Question

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.

Answer 1

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 (E_{single fixed pulley})  = `"Load"/(MA_"single fixed pulley")`

= `50/1 = 50` kgf

Effort (E_{single 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.