Pulley Essay

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PULLEY – Lessen the force A pulley is a simple machine made with a rope, belt or chain wrapped around a wheel. The pulley is usually used to lift a heavy object. The principle of a pulley is simple. You pull a rope downwards. Because of the way the rope is wound, several sections of the rope pull upwards together. The result is an increased lifting force. A single pulley changes the direction of the lifting force. For example, if you are lifting a heavy object with a single pulley anchored to the ceiling, you can pull down on the rope to lift the object instead of pushing up. The same amount of effort is needed as without a pulley, but it feels easier because you are pulling down. Archimedes was a great mathematician and engineer who was born in 287 BC in Syracuse, Sicily. He is credited with the development of many of our modern day mathematical and mechanical principles and machines like the lever, a pump, and pulleys. Archimedes understood the concept of mechanical advantage and how to use it to move or lift heavy objects with less force. That is, the mechanical advantage of a machine is the ratio of the output and input forces that are used within the machine. For a pulley, the output force is the weight of the object and the input force is the force applied on the end of the rope. Archimedes knew that he could improve his mechanical advantage for lifting or moving an object by using pulleys. So he made this device and it transfers a force along a rope without changing its magnitude. There are three types of pulleys: A FIXED PULLEY, A MOVABLE PULLEY and A COMBINED PULLEY A fixed pulley is the only pulley that when used individually, uses more effort than the load to lift the load from the ground. Also, The fixed pulley when attached to an unmovable object like a ceiling or wall, acts as a first class lever with the fulcrum being located at the axis but with

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