Work Energy And Power Ques 72
72. A force of $250$ $ N$ is required to lift a $75$ $ kg$ mass through a pulley system. In order to lift the mass through $3 $ $m$, the rope has to be pulled through $12 $ $m$. The efficiency of system is
[2001]
(a) $50 \%$
(b) $75 \%$
(c) $33 \%$
(d) $90 \%$
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Answer:
Correct Answer: 72.(b)
Solution:
- (b) Efficiency $=\frac{\text{ output work }}{\text{ input work }}$
i.e., Efficiency,
$=\frac{75 g \times 3}{250 \times 12}=\frac{75 \times 10 \times 3}{250 \times 12}=0.75=75 \%$
BETA
