work is done whenever a force makes an object move. The amount of work is force multiplied by distance moved in the direction of the force.

Power - Power is the rate at which work is done.

Rate - The rate at which something changes is usually equal to the amount of change each second.

Watt (W) - The unit for measuring power is the watt (W).

Kilowatt (kW) - A thousand watts is called a kilowatt (kW).

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Video

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## Starter quiz

### 6 Questions

## Exit quiz

### 6 Questions

newtons (N)

watts (W)

metres per second (m/s)

joule (s)