I’ve always seen them on TV, and in professional garages and factories. I know they allow you to lift things far heavier than you normally could. But, how do they actually do that? I have seen that you pull one chain alot and it lifts it a little, so I’m sure that has something to do with it.
In: Engineering
Look on YouTube for SmarterEveryDay’s snatch block video. He’ll describe it better than any one is going to be able to do in text. https://youtu.be/M2w3NZzPwOM
But basically, the rope is all at the same tension, and the pulleys transmit all that tension to the block. So if you pull with 50 units of force, and there’s 6 ropes going to the mobile block, then you’ll have 300 units of force pulling on the block, but have to move the rope 6x the distance that the block will move.
Edit: example ignores friction. So real world block and tackle systems will fall short of the ideal.
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