A block and tackle has two pulleys in each block with the tackle tied to the hook of the lower block and the effort being applied upwards.
(a) Draw a neat diagram to show this arrangement and calculate its mechanical advantage.
(b) If the load moves up by a distance x, by what distance will the free end of the string move up?

Question

KnowledgeBoat · Accepted Answer

(a) The arrangement is shown in the figure given below :

Here, the load is being supported by five segments of the string.

∴ L = 5T and E = T

Then,

M.A. = $\dfrac{\text{L}}{\text{E}}$

= $\dfrac{\text{5T}}{\text{T}}$ = 5

∴ Mechanical advantage of the system is 5.

(b) In an ideal block and tackle system, if n segments of rope support the load, then the total length of the rope pulled = n × x.

As, here the load is being supported by five segments of the string then if the load moves up a distance x,

then,

Free end of the string will move up by a distance = 5x

Physics