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Question
A single fixed pulley and a movable pulley both are separately used to lift a load of 50 kgf to the same height. Compare the efforts applied in an ideal situation.
Solution
In case of a single fixed pulley, the effort (Ef needed to lift a load) is equal to the load itself.
Thus, Ef = L
→ Ef = 50 kgf
In case of a single movable pulley, the effort needed to lift a load is equal to half the load.
→ Em = `"L"/2`
→ Em = `("50 kgf")/2` = 25 kgf
Thus, the ratio of efforts applied by the respective pulley is
`"E"_"f"/"E"_"m" = 2/1`
`"E"_"f" : "E"_"m"` = 2 : 1
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