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Finding speed of a object on slope

  1. Nov 11, 2013 #1
    1. The problem statement, all variables and given/known data

    A 42.5kg person is going down a hill sloped at 42.0 degrees.

    The coefficient of kinetic friction between the snow and skis is 0.180.

    How fast is the skier going 4.56 seconds after starting from rest?



    2. Relevant equations

    ffkmax=coefficient of kinetic friction*Normal Force

    fnet=mass*a

    mg*cos(42)

    mg*sin(42)


    3. The attempt at a solution

    mg=425

    mg*cos(42)=315.8

    Fn=mg*cos

    ffkmax=(.18)(315.8)=56.8

    ffkmax=netforce (no idea from this point on)

    fnet=ma 56.8/m=a 56.8N/42.5kg= 1.33ms/^2

    V=Vo+a*t

    V=(0)+(1.33)(4.56)=6.06m/s
     
  2. jcsd
  3. Nov 11, 2013 #2

    Andrew Mason

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    Science Advisor
    Homework Helper

    What are the forces acting on the skier? What are the directions of these forces?

    You seem to be saying that the friction force is the net force that is accelerating the skier down the hill!

    AM
     
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