A) I-70 is building a new curved exit. It will be banked so that cars can exit the highway at 45 mph (20.1 m/s). The radius allotted for this curve is 65 m. At what angle should the curve be banked if there is no friction? b) If the coefficient of friction between the tires and the road is 1.2, how fast can a car take the curve?

An explanation would be helpful:)