Two coaxial discs, having moments of inertie `I_1` and `I_1/2` are rotating with respective angular volecities `omega_1` and `(omega1)/2`, about their common axis.They are brought in contact with each other and thereafter they rotate with a common angular volecity.If `E_f` and `E_i` are the final and initial total energies, then `(E_f-E_1)` is:
