The diagram above is a block and tackle pulley system in ...
The diagram above is a block and tackle pulley system in which an effort of 80N is use to lift a load of 240N. The efficiency of the machine is
A.
60%
B.
50%
C.
40%
D.
33%
Correct answer is B
Since the number of pulleys present is 6, it implies that the velocity ratio VR = 6
| ∴ efficiency = | M.A |
| |||
| V.R |
= Load/Effort x 1/V.R x 100/1
= 240/80 x 1/6 x 100/1
= 50%
∴ Efficiency = 50%