Clockwise and Anticlockwise Moments
It is important to be able to distinguish between clockwise and anticlockwise moments because the net moment = anticlockwise - clockwise tells us in which direction a system will turn.
If anticlockwise - clockwise > 0 the system will turn clockwise
If anticlockwise - clockwise < 0 the system will turn anticlockwise
If anticlockwise = clockwise < 0 the system will not turn
a force has a clockwise or anticlockwise moment relative to a point. If we move the point to take moments about the sense of the moment may change from clockwise to anticlockwise or vice versa.
Taking moments about the pivot O, we can label the forces in the diagram below as clockwise or anticlockwise by imagining a clockface at O. The force which make the horizontal beam turn down to the right, in the direction the clock hands would move, are labelled clockwise and the forces which would make the beam turn in the opposite direction are labelled anticlockwise. The 50 N force is clockwise and the forces 10 N, 15N and 25 N are anticlockwisre.
If we move the pivot point we have to relabel the forces as clockwise or anticlockwise, relative to the new balance point. All the forces in the diagram below are anticlockwise forces.