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GCSE Physics forces and motion questions

Calculate average speed and acceleration, then use F = ma.

Practise

Rearrange for mass

An object with constant mass accelerates at 2.3 m s⁻² under a resultant force of 4.1 N. Find its mass in kg. Give your answer to 3 significant figures.

Equation: F = ma

Treat the given values as exact unless an uncertainty is stated.

Use decimals or e notation, e.g. 4.2e-3. Enter the unit separately.

Hint

Rearrange F = ma to m = F / a.

Worked solution
  1. m = F / a = 4.1 / 2.3 kg.
  2. Answer: 1.78 kg (3 significant figures).
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Question type: Mixed practice
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Foundation and Higher: this set covers content common to both tiers. Some calculations need several steps.

Speed, acceleration and force

Average speed uses the total distance travelled and elapsed time. For acceleration, subtract the initial velocity from the final velocity, keeping the stated positive direction. F = ma uses the resultant force. Force diagrams, two-dimensional resolution and momentum are outside this set.

GCSE scope

AQA 8463: 4.5.1.4; 4.5.6.1.2, 4.5.6.1.5, 4.5.6.2.2; OCR Gateway J249: P2.1; P2.2; PM2.1i–ii, PM2.2i. Tasks cover the selected skills listed above.

AQA specification · OCR Gateway specification

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