- Fixed: A fixed pulley has an axle mounted in bearings attached to a supporting structure. A fixed pulley changes the direction of the force on a rope or belt that moves along its circumference. Mechanical advantage is gained by combining a fixed pulley with a movable pulley or another fixed pulley of a different diameter.
- Movable: A movable pulley has an axle in a movable block. A single movable pulley is supported by two parts of the same rope and has a mechanical advantage of two.
- Compound: A combination of fixed and a movable pulleys forms a block and tackle. A block and tackle can have several pulleys mounted on the fixed and moving axles, further increasing the mechanical advantage.
1. Pulley
A pulley is a simple machine that
uses grooved wheels and a rope to raise, lower or move a load.
2. Lever
A lever is a stiff bar that
rests on a support called a fulcrum which lifts or moves loads.
A wedge is an object with at least
one slanting side ending in a sharp edge, which cuts material apart.
A wheel with a rod, called
an axle, through its center lifts or moves loads.
An inclined plane is a slanting
surface connecting a lower level to a higher level.
6. Screw
A screw is an inclined plane
wrapped around a pole which holds things together or lifts materials.
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