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Homework Help: Physics 40S inclined Plane Problem. Please help!

  1. Mar 9, 2009 #1
    Boom-Boom Slapshot, Canadian hockey star, slides down a 50m long ice covered hill on his skates. The frictionless hill is inclined at 35° to the horizontal. Once he reaches the bottom of the hill, the ice is covered with deep snow that has a coefficient of kinetic friction of .50
    How far into the snow will BoomBoom go before coming to rest?



    Equations
    acceleration = fparallel / mass
    vf^2 = 2a Δd
    f = µFN
    FN = opposite of Fg which is mass x 9.8


    Attempt
    I drew out the problem and came to the conclusion that since I was working with an inclined plane that the mass of the hockey player didnt matter. I figured out (at least im pretty sure) that the acceleration is Sin35 * 9.8 = 5.62m/s
    Now I just dont know how to figure out the negative acceleration when he hits the snow. Because in order to calculate force friction, I need to know his mass. If someone could help me out it would be much appreaciated! Thank you
     
  2. jcsd
  3. Mar 10, 2009 #2

    tiny-tim

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    Welcome to PF!

    Hi Brodo17! Welcome to PF! :smile:
    Forget acceleration … the angle is only needed for calculating the height

    this is an energy problem …

    use conservation of energy on the hill,

    and the work-energy theorem ( work done = energy lost ) on the flat :wink:
     
  4. Mar 10, 2009 #3

    lanedance

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    Hi Brodo17

    tinytim is right on the money.... just thought I would add your acceleration looks correct & you could do it that way, but the looking at the energy will save you a heap of time & effort
     
  5. Mar 10, 2009 #4
    Thanks guys!
     
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