A Pulley is a simple device consisting of a wheel having a groove along its edge, for holding a cable or rope. These tools are usually used and designed in order to reduce the amount of force needed to lift a load. Although the magnitude of force is reduced, but it must go through a longer distance. The effort needed to pull a load up can be calculated and is roughly equal to the weight of the load divided by the number of wheels. Large number of wheels reduces the efficiency of the system.

Types of Pulley

• Fixed Pulley: This type of pulley has a fixed axle, which is anchored to a place. It is used to redirect the force in a rope.
• Movable Pulley: This type of pulley has a free axle, which is free to move in space. It is used to transform forces.
• Compound Pulley: This type of pulley is a combination of fixed and movable pulley system and thus combines the advantages of both types of pulley.

Use of a Pulley
A pulley is a simple device finding application in diverse fields and areas including:

• Educational Laboratory
• Flag Poles
• Clothes Lines
• Sailboat
• Blinds
• Crane