1. The problem statement, all variables and given/known data A civil engineer is asked to design a curved section of roadway that meets the following conditions: With ice on the road, when the coefficient of static friction between the road and rubber is 0.12, a car at rest must not slide into the ditch and a car traveling less than 70 km/h must not skid to the outside of the curve. What is the minimum radius of curvature of the curve? Answer in units of m 2. Relevant equations ∑F=mv^2/r 3. The attempt at a solution FnsinΘ+ FfcosΘ= mv^2 /r Then I went to the y direction to find Fn and got Fn=(mg+FfsinΘ/cosΘ) When I tried to get Ff out of the equation, I ended up subbing it for (μFnsinΘ/cosΘ) But then I still have Fn in the equation! This is really confusing me and the homework is due tonight so please help!