Answer:
0.063
Step-by-step explanation:
velocity of the car, v = 40 km/h = 11.11 m/s
radius, r = 200 m
Let the coefficient of friction is μ.
The coefficient of friction relates to the velocity on banked road is given by

where, v is the velocity, r be the radius of the curve road and μ is coefficient of friction.
By substituting the values, we get

μ = 0.063