| A | B |
|---|
| centre of gravity | The point at which all the weight of a body appears to act |
| What are the three states of equilibrium? | Stable, unstable, neutral |
| High centre of gravity and narrow base | unstable |
| Low centre of gravity and broad base | stable |
| Effort | The force used to move a lever |
| Lever | A rigid body which is free to turn about a fixed point called the fulcrum |
| Formula for Moment of a Force | Force x Perpendicular distance from the fulcrum to the line of action of the force |
| Law of the Lever | When a lever is balanced the sum of the clockwise moments is equal to the sum of the anticlockwise moments |
| A body is in Stable equilibrium | tilting it slightly raises its centre of gravity |
| unstable equilibrium | if tilting it slightly lowers its centre of gravity |
| Neutral equilibrium | Moving it slightly does not change the height of the centre of gravity |
| Point of equilibrium | where all the forces acting on a body cancel each other out |
| moment of force | the turning effect of the force |
| What is the principle of stable design? | a low centre of gravity and a wide base |
