Question

The mechanical advantage of an ideal single fixed pulley is and of an ideal single movable pulley is .

• A. 4
• B. 3
• C. 2
• D. 1

Answer 1

Answer: (C), (D)

The correct options are
C 2
D 1

A pulley which has its axis of rotation unchanged, is called a fixed pulley.

In equilibrium, L = T and E = T (when pulley is not rotating)
$⟹$E = L
Mechanical advantage $=\frac{\text{L}}{\text{E}}=1$

A single movable pulley ideally acts as a force multiplier.
L = T + T = 2T, E = T
M.A. = $\frac{\text{Load}}{\text{Effort}}$ = $\frac{2\text{T}}{\text{T}}=2$
M.A. in ideal case = 2
Using an ideal single movable pulley, the load can be lifted by applying an effort equal to half the load.