# A building lift (elevator) carries passengers upwards at a steady speed. Explain why a lift motor with a greater power output is needed to move the same passengers through the same height in a shorter time.

> Pearson Edexcel International GCSE Physics (4PH1) — 4.2 Work and power · Explain · 4 marks

> Two identical lifts in a hotel carry passengers of the same total weight through the same vertical height. Lift A completes the journey in 20 s, whilst Lift B completes the identical journey in 10 s.

## Mark scheme (4 marks)

1. Both lifts do the same amount of work / transfer the same amount of energy (because force and distance are identical)
2. Power is the rate at which work is done / energy is transferred
3. A shorter time (with the same work done) means a greater power is required
4. Correct qualitative link: Lift B (10 s) requires twice the power of Lift A (20 s) because the same work is done in half the time

## Key terms

- [power](https://www.gradenine.co.uk/glossary/power)

## Related

- [Revision notes for Pearson Edexcel International GCSE Physics (4PH1)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-building-lift-elevator-carries-passengers-859c6a66) · Published by Druglandscape Ltd.