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## Homework Statement

A curve with a 200-m radius on a level road is banked at the correct angle for a speed of 60 km/h, i.e. a car traveling at this speed would remain on the road, even if the surface were frictionless.

a) If a car travels around this curve at a speed of 90 km/h, what is the minimum coefficient of static friction between the tires and the road that will prevent skidding?

b) If the surface were wet, would the speeding car in part (a) remain on the road?

c) If it was raining, and the car had to slow down to a crawl (for example, to safely pass a stranded vehicle), would it slide down the inclined roadway?

## Homework Equations

Friction = force applied/(mass*gravity)

F=ma

## The Attempt at a Solution

I made a post earlier about another problem... I'm staring at these problems... and I have no idea how to solve them. I took notes on things relevant to these, but I have no idea how to apply them. In parentheses, mindless ranting [It might seem like I'm out just trying to get the easy answer to these.. but I really just need some kind of hint or something. I have no idea how to apply the relevant equations to the problem. Once again i would appreciate some kind of explanation as to how these kinds of problems work, so I can attempt to solve these kinds of problems. I'm better at math than physics, because I really am bad at application of equations.] Mainly, I don't understand how you can drive along a curve without any friction. I could understand that if there were something on the sides guiding you on the curve, but I think you would drift out of the curve if there were no friction.