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Homework Help: Very basic physics problem

  1. Apr 10, 2009 #1
    1. The problem statement, all variables and given/known data
    A particle is moving along a straight line such that its acceleration is defined as a = (-2v) m/s^2, where v is in meters per second. If v = 20 m/s when s = 0 and t = 0, determine the particle's velocity as a function of position, and the distance the particle moves before it stops.

    2. Relevant equations
    Basic kinematics equations

    3. The attempt at a solution
    I tried using dt = dv/a and integrating that, and I got t = (ln20 - lnv)/2, then I tried substituting it into s = s0 + v0t + (1/2)at^2, and now I'm stuck. Any help would be appreciated. Thanks :)
  2. jcsd
  3. Apr 10, 2009 #2


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    Homework Helper

    Use the fact that

    [tex]a= \frac{dv}{dt}=v \frac{dv}{ds}[/tex]

    this will help you get velocity in terms of displacement.
  4. Apr 10, 2009 #3
    Oh right. Thanks a bunch :)
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