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NEET 1990 (AIPMT) · Rotational Kinetic Energy, Work & Power

Rotational Kinetic Energy, Work & Power question from NEET 1990 (AIPMT)

Q54NEET 1990 · AIPMTEasy

Rotational Kinetic Energy, Work & Power

A fly wheel rotating about fixed axis has a kinetic energy of 360 joule when its angular speed is 30 radian/sec. The moment of inertia of the wheel about the axis of rotation is

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Answer: (c)

  1. K=12Iω2⇒I=2Kω2K = \frac{1}{2}I\omega^2 \Rightarrow I = \frac{2K}{\omega^2}
  2. I=2×360302=720900=0.8I = \frac{2 \times 360}{30^2} = \frac{720}{900} = 0.8 kg m2^2
  3. So the answer is (c) 0.8 kg m20.8\text{ kg m}^2.
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