A horizontal disc rotates freely about a vertical axis through it centre. A ring, having the same mass and radius as the disc, is now gently placed on the disc. After some time, the two rotate with a common angular velocity. Select the correct statements from the following.

Let ω1 = the initial angular velocity of the disc. ω2 = the final common angular velocity of the disc and the ring. For the disc, I1=12mr2For the ring, l2=mr2By conservation of angular momentum, L=I1ω1−I1+I2ω2 or  ω2=l1ω1I1+I2=ω1/3 Initial kinetic energy =E1=12I1ω12 Final kinetic energy =E2=12I1+I2ω22 Heat produced = loss in kinetic energy =E1−E2 Ratio of heat produced to initial kinetic energy =E1−E2E1=23