Question

The mechanical advantage of an ideal single movable pulley is:

(a) 1 

(b) 2 

(c) less than 2 

(d) less than 1

Answer 1

The mechanical advantage of an ideal single movable pulley is 2.

Derivation: Consider the diagram given below:

Here the load L is balance by the tension in two segments of the string and the effort E balances the tension T at the free end, so

L = T + T = 2T and E = T

Assumption: Weight of the pulley is negligible.

We know that,

M.A = Load (L)/Effort (E) = 2T/T = 2

Thus, a single movable pulley has a M.A. equal to 2.