Question Constellation Sign up for free AQA · GCSE · Combined Science · Higher
Energy changes during braking
When the brakes are used, the temperature of the brakes increases. Explain why. Use ideas about energy in your explanation.
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Marking points
- 1 State that the car's kinetic energy decreases when the brakes are used.
- 2 Link this to an increase in the internal or thermal energy store of the brakes.
Full-mark answer
When the brakes are used, the car loses kinetic energy. This energy is transferred to the brakes, increasing their internal or thermal energy store, so their temperature rises.
Why this answer loses marks
The brakes get hot because of friction.
Friction is relevant, but the question asks for ideas about energy; the response needs kinetic energy decreasing and internal or thermal energy increasing.