Question

Give two reasons why the efficiency of a single movable pulley is not 100% .

Answer 1

Hint: The above problem can be resolved by applying the concept of the frictional force and its applications in the field of mechanics and machine elements. The single movable pulley is used for various purposes, for which friction is one of the factors affecting its effectiveness.


Complete step-by-step answer
The single movable pulley is one of the basic mechanical elements that is used for the purpose to transfer forces from one mechanical component to another mechanical component. The efficiency of the single movable depends on the friction between the pulley and the string or rope attached with the pulley, to cause the force transmission.
The reason for not achieving the efficiency by the pulley are as follows:
1. There should be always some friction between the pulley and the string. Absence of friction may resist the force transmission and in turn can cause inefficiency of the pulley.
2. Another important parameter for the inefficiency of pulley is weightlessness of the string, connected with the pulley. There should be some weight of string, so that it can hold the pulley to create some friction and let power transmission be achieved properly.


Note: In order to resolve the given conditions, one must be clear regarding the basic concepts of friction and its application. Moreover, it is important to go through the working construction and the factors affecting the efficiency and its performance.