A block and tackle system has six pulleys. a force of 50N applied to it lifts a load of weight W. If the efficiency of the system is 40%, calculate W
A
300N
B
200N
C
140N
D
120N
Verified Correct Answer: D.
Physical Principles & Numerical Solution
M.A = \(\frac{E \times V.R}{100} = \frac{40 \times 6}{100} = \frac{12}{5}\)
W = M.A x effort
= \(\frac{12}{5} \times 50 = 120N\)
Source: Myschool Past Questions Archive (Record #34659)