The moment is the turning effect of a force.

moment about O = F l

where: | |||

symbol |
description |
type |
units |

moment | effort | bivector | Nm=newton-metre=kg*m^{2}/s^{2} |

F | Force | vector | N=newton=kg*m/s^{2} |

l | perpendicular distance from pivot | vector | m |

moment = F y

A moment is a force multiplied by the perpendicular distance from a pivot or falcrum, the units of a moment are Newton-metres (N m). For equilibrum:

moments clockwise = moments anticlockwise

### Example

Find the reactions of the beam shown:

Take moments about R1, for equilibrium,

moments clockwise = moments anticlockwise

2500*1 + 5000*7 = R2*10

R2 = 3750N

forces acting down = forces acting up

2500 + 5000 = R1 + 3750

R1 = 3750 N