What is a lever?

A lever is a simple machine consisting of a rigid bar or beam that is able to pivot or rotate around a fixed point called a fulcrum. Levers are used to amplify force or to lift heavy objects with less effort by applying a smaller force over a longer distance. There are three classes of levers based on the relative positions of the fulcrum, effort (input force), and load (output force).

A lever is a simple machine that consists of a rigid bar pivoted on a fixed point, called a fulcrum. The lever is used to amplify an input force to produce an output force that is greater than the input force.

Levers are classified into three types, depending on the relative positions of the fulcrum, the input force, and the output force. The three types of levers are:

- First-class lever: The fulcrum is located between the input force and the output force. Examples of first-class levers include the seesaw and the crowbar.
- Second-class lever: The input force is located between the fulcrum and the output force. Examples of second-class levers include the wheelbarrow and the nutcracker.
- Third-class lever: The output force is located between the fulcrum and the input force. Examples of third-class levers include the tweezers and the fishing rod.

Levers are used in a wide variety of applications, including construction, manufacturing, and transportation. Levers can be used to lift heavy objects, open doors, and change the direction of a force.