Number 8
3 marks · NormalExplain why a bicycle tyre in contact with the ground at a smaller area produces a greater pressure, even if the weight of the bicycle and rider remains the same. Use the pressure formula in your explanation.
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Pressure increases as the contact area decreases (for the same force), since pressure = force / area.
Must show: States or uses pressure = force/area, Discusses effect of decreasing area on pressure, Relates this to same force (weight)
Common mistakes: Confusing area and force
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Marking points
B1 · 1 mark · Writes or refers to the formula: pressure = force / area.
M1 · 1 mark · Explains that for the same force, decreasing area increases pressure.
A1 · 1 mark · Correctly states that smaller area will result in greater pressure, backed by reasoning.
Worked solution
Pressure is calculated using the formula:
If the weight (force) is the same but the area of contact is smaller, the denominator decreases, which means the pressure increases.
So, a bicycle tyre with a smaller contact area produces a greater pressure on the ground.