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Question
A block and tackle system has V.R. = 5.
Rohan exerts a pull of 150 kgf. What is the maximum load he can raise with this pulley system if its efficiency = 75%?
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Solution
Given: Velocity ratio, VR = 5
Effort = 150 kgf
Efficiency = 75%
We know that efficiency, `eta = "Mechanical Advantage"/"Velocity Ratio"`
`75/100 = "MA"/5`
`Ma = 5 xx 75/100`
∴ Mechanical advantage = 3.75
But, Mechanical advantage = `"Load(L)"/"Effort(E)"`
∴ Load = Mechanical advantage x Effort
= 3.75 × 150 Kgf
= 562.5 Kgf
Therefore, Rohan can raise a maximum load of 562.5 kgf with this pulley system.
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