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Homework Help: Speed of car on a curve bank?

  1. Oct 24, 2013 #1
    1. The problem statement, all variables and given/known data
    On a highway curve with radius 55m, the maximum force of static friction that can act on a 795kg car going around the curve is 8740N. What speed limit should be posted for the curve so that cars can negotiate is safely?

    2. Relevant equations
    ƩF=ma, a=v^2/r

    3. The attempt at a solution


    8740N= 4375m*kg(v^2)

    0.200m/s= v^2


    it looks like I performed my math correctly, but I need a second opinion. The solution that I solved does not appear in the answer choices of my practice exam.
  2. jcsd
  3. Oct 24, 2013 #2
    the answer choices are
    A) 241.23m/s
  4. Oct 25, 2013 #3


    User Avatar
    Gold Member

    It is D)

    m v2 / r = F

    v = √(98740.55/795) = 604.65408805031446540880503144654 :wink:
  5. Oct 26, 2013 #4
    thanks, but where did I go wrong with my math? everytime I isolate v I get letter E
  6. Oct 26, 2013 #5
    Thanks, but I believe the velocity that you gave did not work, :( 11.14 would be the velocity.

    Here's what I did, 8740N*55/795 = v^2

    v = 24.59m/s
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