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NEET 2001 (AIPMT) · Connected Bodies & Pulleys

Connected Bodies & Pulleys question from NEET 2001 (AIPMT)

Q49NEET 2001 · AIPMTEasy

Connected Bodies & Pulleys

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

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Answer: (c)

  1. Useful work (taking g=10 m/s2g = 10\text{ m/s}^2): Wout=mgh=75×10×3=2250 JW_{out} = mgh = 75 \times 10 \times 3 = 2250\text{ J}.
  2. Input work: Win=250×12=3000 JW_{in} = 250 \times 12 = 3000\text{ J}.
  3. η=22503000×100=75%\eta = \dfrac{2250}{3000} \times 100 = 75\%
  4. So the answer is (c) 75%.
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