$10\mathrm{.}2$ Rotation with Constant Angular Acceleration

A wheel rotates with a constant angular acceleration of $6\mathrm{.}0ra\frac{d}{s^2}.$ During a certain time interval, its angular displacement is $6\mathrm{.}0$ rad $.$ At the end of the interval, its angular velocity is $12\mathrm{.}0ra\frac{d}{s}.$ Its angular velocity at the beginning of the interval is

$6\mathrm{.}0ra\frac{d}{s}$

$0ra\frac{d}{s}$

$8\mathrm{.}5ra\frac{d}{s}$

$1\mathrm{.}0ra\frac{d}{s}$

$12ra\frac{d}{s}$