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Homework Help: Nonconservative Force Question- !

  1. Sep 23, 2007 #1
    Nonconservative Force Question--URGENT!

    A skier traveling 12 m/s reaches the foot of a steady upward 18 degree incline and glides 12.2 meters up along this slope before coming to rest. What was the average coefficient of friction?

    Work nonconservative= mechanicalenergyfinal-mechanicalenergyinitial

    Wnc= (1/2mvf^2+mghf)- (1/2mvi^2-mghi)

    i used Ff= force of friction, and 3.7 coming from sin 18= (x/12.2)- 3.7 is the height of the incline plane.
    m= mass

    Ff*12.2= (9.8)(3.7)m-(1/2(12.0^2))m

    and got Ff(12.2)= 35.74 m

    so Ff= 2.92m, which means the coefficient of friction, u= 2.92m/9.8mcos18, the masses then cancelling out.

    my question is, do you have to take the x-component of weight into account at all? does it affect the force of friction and thus the coefficient of friction? or do you just ignore the x-compent of weight, mgsin18?

    any help would be very much appreciated, i've been debating this all weekend- thank you in advance!
    Last edited: Sep 23, 2007
  2. jcsd
  3. Sep 23, 2007 #2


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    Homework Helper

    Looks to me like everything is correct.
  4. Sep 23, 2007 #3
    thank you very much, learningphysics! you have no idea how much better that makes me feel- i have a test tomorrow in ap physics! :-) thats what i thought, i just wasn't sure and i KNOW there'll be a problem like that on the test..
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