A 47 kg monkey is standing at the center of a disk that is rotating horizontally at an angular velocity of 0.72 rad/s. The moment of inertia of the disk is 840 kg.m² and its radius is 2.0 m. The monkey walks straight to the edge of the disk while the disk rotates without any external forces being applied to it. Given that there is no friction, determine the disk's angular velocity after the monkey reaches the edge.