a. The wheel accelerates uniformly, so its constant acceleration is equal to the average acceleration:
[tex]\alpha=\dfrac{0.20\frac{\rm rev}{\rm s}-0}{32.0\,\rm s}=0.0063\dfrac{\rm rev}{\mathrm s^2}[/tex]
b. Yes. Since
[tex]\alpha=\dfrac{\Delta\omega}{\Delta t}=\dfrac\omega{\Delta t}[/tex]
then multiplying [tex]\alpha[/tex] by 2 means we double the change in angular speed, but the wheel starts from rest so only the final angular speed [tex]\omega[/tex] gets doubled.