The magnitude of static friction is
f = mv ²/r
(i.e. the net force acting on the car parallel to the road points toward the center of the curve)
while the net vertical force must be
∑ F = n - mg = 0
because the car is otherwise in equilibrium. Then
==> n = mg
==> f = µn = µmg = mv ²/r
==> µ = v ²/(rg)
We have
v = 101 km/h ≈ 28.1 m/s
r = 110 m
g = 9.80 m/s²
so that
µ = (28.1 m/s)² / ((110 m) g) ≈ 0.730
