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Pulleys. |
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| Pulleys are extremely useful for lifting objects. Most machines used for lifting, such as cranes, have sets of pulleys that magnify the effort. We will use the words effort to mean the force needed or applied and load to mean the weight that needs to be lifted. The more pulleys that are used the less effort required to lift the load and the slower the load is lifted off the ground. |
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Sailing ships use pulleys to
lift the heavy sails up the mast. A six pulley system meant that a sailor
weighing 80 kilograms can lift a sail 6 times the weight of the sailor (480
Kg). Lifting cargo into the haul of the ship was heavy work made increasingly
lighter by the use of pulleys. |
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