On a wet racetrack, the maximum safe speed, to avoid sliding on a level circular curve with a radius of curvature of 56 m, is 73 km/hr. What is the coefficient of friction between the car's tires and the track surface?

Answer 1

First convert 73 km/hr to
Vmax = 20.28 m/s

Then solve
M*g*u = M*V^2/R
or, since the M cancels out,
u = Vmax^2/(R*g)

u is the coefficient of friction that you want.