The diagram above illustrates a block ans tackle pulley system in which an effort E supports a load of 100.0N. If the efficiency of the machine is 75%, calculate the value of E
Attached Figure / Diagram
A
22.2N
B
38.0N
C
67.0N
D
75.0N
Verified Correct Answer: A.
Physical Principles & Numerical Solution
Given; VR = 6, e = 75%, MA = ?
e = \(\frac{\text{MA}}{\text{VR}} \times \frac{100}{1}\)
MA =\(\frac{75 \times 6}{10}\)
MA = \(\frac{9}{2}\)
MA = \(\frac{L}{E} = \frac{100}{E}\)
\(\frac{9}{2} = \frac{100}{E}\)
9E = 100
E = \(\frac{200}{9}\)
= 22.2N
Source: Myschool Past Questions Archive (Record #45449)