A simple machine is a device that can change the direction or the magnitude of a force, or the point where it is applied. This is done so that the force can be used to do work. All mechanical machines are made by combining simple machines.
There are four basic "simple machines":
- The lever (also called a rope or staff) can move the point at which a force is applied and may also change the magnitude and direction of the force.
- The wheel change the direction in which the force is applied
- The pulley changes the point where a force is applied, and may also change its magnitude and direction.
- The inclined plane (also called a wedge)
A compound machine is made up of two or more simple machines.