Two coaxial discs

PHYSICS · Single correct · CBSE · Physics · System of Particles and Rotational Motion · System of Particles and Rotational Motion

Problem

Two coaxial discs, having moments of inertia

I_1

and

\frac{I_1}{2}

, are rotating with respective angular velocities

\omega_1

and

\frac{\omega_1}{2}

, about their common axis. They are brought in contact with each other and thereafter they rotate with a common angular velocity. If

E_f

and

E_i

are the final and initial total energies, then

(E_f - E_i)

is: (1)

-\frac{I_1 \omega_1^2}{12}

(2)

\frac{I_1 \omega_1^2}{6}

(3)

\frac{3}{8} I_1 \omega_1^2

(4)

-\frac{I_1 \omega_1^2}{24}