Question

why in a single fixed pulley the velocity ratio is always more than the mechanical advantage

Answer 1

Dear Student,

Let L be the load lifted by an effort E, Such that T is the tension in the rope

Then L = T…..(1)

And E = T……(2)

Or L = E

i.e. L/E = 1

or Mechanical effort = Load/Effort = 1

Let d be the distance through which effort acts, as well as load lifted

Then Velocity Ratio = Distance through which effort moves/Distance through which load moves

Velocity Ratio = d/d = 1

So Mechanical effort = Velocity Ratio

However a part of effort is wasted in moving the single fixed pulley around its axis and due to friction between the rope and pulley. Thus effort is able to lift less load than actual effort applied and hence mechanical advantage is less than 1.

Regards.