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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
