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Homework Help: Kinematics, given only vi vf and d

  1. Oct 4, 2008 #1
    Kinematics, given only "vi" "vf" and "d"

    1. The problem statement, all variables and given/known data

    I have a hunch this problem is impossible with the given information.

    Using the given information, solve for a and t.

    vi = 7.185m/s
    vf = -7.185m/s
    a = ?
    d = 0m
    t = ?

    2. Relevant equations

    Not sure, I think this would be correct.

    vf^2 = vi^2 + 2ad (The problem here is obvious when d = 0)
    d = 1/2(vi+vf)t (Once again, as far as I can tell, useless when d = 0)

    3. The attempt at a solution

    Well I can plug and chug the numbers the same as anyone, the problem is that it will always come out to zero.

    Thanks in advance guys.
     
    Last edited: Oct 4, 2008
  2. jcsd
  3. Oct 4, 2008 #2

    gabbagabbahey

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    Re: Kinematics, given only "vi" "vf" and "d"

    Are you sure d=0? What is the original problem statement, word for word?
     
  4. Oct 4, 2008 #3
    Re: Kinematics, given only "vi" "vf" and "d"

    d certainly is 0.
    The question is exactly as I have above.
    My impression was that this question resembled the vertical component of a projectile motion question. Up and back down, 0 displacement.
     
  5. Oct 4, 2008 #4
    Re: Kinematics, given only "vi" "vf" and "d"

    My opinion is that it can't be solved with only that information. Perhaps we're thinking too hard though
     
  6. Oct 4, 2008 #5
    Re: Kinematics, given only "vi" "vf" and "d"

    It would seem to me that the question has been misinterpreted, or miswritten. I certainly don't see a way to solve it with the current data.
     
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