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JEE Main2012PhysicsRotational MotionActual

This question has Statement 1 and Statement 2. Of the four choices given after the Statements, choose the one that best describes the two Statements. Statement 1: When moment of inertia I of a body rotating about an axis with angular speed increases, its angular momentum L is unchanged but the kinetic energy K increases if there is no torque applied on it. Statement 2: L=I , kinetic energy of rotation = 1 2 I ^2

Options

  1. AStatement 1 is true, Statement 2 is true, Statement 2 is not the correct explanation of Statement 1.
  2. BStatement 1 is false, Statement 2 is true.
  3. CStatement 1 is true, Statement 2 is true, Statement 2 is correct explanation of the Statement 1.
  4. DStatement 1 is true, Statement 2 is false.

Correct answer

B. Statement 1 is false, Statement 2 is true.

Step-by-step solution

As L=I so L increases with increase in . Kinetic energy _ (rotational) depends on an angular velocity ' ' and moment of inertia of the body I . i.e., K E ( . rotational = 1 2 I ^2

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