Answers to AQA GCSE Balancing Moments made more complex(Physics)

Calculations using Principle of Moments

Force 1, F1 x distance 1, d= Force 2, F2 x distance 2, d2

Practice questions

1.Use the image below to answer the following questions

sack barrow moments question

The weight of the box on the trolley is 500N. The line of action for the weight force is 0.25m from the pivot. A vertical force is applied to the handle that is 1.3m from the line of action of vertical force to the line of action of the weight force for the box to hold the trolley stationary.

Calculate the size of the  force F2.

Force 1, F1 x distance 1, d= Force 2, F2 x distance 2, d2

d2 = 1.3m, F1 = 500N, d1 = 0.25m

F2  = (F1 x d1)/d2

F2 = (500N x 0.25m)/1.3

F2 = 96.1N

To help you understand better the anticlockwise and clockwise moments have been drawn onto the diagram below:

 

clockwise and anticlockwise moments drawn onto sackbarrow question

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

Moments question using a forklift truck

Calculate the size of the counter balance force.

Force 1, F1 x distance 1, d= Force 2, F2 x distance 2, d2

F1 = 3000N, d1 = 1m, F2 = ?N and d2 = 1.5m

F2   = (F1 x  d1) x  d2

F2 = (3000N x 1m)/1.5m

F2 = 2000N


To help you understand better the anticlockwise and clockwise moments have been drawn onto the diagram below:

Clockwise and anticlockwise moments on forklift truck

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

Man doing wheelie, moment question

The position of the pivot is on the back wheel.  There is a distance of 0.2m from pivot to the line of action for the force of 500N. There is a distance of 1.3m from the pivot to the line of action for F1.

Calculate the size  of F1.

Force 1, F1 x distance 1, d= Force 2, F2 x distance 2, d2

F2 = 500N, d2 = 0.2m, F1 = ?N and d1 = 1.3m

F1   = (F2 x  d2)/d1

F1 = (500N x 0.2m)/1.3m

F1 = 76.9

To help you understand better the anticlockwise and clockwise moments have been drawn onto the diagram below: