The flywheel turns clockwise with a constant speed of 580 rev/min, and the connecting rod AB slides through the pivoted collar at C. For the position θ = 48°, determine the angular velocity ωAB (positive if counterclockwise, negative if clockwise) of AB by using the relative-velocity relations. (Suggestion: Choose a point D on AB coincident with C as a reference point whose direction of velocity is known.)