JAMB - Physics (1986 - No. 43)
fig 4 represents a block-and-tackle pulley system on which an effort of W newtons supports a load of 120.0N if the efficiency of the system is 40% then the value of W is
28.0N
48.0N
50.0N
288.0N
Explanation
Efficiency = \(\frac{M.A×100}{V.R}\)
V.R = 6
40= \(\frac{M.A×100}{6}\)
M.A = \(\frac{6 ×40}{100}\)
M.A = 2.4
M.A= \(\frac{L}{E}\)
E= \(\frac{120}{2.4}\)
E = 50
V.R = 6
40= \(\frac{M.A×100}{6}\)
M.A = \(\frac{6 ×40}{100}\)
M.A = 2.4
M.A= \(\frac{L}{E}\)
E= \(\frac{120}{2.4}\)
E = 50
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