# A Boy Uses a Single Fixed Pulley to Lift a Load of 50 Kgf to Some Height. Another Boy Uses a Single Movable Pulley to Lift the Same Load to the Same Height. Compare the Effort Applied by Them. Give a Reason to Support Your Answer. - Physics

A boy uses a single fixed pulley to lift a load of 50 kgf to some height. Another boy uses a single movable pulley to lift the same load to the same height. Compare the effort applied by them. Give a reason to support your answer.

#### Solution

The ratio of load to the effort is called the mechanical advantage.

Mechanical advantage (MA) = "Load(l)"/"Effort(E)"

The above equation indicates that 'MA' and 'Effort' are inversely proportional.

The mechanical advantage of the single fixed pulley is 1.

For, single movable pulley = 50 kgf

:. Effort (Esingle fixed pulley)  = "Load"/(MA_"single fixed pulley")

= 50/1 = 50 kgf

Effort (Esingle fixed pulley) = "Load"/(MA_"single movable pulley")

= 50/2 = 25  kgf

Therefore, the boy using a single movable pulley requires lesser effort to lift an equal load of 50 kgf when compared with the effort required by the boy using a single fixed pulley.

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