I'm given this problem: A roadway is being designed for automobiles traveling 50 mph. If θ = 20 ∘ , g = 32.2, and f = 0.38, calculate R to the nearest foot.
I'm trying to understand the relation between every variable, my current understanding is: R = the raidius of the circle the bank is creating as the car goes around and is also what i'm solving for in this equation, V^2 is the volicity so it'll be MPH converted squared, g I think if the force of gravity pushing down on the car? f i think is the static friction? but that doesn't make sense to me. Lasty tan theta is obvious the angle of the bank.
when I insert it all I believe it'll end up like this, if i did anything wrong please let me know, i really want to understand the relation though.
(73.33)^2
R = -----------------------
32.2((.38+tan(20))
+36916 BTW " ....the coefficient of static friction is equal to the tangent of the angle at which the objects slide..." 
