# A hydraulic car lift uses a small piston to push oil through a pipe connected to a large piston beneath a car. Explain why the pressure exerted by the small piston is transmitted equally in all directions through the oil, and explain how this allows the large piston to exert a greater force on the car than the force applied to the small piston.

> Pearson Edexcel International GCSE Physics (4PH1) — 5.1 Density and pressure · Explain · 4 marks

> A hydraulic car lift consists of two pistons of different areas connected by oil-filled pipes. A mechanic applies a force to a small piston of area 0.002 m² to raise a car resting on a large piston of area 0.10 m².

## Mark scheme (4 marks)

1. Pressure in a fluid (liquid) acts equally in all directions / is transmitted equally throughout the oil
2. The same pressure acts on the large piston as on the small piston
3. Force = pressure × area, so a greater area produces a greater force (for the same pressure)
4. The large piston has a greater area than the small piston, so the upward force on the car is greater than the force applied by the mechanic

## Key terms

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

## 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-hydraulic-car-lift-uses-a-c7adcb10) · Published by Druglandscape Ltd.