If the object is balanced: total clockwise moment = total anticlockwise moment. The diagrams show two examples of balanced objects where there is no rotation.
A ball at the bottom of a trough
A balanced see-saw
An object in equilibrium will not turn or accelerate - there is no overall (resultant) force and the clockwise moments are equal to the anticlockwise moments.
For a balanced object, you can calculate:
A parent and child are at opposite ends of a playground see-saw. The parent weighs 750 N and the child weighs 250 N. The child sits 2.4 m from the pivot. Calculate the distance the parent must sit from the pivot for the see-saw to be balanced.
child's moment = force × distance
250 N × 2.4 m = 600 Nm
Parent's moment = child's moment
Rearrange to find d for the parent:
Then calculate using the values: