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JEE Main 2004 (AIEEE) · Conservation of Energy

Conservation of Energy question from JEE Main 2004 (AIEEE)

Q40JEE Main 2004 · AIEEEEasy

Conservation of Energy

A uniform chain of length 2 m2\text{ m} is kept on a table such that a length of 60 cm60\text{ cm} hangs freely from the edge of the table. The total mass of the chain is 4 kg.4\text{ kg}. What is the work done in pulling the entire chain on the table?

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Answer: (b)

  1. Mass of hanging part: m=42×0.6=1.2 kgm = \frac{4}{2} \times 0.6 = 1.2\text{ kg}; its centre of mass is 0.3 m0.3\text{ m} below the edge.
  2. W=mgl2=1.2×10×0.3W = mg\frac{l}{2} = 1.2 \times 10 \times 0.3
  3. W=3.6 JW = 3.6\text{ J}
  4. So the answer is (b) 3.6 J3.6\text{ J}.
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