Answer
28.12 m
Work Step by Step
For an unbanked curve, the static friction coefficient for rubber on wet concrete is 0.7. The static frictional force will be at its maximum if the car is just at the point of slipping. We find the radius of curvature using the following formula:
$$\frac{mv^2}{r}=µ_s mg$$
Rearranging the above formula and solving:
$$r=\frac{v^2}{µ_sg}=\frac{((50km/h)(\frac{1000m}{1km})(\frac{1h}{3600s}))^2}{(0.7)(9.8m/s^2)}=28.12m$$
So, the radius of the curvature of the unbanked curve is 28.12 m.