Key Stage 3
Meaning
A moment is the turning effect of a force.
About Moments
- When a force acts on an object with a pivot it becomes a turning force called a moment.
- A moment can be calculated by multiplying a force by the distance from a pivot.
- The units of a moment are Newton Metres (Nm).
- Moments can be used to make Force Multipliers using a pivot and lever.
- The longer the lever, the larger the moment that can be produced.
Using moments an effort can be used to lift a load. If the pivot is closer to the load than the effort then the force of effort can be smaller than the load to lift the object. |
Equation
Moment = Force x Perpendicular distance from the pivot.
\[M = F \times d\] Where:
- M = Moment
- F = Force
- d = Perpendicular distance from the pivot.
Example Calculations
A 20N force of effort is applied at a perpendicular distance of 0.15m from the pivot. Calculate the Moment. | A 20N force of effort is applied at a perpendicular distance of 14cm from the pivot. Calculate the Moment. | A 20N force of effort is applied at a perpendicular distance of 100mm from the pivot. Calculate the Moment. |
Force = 20N Perpendicular distance = 0.15m \(M = F \times d\) \(M = 20 \times 0.15\) \(M = 3.0Nm\) |
Force = 20N Perpendicular distance = 14cm = 0.14m \(M = F \times d\) \(M = 20 \times 0.14\) \(M = 2.8Nm\) |
Force = 20N Perpendicular distance = 100mm = 0.10m \(M = F \times d\) \(M = 20 \times 0.10\) \(M = 2.0Nm\) |
A 30N force of effort is applied at a perpendicular distance of 0.18m from the pivot. Calculate the Moment. | A 30N force of effort is applied at a perpendicular distance of 19cm from the pivot. Calculate the Moment. | A 30N force of effort is applied at a perpendicular distance of 200mm from the pivot. Calculate the Moment. |
Force = 30N Perpendicular distance = 0.18m \(M = F \times d\) \(M = 30 \times 0.18\) \(M = 5.4Nm\) |
Force = 30N Perpendicular distance = 19cm = 0.19m \(M = F \times d\) \(M = 30 \times 0.19\) \(M = 5.7Nm\) |
Force = 30N Perpendicular distance = 200mm = 0.20m \(M = F \times d\) \(M = 30 \times 0.20\) \(M = 6.0Nm\) |