The diagram represents a block-and-tackle pulley system on which an effort of 50N is just able to lift a load of weight W. If the efficiency of the machine is 40%. find the value of W
Attached Figure / Diagram
A
300N
B
200N
C
140N
D
120N
E
20N
Verified Correct Answer: D.
Physical Principles & Numerical Solution
Eff = \(\frac{MA}{VR}\) x 100%
40 = \(\frac{MA}{60}\)
MA = 240
\(\frac{L}{E} = \frac{240}{100}\)
W = L = \(\frac{240}{100}\) x 50
= 120N
Source: Myschool Past Questions Archive (Record #33211)