cmars
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- TL;DR Summary
- If a load (a person - 200 lbs.) is on a rope tied in with a knot and the rope goes up to a fixed pulley and back down to the persons hands and he hauls. What is the mechanical advantage in that system?
The rope is tied into the person (the load of 200 pounds) and the rope goes up from the person to a fixed pulley and back down to his hands. He hauls the rope to suspend himself in the air. What is the mechanical advantage of the system? The person will indeed only have to lift half of his body weight (roughly 100 pounds) because he now lessened the load by that same amount. This APPEARS to be a 2:1 because he can hold himself with half the force, but my question is: is that mechanical advantage or is he just equalizing tension on both sides and it’s still a 1:1 MA.
This has been a highly debated topic in my fire department that does technical rescue. I need a real physicist to examine the numbers and system and explain why it is a 2:1 or 1:1.
This has been a highly debated topic in my fire department that does technical rescue. I need a real physicist to examine the numbers and system and explain why it is a 2:1 or 1:1.