Moment formula
We can calculate the moment (M) using the formula:
Where:
M is the moment- %F$ is the force
d is the perpendicular distance from the centre
Units
We can calculate a moment using
- Force is measured in newtons
- Perpendicular distance is measured in metres
So if we do
Example calculations
A force of 5N is applied 10m away from a pivot. Calculate the moment.
F=5 d=10 M=Fd - $M=(5)(10)%
M=50\space Nm
A force of 5N is applied 2m away from the pivot. Another force, F, is applied 5m away from the pivot. The overall moment is 25Nm . Calculate F.
- Total moment = sum of all moments
M_1=5\times2=10 M_2=M_{total}-M_1 M_2=25-10 M_2=15 M_2=F\times5=15 F=3N
A person is capable of exerting a force of 200N onto a plank of wood. If the moment needed to snap the wood is 1200Nm , how far away does the person need to press down on the plank of wood?
M=Fd d=\frac MF d=\frac{1200}{200} d=6m
flashcards
| Question | Answer |
|---|---|
| What is the formula for calculating the moment (M)? | Where |
| What unit is force measured in when calculating a moment? | Newtons (N) |
| What unit is perpendicular distance measured in when calculating a moment? | Metres (m) |
| What is the unit for moments derived from force and distance? | Newton-Metre ( |
| A force of | |
| A force of | |
| A person can exert 200N on a plank. The moment needed to snap the wood is |