A round disc of moment of inertia $I_{2}$ about its axis perpendicular to its plane and passing thro

Question

A round disc of moment of inertia $I_{2}$ about its axis perpendicular to its plane and passing through its centre is placed over another disc of moment of inertia $I_{1}$ rotating with an angular velocity $\omega$ about the same axis. The final angular velocity of the combination of discs is\

Professor PC Thomas Classes · Answer

(c) : Applying conservation of angular momentum $$ I_{1} \omega=\left(I_{1}+I_{2}ight) \omega_{1} 	ext { or } \omega_{1}=\frac{I_{1}}{\left(I_{1}+I_{2}ight)} \omega $$