Answer
(a) $\alpha=6.29\ \frac{rev}{s^2}$
(b) $327\ rev$
Work Step by Step
(a) We know that
$\alpha=\frac{\omega-\omega_{\circ}}{t}$
We plug in the known values to obtain:
$\alpha=\frac{(0)-(3850\frac{rev}{min}\times 1\frac{1min}{60s})}{0.2}=6.29\ \frac{rev}{s^2}$
(b) As $\Delta \theta=\frac{1}{2}(\omega+\omega_{\circ})$
We plug in the known values to obtain:
$\Delta \theta=\frac{1}{2}(0+3850\frac{rev}{min}\times 1\frac{min}{60s})(10.2s)=327\ rev$