Simple machines - pulleys that change force, direction and rotations.

Pulleys that change: -the direction and magnitude of the applied force; - speed.
We can connect pulleys to each other with a belt and have one pulley drive the other. In this manner we can magnify the force, increase the number of turns or change the direction of the force applied. For example, have a look at the diagram on the right, pulley "A" being twice as big as pulley "B" increases the rate of rotation of pulley "B" two fold.
The pulley system on the left shows pulley "A" increasing the number of rotations of pulley "B" but in the opposite direction. Forces can be magnified or reduced by using pulleys.
Forces can be magnified or reduced by using pulleys. Larger pulleys exert a greater force than smaller pulleys. Pulley "B" is the driving pulley, usually connected to a motor, while pulley "A" is the driven pulley. Pulley "A" is twice the size of pulley "B" and therefore exerts a force twice that applied by pulley "B" eventhough it rotates half as fast.
Machines are devices that multiply force or simply change the direction of the force. During the 1800s pulleys were used to transfer force around the workshop. Pulleys were used to multiply and change the direction of the force.
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