ExamBro
ExamBro
NEET · Physics · STD 11 - 6. system of particles and rotational motion

Two discs of same moment of inertia rotating about their regular axis passing through centre and perpendicular to the plane of disc with angular velocities \(\omega_1\) and \(\omega_2\) They are brought into contact face to face coinciding the axis of rotation. The expression for loss of energy during this process is 

  1. A \(I{\left( {{\omega _1} - {\omega _2}} \right)^2}\)
  2. B \(\frac{I}{8}{\left( {{\omega _1} - {\omega _2}} \right)^2}\)
  3. C \(\;\frac{I}{2}{\left( {{\omega _1} + {\omega _2}} \right)^2}\)
  4. D \(\;\frac{I}{4}{\left( {{\omega _1} - {\omega _2}} \right)^2}\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(\;\frac{I}{4}{\left( {{\omega _1} - {\omega _2}} \right)^2}\)

Step-by-step Solution

Detailed explanation

Initial angular momentum = \(I{\omega _1} + I{\omega _2} \) Let \(\omega \) be angular speed of the combined system.