WAEC - Physics (2015 - No. 17)

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
22.2N
38.0N
67.0N
75.0N

Explanation

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

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