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Homework Help: Physics banking problems w\ friction.

  1. Oct 13, 2011 #1
    1. The problem statement, all variables and given/known data

    A 1200-kg car rounds a curve of radius 70m banked at an angle of 12 degrees. If the car is traveling at 90km/h, will friction force be required? If so, how much and in which direction?

    2. Relevant equations

    mv^2/r = Fc

    3. The attempt at a solution
    90km/h = 25m/s

    Fc = Fnx + uFny
    mv^2/r = mgsin12 + u9.8cos12

    25^2 = 9.8sin12 + u9.8cos12

    u=.72; The coefficient of friction .72 and the force of friction will be perpendicular to the normal force.

    Can someone confirm that this is the correct answer?
    Last edited: Oct 13, 2011
  2. jcsd
  3. Oct 13, 2011 #2

    Andrew Mason

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    Science Advisor
    Homework Helper

    You have a few errors in writing it out, but your answer is correct. You have not explained why friction is required.

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