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Homework Help: Skier down a slope problem

  1. Oct 26, 2009 #1
    1. The problem statement, all variables and given/known data
    You, a 75-kg skier, glide straight down a snow-covered slope inclined at 15 degrees to the horizontal over spring break. Let's be realistic, what is your acceleration(magnitude and direction) Assume your skis are wood and the snow is dry. mu_k on snow is 0.060.

    2. Relevant equations

    3. The attempt at a solution
    Fx = -fk+mgsin[tex]\theta[/tex] = ma
    Fy = n = mgcos[tex]\theta[/tex]

    -mu_k*mgcos[tex]\theta[/tex] = ma - mgsin[tex]\theta[/tex]
    a = -mu_k*g*cos[tex]\theta[/tex] + gsin[tex]\theta[/tex]
    a = (.060)(9.8)cos15 + 9.8sin15
    a = 8.22 m/s2

    Did I do the first part right? And, how would I find the direction?
  2. jcsd
  3. Oct 26, 2009 #2


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    Homework Helper

    Looks like you dropped a minus sign in that step.
    The friction force opposes the parallel component of gravity, so there ought to be subtraction rather than addition.
  4. Oct 26, 2009 #3
    Wow, I did that by mistake and didn't even catch it. Thanks, so would 1.97m/s2 be correct?
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