Kinds of Simple Machines

Pulley

A pulley is a simple machine with grooved wheels and a rope. It is used to raise, lower, or move things. This simple machine reserves the direction of a force. Less force is exerted in lifting an object when more pulleys are used.

In a pulley, a cord is placed around a wheel. The cord moves in the opposite direction as the wheel rotates. A hook attached to the cord helps raise and lower objects. Pulleys are very helpful machines used by workers in construction sites. They help move heavy objects from the ground to a higher place.

On a flagpole, you will see a rope attached to a pulley. On the rope, you will find two hooks. As the cord rotates around the pulley, the hooks are lowered. The flag is attached to these hooks. The flag moves up the pole as the cord is pulled.