On a curved roadway of radius 100m, the suggested speed is 35mph(approximately 16m/s). What must the coefficient of friction be between a car's tires and the road for the car to safely negotiate the curve at the posted speed?

Answer 1

is the roadway flat?

if so,

mv^2/r-mg*coeff=0
solve for coeff

Answer 2

A roadway is designed for traffic moving at a speed of 68 m/s. A curved section of the roadway is a circular arc of 140 m radius. The roadway is banked--so that a vehicle can go around the curve--with the lateral friction forces equal to zero. The angle at which the roadway is banked is closest to:
Select one:
a. 73°
b. 67°
c. 75°
d. 69°
e. 71°