Using a pulley can change the way force and distance are related when lifting an object. To understand how these values change, it’s important to clarify the type of pulley you are using.
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Fixed Pulley: This type of pulley does not change the amount of force needed to lift the weight; it only changes the direction of the force. Thus, you still need to exert 400 Newtons to lift the weight over the same distance (4 meters). However, if you pull down on the rope, the weight is lifted up by the same distance, which can be more convenient.
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Movable Pulley: If a movable pulley is used, it can reduce the amount of force needed to lift the weight. With a movable pulley, you typically reduce the force required to lift the weight by half, assuming no friction. Therefore, you would only need to exert 200 Newtons to lift the 400 Newton weight, but you would need to pull the rope twice the distance of the lift (8 meters) to raise the weight 4 meters.
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Block and Tackle System: If you have a system of multiple pulleys (block and tackle), the force required can be further reduced depending on how many segments of rope support the weight. For example, with four segments supporting the weight, you need to exert only 100 Newtons, but you would need to pull 16 meters of rope to lift the weight 4 meters.
In summary:
- Fixed Pulley: Force = 400 N, Distance = 4 m
- Movable Pulley: Force = 200 N, Distance = 8 m
- Multiple Pulleys: Force = 100 N (for 4 segments), Distance = 16 m
The exact values depend on the pulley configuration used.
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