Conservation of Angular Momentum (Problem 54)

A cylinder with rotational inertia $I_1=2.0\text{kg}\cdot {\text{m}}^2$ rotates clockwise about a vertical axis through its center with angular speed ${\omega }_1=5.0\text{rad}\text{/}\text{s}.$ A second cylinder with rotational inertia $I_2=1.0\text{kg}\cdot {\text{m}}^2$ rotates counterclockwise about the same axis with angular speed ${\omega }_2=8.0\text{rad}\text{/}\text{s}$. If the cylinders couple so they have the same rotational axis what is the angular speed of the combination? What percentage of the original kinetic energy is lost to friction?