Question

A horizontal disk is rotating counter-clockwise about its axis of symmetry at 14 rps. Its
rotational inertia with respect to its axis of symmetry is 8 kg m2
. A second disk, of
rotational inertia 2 kg m2
with respect to its axis of symmetry, rotating clockwise about
the same axis at 7 rps, is dropped on top of the first disk. The two disks stick together
and rotate as one about their common axis of symmetry. What is the angular velocity of
the system?