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Manipal MET2020PhysicsRotational Motion

A rod of length L is composed of a uniform length L 2 of wood whose mass in m_w and a uniform length L 2 of brass whose mass is m_b . The moment of inertia / of the rod about an axis perpendicular to the rod and through its centre is equal to

Options

  1. A(m_w+m_b ) L^2 6
  2. B(m_w+m_b ) L^2 2
  3. C(m_w+m_b ) L^2 12
  4. D(m_w+m_b ) L^2 3

Correct answer

C. (m_w+m_b ) L^2 12

Step-by-step solution

For a thin uniform rod, moment of inertia about an axis through its centre perpendicular to length of rod, I= 1 12 M L^2 Here, M= (m_w+m_b ) A I= 1 12 (m_w+m_b ) L^2

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