Question

The given figure shows a block and tackle system of pulleys used to lift a load. When the load pulled up by a distance 1m, how much do the effort end move?

• A. 2 m
• B. 4 m
• C. 6 m
• D. 8 m

Answer 1

The correct option is B

4 m

There are four strands of tackle supporting the load.

If the load attached to the system is L, effort applied at free strand is E and the number of pulleys (n) = 4.
Then in equilibrium, L = 4T and E = T.
$\therefore$ Mechanical advantage $=\frac{L}{E}=\frac{4T}{T}=4$

Here, velocity ratio = number of pulleys
$\therefore$ VR $=\frac{Distancemovedbyeffort}{Distancemovedbyload}$
or $4=\frac{Distancemovedbyeffort}{1}$

Hence ,distance moved by effort end is 4 m.