two disks are rotating about the same axis. disk a has a moment of inertia of $6\mathrm{.}48$ kg m$^2$ and an angular velocity of $4\mathrm{.}6$ rad$/$s$.$ disk b is rotating with an angular velocity of $-6\mathrm{.}71$ rad$/$s$.$ the two disks are then linked together without the aid of any external torques, so that they rotate as a single unit with an angular velocity of $-1\mathrm{.}27$ rad$/$s