The Toyota Prius has a drag coeffi cient of 0.25, a frontal area of 23.4 ft2, and an empty weight of 3042 lbf. Its rolling resistance coeffi cient is Crr 5 0.03, that is, the rolling resistance is 3 percent of the normal force on the tires. If rolling freely down a slope of 88 at an altitude of 500 m, calculate its maximum velocity, in mi/h.