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.

Answer 1

In case of a single fixed pulley, the effort (E_f needed to lift a load) is equal to the load itself.

Thus, E_f = L

→ E_f = 50 kgf

In case of a single movable pulley, the effort needed to lift a load is equal to half the load.

→ E_m  = `"L"/2`

→ E_m  = `("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