Maxminum Velocity

Spectre32

This pertains to uniform circular motion, on a elvated curve, similar to a racetrack. Now, I know that the coffecient of static friction is mu_s=(v^2/gR)and that the max is equal to mu_s*N. Since the circle is curved and has an angle, i'm not sure how to apply what i have thus far into figure out the max velocity, before the car slides out.

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HallsofIvy

Homework Helper
I have absolutely no idea what you are talking about.

"Ok with Uniform circular motion if you want to figure out the maximun velocity that and object can sustain with going around before slideing off."

Slide off what? You don't even say WHAT is causing the object to move in a circle. I probably shouldn't mention the fact that this is not even a sentence.

"Now, I know that the coffecient of statci friction is mu_s=(v^2/gR)and that the max is equal to mu_s*N. "

If the object is already moving then static friction is irrelevant. Did you mean to say "kinetic friction" or "sliding friction"?

"Since the circle is curved and has an angle"

Maybe it would help if you said with respect to what the angle is measured.

Spectre32

ok, The circle is a racetrack, that is elvated up off the ground at an angle of Theta(at a curve). Now My goal is to figure out the maximun velocity that a car can obatin before sliding out of the cure. The only numbers that they give me are Radius= 200 and the coeff of static friction is mu_s between the tires and the pavement. As i had stated before I know hpw to figure out the max friction, it would be mu_s*N. I and just having a problem putting that and getting the velocity.

i was pondering the idea of this mu_s*R/cos(theta) it makes sense number wise when continuing on to the next step of the problem, when it tells you to give the velocity for angles 0-50 degrees and using a static friction of .60.

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HallsofIvy

Homework Helper
You know the radius of the track so you can calculate the force the track applies to the object to turn it (directed toward the center of the circle). The object itself applies the same force to the track, directed outward. Knowing that, and the angle at which the track is tilted, you can calculate the "normal" force- the component of that force that is directed straight into the track. That, multiplied by the coefficient of friction gives the frictional force applied by the track. If the component of force parallel to the track (the "other" component after you have taken off the normal force) is greater than that, the object will slide off the track.

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