A rotary dining table top lies in the xy plane and rotates about its central axis that is parallel to the z-axis.  At t = 0, the angular velocity of the top, ω_z = -5.00 rad/s. At t = 5.50 s, the angular velocity has increased steadily to +8.50 rad/s. Taking counterclockwise rotation as positive, determine the angular displacement of the disk at t = 5.50 s.