Quote:
Originally Posted by phantomcow2
This was a test question today. What pisses me off is that I have solved a problem almost exactly like this before, a few months ago. I can't remember at all how I did it
"A car is driving in a circuit with a radius of 35m, what is the max velocity it could be traveling at? Coefficient friction is .453".
Any ideas? Something to jump start my mind?

If the track surface is level (rather than banked), then the normal force on the car is equal to its weight mg (where m=car's mass, g = gravitational field). Maximum force of friction is the coefficient of friction times the normal force.
Meanwhile, the force needed for the car to navigate the circle is its mass m times the centripetal acceleration v^2/ r.
The car is driving at the maximum possible speed when the needed force ( mv^2/ r) equals the maximum possible force ( mg times the coefficient of friction).
So set these two expressions equal, notice that the car's mass m cancels out (which is good, since they didn't give it to you), and solve for v.
