Question

From the diagram given below, answer the questions that follow :
(i) What kind of pulleys are A and B?
(ii) State the purpose of pulley B.
(iii) What effort has to be applied at C to just raise the load L = 20 kgf?
(Neglect the weight of pulley A and friction).

Answer 1

(i) A - Single Movable Pulley, B - Single Fixed Pulley.
(ii) To change the direction of force applied i.e., effort can be applied in a more convenient direction.
(iii) Given: $L=20kgf$
In equilibrium, $L=2T$ and Effort $E=T$
$\therefore$ Effort needed, $E=\frac{L}{2}$
$=\frac{20kgf}{2}$
$=10kgf$