$[$Q$7]$ A $3\mathrm{.}45-kg$ centrifuge takes $100$ s to spin up from rest to its final angular speed with constant angular acceleration. A point located $8\mathrm{.}00$ cm from the axis of rotation of the centrifuge moves with a speed of $150\frac{m}{s}$ when the centrifuge is at full speed. What is the angular acceleration $($in $ra\frac{d}{s^2})$ of the centrifuge as it spins up$?$

a$.,18\mathrm{.}75ra\frac{d}{s^2}$

b$.9\mathrm{.}375ra\frac{d}{s^2}$

c$.,1\mathrm{.}875ra\frac{d}{s^2}$

d$.1\mathrm{.}5ra\frac{d}{s^2}$

e$.0\mathrm{.}1875ra\frac{d}{s^2}$