FORCES AND SHAPE
2 marks · NormalExplain why friction is sometimes useful and sometimes a problem in everyday life. Refer to one example of each.
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Must show: One use of friction (e.g. tyre grip or brakes), One problem caused by friction (e.g. heat in machinery, slows moving parts)
Common mistakes: Giving two examples of only one situation
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Marking points
B1 · 1 mark · Gives a valid example where friction is useful
B2 · 1 mark · Gives a valid example where friction is a problem
Worked solution
Friction is useful, for example, between car tyres and the road to prevent slipping. However, friction in the moving parts of a machine can cause unwanted heating and wear.