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Homework Help: Displacement HW Question-STUMPED!

  1. Jun 13, 2007 #1
    1. The problem statement, all variables and given/known data

    A skateboarder, starting from rest, rolls down a 15.0 m ramp. When she arrives at the bottom of the ramp her speed is 7.95 m/s.

    (a) Determine the magnitude of her acceleration, assumed to be constant.

    (b) If the ramp is inclined at 23.0° with respect to the ground, what is the component of her acceleration that is parallel to the ground?

    2. Relevant equations

    v squared=v initial squared +2ax
    kinematics equations..

    3. The attempt at a solution

    I tried so many times to get the answer! I tried making a right triangle with 23 degree angle and cos 23=x/2.1, it didnt work out...i'm so confused, please help!
     
  2. jcsd
  3. Jun 13, 2007 #2

    Doc Al

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    Staff: Mentor

    Seems OK to me. How do you know it's wrong? Did you use enough significant figures?
     
  4. Jun 13, 2007 #3
    I don't know, that's probably it though! I'm using webassign and it tells u if its wrong or not
     
  5. Jun 13, 2007 #4

    Doc Al

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    Staff: Mentor

    What did you enter exactly?
     
  6. Jun 13, 2007 #5
    Yeah, that's it. Haha, dumb Webassign! That was the first answer I put in too.
    Thanks so much =)
     
  7. Jun 14, 2007 #6
    Beginning the way DocAl begins it is fairly a easy question.
    I can help you in the first part,
    use the equation v^2=u^2+2as
    all the data is given in the quation and after getting this part i would prefer that you think about it.
     
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