Question

The alongside figure shows the combination of a movable pulley P₁ with a fixed pulley P₂ used for lifting up a load W.

(i) State the function of the fixed pulley P₂ . 

(ii) If the free end of the string moves through a distance x, find the distance by which the load W is raised. 

(iii) Calculate the force to be applied at C to just raise the load W = 20kgf, neglecting the weight of the pulley P₁ and friction. 

Answer 1

(i) It is quite difficult to apply effort in the upward direction, if no fixed pulley P₂ is used. The fixed pulley changes the direction of effort from upwards to downwards, making the application of the effort more convenient and easier.