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
A.
300N
B.
200N
C.
140N
D.
120N
E.
20N
Correct answer is D
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