Question

The mechanical advantage of an actual pulley is less than 1. Give a reason. What is the justification for using the pulley then?

Answer 1

In an actual pulley due to friction, the mechanical advantage is less than 1 ( i.e. the effort is more than the load).

The reason for using the pulley when its mechanical advantage is equal to 1 or less than 1 is that the pulley allows us to apply the effort downwards i.e.. in a convenient direction. To raise a load directly upwards is difficult. But with the help of a pulley, the effort can be applied in the downward direction to move the load upwards. One can hang on it to make use of his own weight also, in order to apply the effort.