Pulleys and Levers
A pulley works like a lever. You can use them to reduce the force needed to move an object but the payoff is that you need to pull more rope through the pulley or move the end of the lever further.
Force x Distance = Word Done (which is the same as energy, which can't be created or destroyed)
So if you arrange the rope to go around the pulleys such that there are 4 lengths of rope that get shorter when the load moves up (both of these diagrams are the same arrangement) we will need to shorten the rope by 4 times the distance the load moves up. So the force on the rope will be a quarter of the load. The quarter load balances the 4 times distance.
A pulley works like a lever. You can use them to reduce the force needed to move an object but the payoff is that you need to pull more rope through the pulley or move the end of the lever further.
Force x Distance = Word Done (which is the same as energy, which can't be created or destroyed)
So if you arrange the rope to go around the pulleys such that there are 4 lengths of rope that get shorter when the load moves up (both of these diagrams are the same arrangement) we will need to shorten the rope by 4 times the distance the load moves up. So the force on the rope will be a quarter of the load. The quarter load balances the 4 times distance.
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