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Work, Energy and Power
Work and Efficiency of Machines
1 question from 1 paper, each with its answer.
- question
- 1
- paper
- 1
- of Work, Energy and Power
- 1.41%
Concepts tested
- Efficiency of a pulley system
All Questions
2001 AIPMT 1 question
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250 N force is required to raise 75 kg mass from a pulley. If rope is pulled 12 m then the load is lifted to 3 m, the efficiency of pulley system will be : -Efficiency $\eta = \dfrac{\text{useful work}}{\text{total work}} = \dfrac{mgh}{F \times d}$
Useful work $= 75 \times 10 \times 3 = 2250$ J (taking g = 10 m/s$^2$)
Total work done by the effort $= 250 \times 12 = 3000$ J
$\eta = \dfrac{2250}{3000} = 0.75 = 75$ percent