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Line PQ is parallel to y -axis and moment of inertia of a rigid body about P Q line is given by I = 2 x 2 - 12 x + 27 , where x is in meter and I is in k g m 2 . The minimum value of I is:

Options

  1. A27 k g m 2
  2. B11 k g m 2
  3. C17 k g m 2
  4. D9 k g m 2

Correct answer

D. 9 k g m 2

Step-by-step solution

I = 2 x 2 - 12 x + 27 d I d x = 4 x - 12 For minimum or maximum d I d x = 0 ⇒ x = 3 d 2 I d x 2 = 4. Hence I is minimum at x = 3 I = 9 k g m 2

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