Answer
(a) $17453.29rad/s^2$
(b) $38484.5rad$
Work Step by Step
(a) We can find the required angular acceleration as follows:
$\alpha=\frac{\omega-\omega_{\circ}}{t}$
We plug in the known values to obtain:
$\alpha=\frac{350000rpm-0rpm}{2.1s}$
$\alpha=17453.29rad/s^2$
(b) We can find the required number of revolutions as follows:
$\theta=\frac{\omega^2-\omega_{\circ}^2}{2\alpha}$
We plug in the known values to obtain:
$\theta=\frac{(350000rpm)^2-(0rpm)^2}{2(17453.29rad/s^2)}$
$\theta=\frac{(350000rpm(\frac{2\pi rad}{60s}))^2}{2(17453.29rad/s^2)}$
$\theta=38484.5rad$
