pulleys and gears
Pulleys and gears are used to transfer rotary motion from one place to another. Both are wheels. Pulleys are wheels with grooves in the rims, in which a belt or rope can run. Pulleys can transfer rotary motion from one shaft to another or can be used to lift heavy loads.
Gears are wheels with teeth evenly spaced around the rims. Several gears can be placed, so that their teeth interlock, or mesh. When two or more gears are used together, they form what is called a gear train. Gears can be used to change the speed and direction in which something rotates. When chains are used to connect the “gears”, a chain and sprocket system is formed, for example on bicycles and motorcycles.Simple pulley