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Most Important Selected Qs for JEE AdvancedPhysicsRotational Motion

A light rigid rod A B of length 3 has a point mass m at end A and a point mass 2 m at end B is kept on a smooth horizontal surface. Point C is the center of mass of the system. Initially the system is at rest. The mass 2 m is suddenly given a velocity v ₀ towards right. Take Z axis to be perpendicular to the plane of the paper.

Options

  1. AThe minimum moment of inertia (about Z -axis), I _ zz of the system is 5 ~m ^2 .
  2. BThe magnitude of tension in the rod in subsequent motion is 2 mv ₀^2 9
  3. CThe ratio of moment of inertia about Z -axis at points A and B , I _ zz ^ A I _ zz ^ B =2
  4. DPoint C remains stationary during subsequent motion.

Correct answer

C. The ratio of moment of inertia about Z -axis at points A and B , I _ zz ^ A I _ zz ^ B =2

Step-by-step solution

For (B) : 2 mv ₀ =6 ~m ^2 = v ₀ 3 T =2 ~m ^2 = 2 mv ₀^2 9 For ( C ): I _ A =2 ~m (3 )^2 ; I _ B = m (3 )^2

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