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Concepts Of Physics MCQ Edition [Volume 1]
Exam
Concepts Of Physics MCQ Edition [Volume 1]
Subject
Physics
Chapter
Rotational Mechanics

Concepts Of Physics MCQ Edition [Volume 1] · Physics · Rotational Mechanics

Examine the two equations given below: (A) L = Iω (B) (dL)/(dt) =...

Examine the two equations given below:
(A) L=IωL = I\omega
(B) dLdt=Γ\dfrac{dL}{dt} = \Gamma
For a noninertial frame of reference,

Options

  1. AB is correct but A is incorrect
  2. Bboth A and B are incorrect
  3. Cboth A and B are correct
  4. DA is correct but B is incorrect

Correct answer

D. A is correct but B is incorrect

Step-by-step solution

The equation L=IωL = I\omega is a kinematic relation that defines the angular momentum of a rigid body. It depends on the mass distribution and the angular velocity relative to the frame of reference. This definition is valid in any frame, including non-inertial frames.

The equation dLdt=Γ\dfrac{dL}{dt} = \Gamma is the rotational analogue of Newton's second law, where Γ\Gamma is the net torque due to real forces. Newton's laws are valid only in inertial frames of reference. In a non-inertial frame, pseudo forces must be taken into account, which exert pseudo torques on the system. The correct equation in a non-inertial frame is dLdt=Γreal+Γpseudo\dfrac{dL}{dt} = \Gamma_{\text{real}} + \Gamma_{\text{pseudo}}.

Therefore, A is correct but B is incorrect.
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