The differential gear of a car axle allows the wheel on the left side of a car to rotate at a different angular speed than the wheel on the right side. A car is driving at a constant speed around a circular track on level ground, completing each lap in 20.7 s. The distance between the tires on the left and right sides of the car is 1.59 m, and the radius of each wheel is 0.390 m. What is the difference between the angular speeds of the wheels on the left and right sides of the car?