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Homework Help: Parametric Particle

  1. May 18, 2007 #1
    1. The problem statement, all variables and given/known data
    Consider a particle along a curve C and whose position is given by the vector:
    s(t) = < sqrt(t2), t3 - 3t >

    Last part of the question:
    There is an unknown force that is keeping this particle on trajectory C. At what value of t must the force cease in order for the particle to pass through the point (3,1)?
    When will it arrive at this point and with what speed?

    3. The attempt at a solution
    Ive tried setting the slope of (3,1) and the point (xt, yt) to equal dy/dx. But I keep getting a value of t that places the point (3,1) on the tangent line behind the particles path. The particle reaches (3,1) at a time before it even gets to (xt, yt) on the curve.

    t3-3t-3 / abs(t)-1 = (3t2 -3)t/abs(t)

    Is there anything wrong with the setup? Why do I keep getting an extraneous solution when letting t be >0 and when letting t be <0?
  2. jcsd
  3. May 20, 2007 #2
    Nevermind, I got it. This thread can be deleted
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