1. The problem statement, all variables and given/known data If a curve with a radius of 88m is perfectly banked for a car traveling at 75km/h, what must be the coefficient of static friction for a car not to skid when traveling at 95 km/hr 75km/h = 20.8m/s 95km/h = 26.4m/s 2. Relevant equations Fr=mv^2/r Fr=centripetal force m = mass r = radius v = velocity Fn= normal force Ffr= force of friction (Us*Fn) g = gravitational acceleration Us = coefficient of static friction 3. The attempt at a solution Horizontal component sinθFn=mv^2/r Eq 1 Vertical component cosθFn=mg Fn=mg/cosθ Eq 2 Sub eq 2 into 1 sinθ (mg/cosθ) = mv^2/r (sinθ/cosθ = tanθ) tanθ mg = mv^2/r m cancels out tanθ = v^2/gr θ = arctan 20.8^2/9.8*88 θ = 26.6 degrees Am I right up to there? Now for the second part of the question. Solving for Us. See diagram for force of friction and horizontal and vertical components Vertical component cosθFn - sinθFfr - mg = 0 ( there is no vertical displacement) Solve for Fn Fn= (sinθFfr + mg)/cosθ Horizontal component sinθFn + cosθFfr = mv^2/r Sub Fn from above sinθ ((sinθFfr + mg)/cosθ) + cosθFfr = mv^2/r From here I am unable to isolate Ffr, or cancel out the mass.... Help!!