Pulley is a wheel with hollow sections along the sides for a rope or cable. Pulleys are usually used in a circuit that is designed to reduce the amount of force needed to lift a load. However, the amount of work done to make the load reaches the same height is the same as that required without the use of pulleys. The force is reduced, but the style has to work over longer distances. Effort required to lift a load is roughly equal to the weight of the load divided by the number of wheels. The more wheels there, the system less efficient. because there will be more friction between the rope and wheels. Pulley is one of the six types of simple plane.
Found no record of when and by whom the pulley was first developed, but of possible be from Eurasia. The base-forming system of pulleys, wheels, was found some time after the discovery of Eurasia to the community in the western hemisphere, sub-Saharan Africa, and Australia. Also believed that Archimedes developed the first series of pulley system, as recorded by Plutarch where.
Single fixed pulley
Style your muscles while raising the bucket with rope pulled upward force equal to your muscles when pulling the rope down through the single pulley fixed.
Single fixed pulley work to change the direction of gravity pull up to pull down. When you draw water without going through the pulley, you have to pull the rope up. Vertical direction of the force is your weight down. Because the direction of the force tarikmu "opposite" the direction of your weight, your muscle force when pulling the rope to the top was not helped by the force of your weight. Therefore, the work of raising heavy bucket.
Fixed pulley KM = 1
Pulleys move KM = 2
Compound pulley KM = n (n = number of pulleys)
KM = Mechanical Advantage