(a) ok
(b) $a = 1.50 \, m/s^2$
you typed in 1.25, but arrived at the correct solution
(c) $\omega_f^2 = \omega_0^2 + 2\alpha \Delta \theta$
conversion of radians/sec to revolutions/min ...
$\dfrac{rad}{sec} \cdot \dfrac{1\, rev}{2\pi \, rad} \cdot \dfrac{60 \, sec}{1 \,min} = \dfrac{rev}{min}$
