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A machine is used to lift a load of 20 N through a height of 10 m. if the efficiency of ...

A machine is used to lift a load of 20 N through a height of 10 m. if the efficiency of the machine is 40%, how much work is done?
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  • A 80 J
  • B 500 J
  • C 300 J
  • D 120 J
Correct Answer: Option B
Explanation:
Efficiency = \( \frac{\text{work output}}{\text{work input}} \times \frac{100}{1} \)
= 40 = \( \frac{20 \times 10 }{x} \times \frac{100}{1} \)
= 500J

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