Spinning Disk

A disk with a radial line painted on it is mounted
on an axle perpendicular to it and running through its center.
It is initially at rest, with the line at
q0 = -90°.
The disk then undergoes constant angular
acceleration. After accelerating for
3.1 s, the reference line has been
moved part way around the circle (in a counterclockwise direction) to
qf = 130°.
Given this information, what is the angular speed of the disk after it has traveled one complete revolution (when it
returns to its original position at -90°)?
|w| = rad/s
|