Pivot

Think of pushing a door: the hinges form the pivot, and a push at the handle can rotate the door around them. Other examples include a child turning a seesaw about its central support or a force on a spanner turning a nut.

Rotation means turning around a fixed point or axis, called the pivot. A door turns around its hinges; a wheel turns around its axle. The turning effect of a force about a pivot is called a moment.

The point an object turns around is its pivot. The hinges act as the door’s pivot, while the support is the seesaw’s pivot.

A force whose line of action passes through a pivot does not produce a turning effect about that pivot. When the line of action misses the pivot, the force can make the object rotate. The turning effect is called the moment of the force.