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Levers and moments – practice for Years 7–8

Sample questions on Levers and moments with the right answer and a worked solution, from easy to hard. In the Pickles Academy app a child gets new questions of the same kind every time, so they can't just learn the answers by heart.

Subject
Physics
Year
Years 7–8
Curriculum area
Motion and forces

Question types: Balancing a lever

Rule: Levers and moments

A lever balances when force × distance is the same on both sides: F₁ × d₁ = F₂ × d₂.

The distance is measured from the pivot. On the shorter side you need a bigger force.

Example: 30 N at distance 3 and distance 5 on the right: 30 × 3 = F × 5, so F = 90 ÷ 5 = 18 N

Watch out: Measure the distance from the pivot, not from the end of the lever.

Sample questions

  1. Question 1 Easy

    The lever is balanced. How large is the weight on the right?

    11223344556660 N?
    Show the solution
    Answer: 30 N

    How it works: F₁ × a₁ = F₂ × a₂: 60 N × 30 cm = F₂ × 60 cm; F₂ = 1800 ÷ 60 = 30 N.

  2. Question 2 Normal

    The lever is balanced. How large is the weight on the right?

    11223344556610 N30 N?
    Show the solution
    Answer: 70 N

    How it works: 10 N × 50 cm + 30 N × 30 cm = F × 20 cm; F = 1400 ÷ 20 = 70 N.

  3. Question 3 Hard

    The marks on the lever are 10 cm apart. How far from the pivot must the 60 N weight hang for the lever to balance? Give the distance in cm.

    11223344556660 N60 N?
    Show the solution
    Answer: 40 cm

    How it works: 60 N × 40 cm = 60 N × a; a = 2400 ÷ 60 = 40 cm.

Related topics

All Physics topics

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