A force of 40 N is applied at right angles to a spanner, 0.25 m from the centre of a nut. Calculate the moment of the force about the nut. Give your answer to 2 significant figures.
[2 marks]
Total for this question: 2
All equation deep-dives
Moments
Forces
AQA 8463
On the equation sheet
ORIGINAL
M = F d
d is the PERPENDICULAR distance from the pivot to the line of the force, and balance means clockwise = anticlockwise.
Current GCSE 8463 policy: The full AQA GCSE Physics 8463 equation sheet is provided with both papers in 2026; use fluency practice to learn selection and rearrangement, not to memorise the list.
Board and spec code confirmed against AQA 8463 · registry checked 2026-07-17How this checking works
Know the equation
| Symbol | Quantity | Unit |
|---|---|---|
| M | moment of a force | N m |
| F | force | N |
| d | perpendicular distance from the pivot to the line of action of the force | m |
Rearrangements
- F = M / d
- d = M / F
Apply it — mark your own working
Work each one out on paper first, then reveal the mark scheme and tick the marks you actually earned. That is exactly how you should mark past papers.
Q1
Do the calculation on paper first — then mark it.
Q2
A seesaw is pivoted at its centre. A child of weight 300 N sits 1.6 m from the pivot. A second child of weight 400 N sits on the other side so that the seesaw balances. Ignore the weight of the seesaw. Calculate the distance of the second child from the pivot. Give your answer to 2 significant figures.
[3 marks]
Total for this question: 3
Do the calculation on paper first — then mark it.
Where the marks get lost
- Measuring d to the wrong point: it is the perpendicular distance from the PIVOT to the line of the force.
- Leaving distances in cm: 25 cm = 0.25 m, or the moment comes out 100 times too big.
- For a balanced object, setting the two forces equal instead of the two moments (clockwise moment = anticlockwise moment).
Exam tip: For a balance question, write 'total clockwise moment = total anticlockwise moment' as your first line, then put one F x d on each side.
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