Moments

The moment of an object is the objects turning force. If you are trying to undo a nut with a spanner the moment can be increased by:

• Increasing the size of the force (applying more force)
• Using a spanner with a longer handle (makes it easier)

The longer the spanner handle the easier it is to undo the nut. This is because the longer the spanner handle, the less force you need to exert on it to untighten the nut.

You can work out the moment of a force by using this equation:

Moment   =   Force   x   perpendicular distance from the line of action of the force

(Newton        (Newtons)                            (Metres)

metres) (Nm)     (N)                                     (m)

Worked Example

A force of 50N is exerted on a claw hammer of length 0.30m. Calculate the moment of the force.

Solution

Force = 50N x 0.30m = 15Nm