Completar frases PULLEYSVersión en línea Fill the gaps por jose tisner 1 easier supplies hang load pulley pull muscle force weight pounds flag rope elevators wheel machines Suppose you needed to lift something , and there weren't any simple to help you . You have only your own muscles to rely on to do work . The stronger you were the it would be . If you were so strong , you might try to think of something to help you . A rope passed over a branch might help make the work easier . But it would also have its problems reply actions for instance . To solve this problem you might think using a , one with a groove on it mounted , so it can turn and so you can hang it from something . When a is passed over this , it can move with much less friction and it can scraping over a stretch . The groove in the wheel keeps the rope from slipping off . The whole arrangement , the wheel and the rope that goes over it is called a . Pulleys are simple machines that help people do work . This one is a fixed pulley because it stays in one place as you use it . How does a fixed pulley make lifting things easier ? Suppose you attach a or a load here . Up or down on your end of the rope causes up or on the other end . You apply a in one place and that produces a force in another place to lift the load . The amount of force you apply is the same as the force that act on the load . If the load weighs 25 then you have to pull down with the forces 25 pounds in order to lift it and if it weighs 50 pounds on . You have to pull down with fifty pounds of force same amount of force you need to lift the without the pulley . So , affixed pulley does not increase your force , it helps you left things by changing the direction of force . It allows you to down in order to lift something up , for instance if you want to raise a flag up a pole you don't have to climb the pulley and pull it up . You can put a fix pulley at the top and raise the without leaving the ground . And if you look the rope around a second fixed pulley a bottom , you can also pull the flag down . If you left something by pulling it up only your do the work When you pull down your own way can help you . Using your own weight as a force you can raise something that weighs less than you do . But not something that weighs more , but with a pulley you don't have to use only your own weight . Suppose you want to lift something that weighs 100 pounds . You could another weight , a counterweight , and you at the end of the rope . If the counterweight weighs 90 pounds that would lift the load but all you have to the difference , 10 pounds of force , and you could lift it . Fixed pulley and counterweights are often used in lifting machines like .
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