Supercharge your learning!

Use adaptive quiz-based learning to study this topic faster and more effectively.

Moments as turning effect of forces

The moment of a force is the turning effect of a force.

A worker applies a force to a spanner to turn a nut.

A force that is applied to an object away from the object's centre makes the object rotate about a fixed point.

The point of an object that does not change position when it experiences a moment is the pivot.

A moment is a vector quantity because it has a size and a direction. Moments can act clockwise or anti-clockwise.

When you open a door the pivot is the hinge which connects the door to the wall. The force is you pushing the door.

For a seesaw the pivot is the central part which is connected to the ground. The force is the weight of the person sitting on the seesaw.

Both the girl and the boy apply a moment to the seesaw causing it to rotate.
Both the girl and the boy apply a moment to the seesaw causing it to rotate.