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Homework Help: Did I do this question correctly?

  1. Nov 24, 2008 #1
    A race-car driver is driving her car at a record-breaking speed of 225 km/h. The first turn on the course is banked at 15°, and the car's mass is 1450kg.

    1. If the car maintains a circular track around the curve (does not move up or down the bank), what is the magnitude of the force of static friction?

    Do I use this formula?:

    F(s) = mv^2 / r

    And do I find the radius, using the formula V = √(g r tan15°)

    2. What is the coefficient of static friction necessary to ensure the safety of this turn?

    for this I use the formula µ(s) = F(s) / F(N) ?
  2. jcsd
  3. Nov 24, 2008 #2


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    Homework Helper

    Are you sure there is no radius given? Or that the curve was designed for a particular speed?

    The V2 = gRTanθ is based on the down-incline force of gravity being balanced by the up incline centripetal acceleration without friction. If you knew the speed it was designed for then you could use this formula.
    Last edited: Nov 24, 2008
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