# An electric motor is used to lift boxes in a warehouse. Explain why the electric motor is not 100% efficient, and describe one way in which the efficiency of the motor could be improved.

> WJEC GCSE Physics (Wales) — 1.6 Distance, speed and acceleration · Explain · 4 marks

> Electric motors are used in warehouses to lift heavy boxes from floor level to storage shelves. During operation, the motor becomes warm to the touch.

## Mark scheme (4 marks)

1. The motor produces waste energy transfer (to the surroundings)
2. The waste energy transfer is in the form of heat/thermal energy (and/or sound)
3. The useful energy transfer is only the gravitational potential energy gained by the boxes
4. Efficiency can be improved by lubrication (of moving parts) to reduce friction

## Key terms

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

## Related

- [Revision notes for WJEC GCSE Physics (Wales)](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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