For a car rounding a curve, the road should be banked at an angle according to the equation tan = v 2 /gr. Here,

For a car rounding a curve, the road should be banked at an angle θ according to the equation tanθ = v²/gr. Here, v is the speed of the car and r is the radius of the curve in the road. See Fig. 4.75. Find θ for v = 80.7 ft/s (55.0 mi/h), g = 32.2 ft/s², and r = 950 ft.

Fig. 4.75