$9\mathrm{.}9$ A bicycle wheel has an initial angular velocity of $150$ rad$/$s $($a$)$ If its angular acceleration is constant and equal to $0\mathrm{.}200$ rad$/$s$2,$ what is its angular velocity at t $=2\mathrm{.}50$s $($b$)$ Through what angle has the wheel turned between t $=0$ and t $=2\mathrm{.}50$ s$?$