Question

A block and tackle system of pulleys has 4 strands of string. When an effort of 50 kgf is
applied, this set up enables us to lift a load of 180 kgf. What is MA, VR and efficiency of
this set up?
​

Answer 1

Answer

Given that,

Load =75kgf

Effort =25kgf

Number of pulleys n=3

We know that,

The mechanical advantage is

M.A=

E

L

M.A=

25

75

M.A=3

Now, the velocity ratio is

Velocity ratio = numbers of pulleys

V.R=3

Now, the efficiency is

η=

V.R

M.A

η=

3

3

η=1×100

η=100%

Hence, this is the required solution