Let the car's mass be m and its weight be (m)(g). Write the formula for the centripetal force needed to keep the car moving in a circle of radius 30.5 meters when the car has velocity v. (I assume you know the formula for centripetal (or centrifugal) force.) Set this equal to the maximum frictional force the tires can exert, which is (m)(g)(0.60) Solve for v.
