Key learning points

1. A force can produce a turning effect known as a moment.
2. If an object is in equilibrium, there is no resultant force or moment on it.
3. moment = force × distance (M = Fd)
4. Levers can act as force or distance multipliers.
5. Gears can be used to transfer moments.

Keywords

• Equilibrium - The state of an object when there is no resultant force or moment acting on it.

• Moment - The turning effect of a force, measured in newton metres (Nm).

• Force multiplier - A type of lever that increases the size of an applied force.

• Distance multiplier - A type of lever that increases the distance an applied force moves through.

• Gears - Toothed wheels that rotate around an axle and are used to transfer moments.

Common misconception