Pulley system with one mass and apparently independent forces?

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SUMMARY

The discussion centers on a cable machine at a gym that utilizes a pulley system where pulling on one cable lifts a mass with a consistent force, regardless of whether one or both cables are engaged. Each cable requires the same force (y) to lift the mass (x), leading to the conclusion that the system is designed to maintain equal tension in the cables. This design allows users to pull on both cables without increasing the perceived weight, demonstrating the principles of mechanical advantage and tension in pulley systems.

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Maurice7510
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So at my gym, there's a cable machine that works like this: You pull on one cable and you lift x mass using y force. You pull the other and find the same thing. If, however, you pull on both, you're still only lifting x mass (you can see the weights) yet somehow each cable is still requiring y force. I actually held ~80lbs in both arms, and then released one. Intuitively, I should then be resisting 160lbs with one arm, which aside from being well beyond my ability, should have at least been noticeable. Yet I found no noticeable difference at all.
I was just wondering how a system could be set up to allow for this kind of thing.
 
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Maurice7510 said:
You pull on one cable and you lift x mass using y force. You pull the other and find the same thing. If, however, you pull on both, you're still only lifting x mass (you can see the weights) yet somehow each cable is still requiring y force.

See the pulley on the right:



The forces in the cables are equal, and stay the same no matter if you pull one of them or both.
 
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