A circular curve of highway is designed for traffic moving at 97 km/h. Assume the traffic consists of cars without negative lift. (a) If the radius of the curve is 140 m, what is the correct angle of banking of the road? (b) If the curve were not banked, what would be the minimum coefficient of friction between tires and road that would keep traffic from skidding out of the turn when traveling at 97 km/h?