Science · 6 pages · 12 min
How a pulley spends distance to save force
Each extra supporting strand halves the pull and doubles the rope you haul.
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From the opening
A pulley saves force by sharing a load among several strands of rope, so each strand carries only a fraction of the weight. You pay by hauling more rope than the load actually rises. The opening covers fixed pulley versus moving pulley, counting the supporting strands, and why you pull more rope.
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Inside
- Fixed pulley versus moving pulley
- Counting the supporting strands
- Why you pull more rope
- What sheave friction takes back
- Where the idea stops applying
- A distinction worth keeping
Sources
- Mechanical advantage of a block and tackle
- The distinction between a fixed and a movable pulley