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
- 300N
- 200N
- 140N
-
120N
The correct answer is: D
Explanation
M.A = \(\frac{E \times V.R}{100} = \frac{40 \times 6}{100} = \frac{12}{5}\)W = M.A x effort
= \(\frac{12}{5} \times 50 = 120N\)