Answers to AQA GCSE Balancing Moments

Practice questions

1.State the principle of moments

When an object is balanced, the total clockwise moment about a point is equal to the total anticlockwise moment

2. Use the image below to answer the following questions.

Calculate the length of the distance between the counterweight on the left hand side and the pivot. This unknown distance has been marked on the diagram as ?m.

F₁ = 10000N, d₁ = ?m, F₂ = 12000N and d₂ = 3m

F₁ x d₁ = F₂ x d<sub>2

d1</sub> = (F₂ x d₂)/F<sub>1

d1</sub> = (12000Nx3m)/10000N

_d1 = 3.6m

3. Use the image below to help you to answer the following question

The man has a clockwise moment of 190Nm. Both of his feet are equal distance from the pivot. Calculate the distance between the pivot and his left foot. This distance has been labelled as ?m in the diagram above.

F₁ x d₁ = F₂ x d₂

Clockwise moment = Force x distance

Distance = Clockwise moment/Force

Distance= 190Nm/250m = 0.76m

As the feet are equal distance from the pivot the other foot is 0.76m from the pivot as well, so the distance is 0.76m