A disk rotates at constant angular acceleration, from angular position theta$1=16\mathrm{.}0$ rad to angular position theta$2=80\mathrm{.}0$ rad in $5\mathrm{.}60$ s$.$ Its angular velocity at theta$2$ is $16\mathrm{.}0$ rad$/$s$.($a$)$ What was its angular velocity at theta$1?($b$)$ What is the angular acceleration? $($c$)$ At what angular position was the disk initially at rest?