A playground merry-go-round of radius R = 2.00m has a moment of inertia I = 255kg·m2 and is rotating at 9.0rev/min about a frictionless vertical axle. Facing the axle, a 23.0kg child hops onto the merry-go-round and manages to sit down on its edge. What is the new angular speed of the merry-go-round?