A highway curve with radius 1000ft is to be banked so that a car traveling 56.0mph will not skid sideways even in the absence of friction

Question

At what angle should the curve be banked?

Answer 1

horizontal component of g = v^2/r
g sin theta = v^2/r

here g = 32 ft/s^2
v = 56 mi/h * 5280 ft/mi * 1 h/3600 s
r = 1000 ft