IF the Road is not banked then, we have no bending of car towards the vertical.
The friction force between the tyres and ground supplies the centripetal force needed to negotiate the curve.
m v² / r = Mu N = Mu m g Mu = coefficient of friction
g = acceleration due to gravity m = mass of car, N normal reaction from ground
so v = √ ( Mu r g ) = √ 0.40 * 410 * 9.8 = 40.09 m/sec
This is the maximum speed which is safe. If it is exceeded, friction can not supply centripetal force. So tyres will skid and car will go away from the curve.
v = 144 km ph
