A flat (unbanked) curve on a highway has a radius of 215.0 m . A car rounds the curve at a speed of 25.0 m/s .What is the minimum coefficient of static friction that will prevent sliding?Suppose that the highway is icy and the coefficient of friction between the tires and pavement is only one-third what you found in the previous part. What should be the maximum speed of the car so it can round the curve safely?