A 200 g toy car is placed on a narrow 66-cm-diameter track with wheel grooves that keep the car going in a circle. The 1.5 kg track is free to turn on a frictionless, vertical axis. The spokes have negligible mass. After the car's switch is turned on, it soon reaches a steady speed of 0.70 m/s relative to the track.
What is the tracks's angular velocity, in rpm?