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Question
In a block and tackle system consisting of 3 pulleys, a load of 75 kgf is raised with an effort of 25 kgf. Find:
- the mechanical advantage,
- velocity ratio and
- efficiency.
Solution
Load = 75 kgf
Effort = 25 kgf
∴ n = 3
M.A. = `"Load"/"Effort"`
M.A. = `75/25`
M.A. = 3
or MA = n = 3
Velocity ratio VR = n = 3
Efficiency η = `"M.A."/"V.R."= 3/3` = 1 or 100%
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