The discs of moments of inertia `I_1` and `I_2` about their respective axis (normal to the disc and passing through the centre), and rotating with agnular speeds `omega_1` and `omega_2` are brought into contact face to face with their axis of rotation coincident.
Show that the kinetic energy of the combined system is less than the sum of the initial kinetic energies of the two discs. How do you account for this loss in energy ? Take `omega_1 ne omega_2`.