# A petrol-powered go-kart travels along a flat track at constant speed. Of the 50 000 J of chemical energy released by the fuel, 12 500 J is transferred as useful kinetic energy to the go-kart. Describe the useful energy transfer and the waste energy transfers that occur, and explain what is meant by the efficiency of this system.

> Pearson Edexcel International GCSE Physics (4PH1) — 4.1 Energy transfers · Describe · 4 marks

> A petrol-powered go-kart travels along a flat track at constant speed. Of the 50 000 J of chemical energy released by the fuel, 12 500 J is transferred as useful kinetic energy to the go-kart.

## Mark scheme (4 marks)

1. Chemical energy in the fuel is the input energy store / source
2. Useful energy transfer is to the kinetic energy store of the go-kart
3. Waste energy transfers include thermal/heat energy (due to friction / engine heating) and/or sound energy
4. Efficiency is the ratio of useful energy output to total energy input (× 100 %); here 12 500 / 50 000 = 25 %

## Key terms

- [chemical energy](https://www.gradenine.co.uk/glossary/chemical-energy)
- [kinetic energy](https://www.gradenine.co.uk/glossary/kinetic-energy)
- [useful energy transfer](https://www.gradenine.co.uk/glossary/useful-energy-transfer)
- [waste energy transfer](https://www.gradenine.co.uk/glossary/waste-energy-transfer)
- [efficiency](https://www.gradenine.co.uk/glossary/efficiency)

## Related

- [Revision notes for Pearson Edexcel International GCSE Physics (4PH1)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" 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-petrol-powered-go-kart-travels-along-a-79a3d391) · Published by Druglandscape Ltd.