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NEET 1994 (AIPMT) · Work by a Variable Force

Work by a Variable Force question from NEET 1994 (AIPMT)

Q25NEET 1994 · AIPMTEasy

Work by a Variable Force

A position dependent force, F=(7−2x+3x2) NF = (7 - 2x + 3x^2)\text{ N} acts on a small body of mass 2 kg2\text{ kg} and displaces it from x=0x = 0 to x=5 mx = 5\text{ m}. The work done in joule is

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Answer: (a)

  1. W=∫05(7−2x+3x2) dx=[7x−x2+x3]05W = \int_0^5 (7 - 2x + 3x^2)\,dx = \left[7x - x^2 + x^3\right]_0^5
  2. W=35−25+125=135W = 35 - 25 + 125 = 135 J (mass is not needed)
  3. So the answer is (a) 135.
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