# Need Help- Centripetal car problems, finding the angle

1. Oct 13, 2012

### Lolagoeslala

1. The problem statement, all variables and given/known data

Find the angle at which a curve of radius 100m, should be
banked in order that a car moving at a speed 90 km/h will not
need any frictional force to round it

3. The attempt at a solution
Alright so what i did was, i made two equations....
Fc=Fnsinθ
ma=mgsinθ
v^2/r=gsinθ this is the horizontal force toward the centre of the circle.

And now for the verticle equilibrium
Fg= Fncosθ is this correct i am not understanding how i would do this?

AND THE REST i am really confused about what to do...

Last edited: Oct 13, 2012
2. Oct 13, 2012

### frogjg2003

Try writing the equations for parallel and perpendicular to the road.
Just keep in mind that you aren't dealing with an inertial reference frame. The $F_c$ pointing in that is your centripetal force, is the same as a centrifugal force pointing out in this reference frame.

3. Oct 14, 2012

### Tupac

Who r u Lola. You go to my school cause all of your questions you're asking are from an assignment. Message me back, cause i wanna compare answers with u.