How do levers utilise the turning effect of forces?

Levers utilise the turning effect of forces by amplifying the force applied at one end to move a load at the other.

A lever is a simple machine that consists of a rigid bar pivoted on a fixed point, known as the fulcrum. The turning effect of forces, also known as torque, is utilised in a lever system to make work easier. This is achieved by changing the distance from the fulcrum at which the force is applied.

The principle of levers is based on the law of moments, which states that for a system to be in equilibrium, the sum of clockwise moments about any point must be equal to the sum of anticlockwise moments about the same point. In the context of a lever, the moment is the product of the force applied and the distance from the fulcrum at which the force is applied.

When a force is applied at one end of the lever, it creates a turning effect or moment around the fulcrum. This turning effect is then transferred to the other end of the lever, where it can move a load. The advantage of using a lever is that it allows a small force to move a large load. This is because the force applied is amplified by the distance from the fulcrum, allowing a small input force to generate a large output force.

For example, consider a seesaw in a playground. When a child sits on one end of the seesaw, they apply a force downwards due to their weight. This creates a moment about the fulcrum, causing the seesaw to rotate and lift the child on the other end. The further the child sits from the fulcrum, the greater the moment they create and the higher the other child is lifted. This demonstrates how levers utilise the turning effect of forces to make work easier.