A flat uniform circular disk (radius = 2.10 m, mass = 100 kg) 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 45.0 kg person, standing 1.3 m from the axis, begins to run on the disk in a circular path and has a tangential speed of 2.80 m/s relative to the ground.
Find the resulting angular speed of the disk (in rad/s)