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Question
A block and tackle system has the velocity ratio 3. Draw a labelled diagram of the system indicating the points of application and the directions of load L and effort E. A man can exert a pull of 200 kgf. What is the maximum load he can raise with this pulley system is its efficiency is 60%?
Solution
E = `L/(n ("number of pulleys"))`
200 = `L/3`
∴ L = 600 kgf
But efficiency = 60 %
= `60/100 xx 600`
= 360
Maximum load that can be raised = 360 kgf
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