Static friction on banked curve

[runner2392]

If a curve with a radius of 89.0m is perfectly banked for a car traveling 71.0km/hr, what is the minimum coefficient of static friction for a car not to skid when traveling at 91.8km/hr?

I figured out theta = 24. 03degs from the equations F(normal)*cos(theta) = mg and F(normal)*sin(theta) = m(v^2/r).

Then to find mus, I tried: m(v^2/r) = F(normal)sin(theta) -F(static f). For F(normal) I substituted mg/cos(theta) but ultimately I got the incorrect answer. Can someone please help?
Thanks

 

[ehild]

Make a drawing and show your work in detail, please. The static friction acts along the load: It contributes with its horizontal component to the centripetal force, and its vertical component has to be taken into account in the equation for the vertical force components.

ehild

 

[runner2392]

http://s1140.photobucket.com/albums/n575/sanjanz2392/?action=view&current=Untitled-2.jpg

 

[ehild]

How did you calculate with the friction?

ehild

 

[runner2392]

figured it out