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Homework Help: Car going around banked curve with no friction

  1. Feb 13, 2012 #1
    1. The problem statement, all variables and given/known data
    a racecourse is designed with curves with a radius of 200m and a 10degree banking. What is the maximum speed a car can negotiate the curve without friction?


    2. Relevant equations
    newtons 3 laws


    3. The attempt at a solution
    tanTheta = v^2/gR
    tan10 = v^2/(9.8 * 200m)
    v = 345 m/s^2

    is this right?
     
  2. jcsd
  3. Feb 13, 2012 #2

    tiny-tim

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    hi chaotiiic! :smile:
    formula looks ok

    are you sure about the 345 ?

    (and speed is m/s, not m/s2)
     
  4. Feb 13, 2012 #3
    so is it 0.1763 = v^2/1960
    v^2=345.6
    v=18.59m/s
     
  5. Feb 13, 2012 #4

    tiny-tim

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    yes! :smile:

    (are you ok now, or is there anything you're still not sure about?)​
     
  6. Feb 13, 2012 #5
    thankyou. :surprised
    im actually still confused about everything. the only reason i was able to answer this problem is because there's a problem identical in my book to the one i asked. my teacher gives out quizzes before lectures so hopefully ill understand when i go to class later today.
     
  7. Feb 13, 2012 #6

    tiny-tim

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    ok, so you don't understand the reason for the formula? …
    like almost all dynamics questions, it all boils down to good ol' Newton's second law (F = ma) …

    you know the acceleration (as a function of v),

    and although you know the weight, you don't know the normal force …

    so you do F = ma perpendicular to the unknown (normal) force :smile:
     
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