What is the radius of curvature of a convex bridge, moving along which at a speed of 72 km / h

What is the radius of curvature of a convex bridge, moving along which at a speed of 72 km / h, the car would not put pressure on the bridge?

These tasks: V (vehicle speed) = 72 km / h (in the SI system V = 20 m / s); P (pressure generated by the vehicle on the axle) = 0 N.
Reference values: g (acceleration due to gravity) ≈ 10 m / s2.
The radius of curvature of a convex bridge can be expressed from the formula: P = 0 = m * (g – an) = m * (g – V ^ 2 / R), whence g = V ^ 2 / R and R = V ^ 2 / g.
Let’s do the calculation: R = 20 ^ 2/10 = 40 m.
Answer: The radius of curvature of the convex bridge should be 40 meters.