To lift a load of 30 kgf, Suhas uses a single fixed pulley while Radha uses a single movable pulley. The displacement of efforts in both the cases are equal. In an ideal situation calculate the ratio of :
the efforts in the two cases.
Topic: Mechanical advantage of pulleys
Answer
Given: load = 30 kgf, both pulleys ideal.
For an ideal single FIXED pulley, MA = 1: effort = load ÷ MA = 30 ÷ 1 = 30 kgf (Suhas)
For an ideal single MOVABLE pulley, MA = 2: effort = load ÷ MA = 30 ÷ 2 = 15 kgf (Radha)
Ratio of the efforts: Suhas : Radha = 30 : 15 = 2 : 1
Ratio of the efforts = 2 : 1
The two mechanical advantages are worth knowing by heart: an ideal fixed pulley has MA = 1 and an ideal movable pulley has MA = 2.
A fixed pulley gives you no force advantage at all — it only changes the DIRECTION of the effort, which is convenient because you can pull downwards using your own weight. A movable pulley has two strands supporting the load, so each carries half of it and the effort is halved.
Keep the order the question asks for. Suhas uses the fixed pulley, so his effort comes first: 2 : 1, not 1 : 2.