This simple machine is made up of a wheel and a rope. The rope fits on the groove of the wheel. One part of the rope is attached to the load. When you pull on one side of the pulley, the wheel turns and the load will move. Pulleys let you move loads up, down, or sideways.
Pulleys are good for moving objects to hard to reach places.
It also makes the work of moving heavy loads a lot easier. This crane uses a pulley to move the heavy wrecking ball. Without the use of a pulley, the wrecking ball would be very hard to move.