A flat uniform circular disk (radius = 4.91 meter, mass = 400 kilogram) is initially stationary. The disk is free to rotate in the horizontal plane about a frictionless axis perpendicular to the center of the disk. A 56.0 kilogram man, standing 1.21 meter from the axis, begins to run on the disk in a circular path and has a tangential speed of 2.20 m/s relative to the ground. Obtain the resulting angular speed of the disk.
(in rad/s)