a curved section of a highway has a radius of curvature of R. the coefficent of friction between the standard automobile tires and the surface of the ighway is Us. What are all the forces on the car? What is the maxium speed the car of mass m can make it around the turn without skidding in terms of us.

Question

gebooors · Answer

Forces, which are acting, are weight, normal force and friction

gebooors · Answer

Friction is keeping the car in  a curvilinear motion.
Otherwise motion of the car would be straight forward,
Out from the curve.

gebooors · Answer

Then you have to solve velocity v from equation of motion
F = mv^2 / r

gebooors · Answer

F is a frictional force 
F = Us mg