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Homework Help: Finding distance with velocity, Uk

  1. Oct 23, 2007 #1
    1. The problem statement, all variables and given/known data
    An airplane makes a belly landing at 80km/h (I've converted to 22.22222m/s), the coefficient of kinetic friction between it and the runway is 0.60. How far does the airplane slide on the runway?

    2. Relevant equations
    acceleration = [sine(x) - (Uk)(cos(x))] x gravity (I used this formula for an incline question)
    V2[tex]^{}2[/tex] = V1[tex]^{}2[/tex] + 2ad

    3. The attempt at a solution

    I've tried using the acceleration = sinex ... formula to solve for the acceleration of the airplane, using an angle of 0 because this is the formula I used for an incline question. I found the acceleration was -5.88m/s/s, then plugged that in to the second formula, which yielded me a distance of 1.9m that the airplane travels...which doesn't really make sense to me:
    0 = 22.2 + 2(-5.88)(d)
    d = 1.9m
    Have I done something wrong, or is there an easier formula to use that I haven't come across in my class?
  2. jcsd
  3. Oct 23, 2007 #2
    You didn't square the initial velocity.
  4. Oct 23, 2007 #3
    oh my...thanks :blushing:
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