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Homework Help: Velocity vectors

  1. May 4, 2009 #1
    1. The problem statement, all variables and given/known data

    A particle moves with position function r(t) = t lnt[tex]\hat{i}[/tex] + t[tex]\hat{j}[/tex] + e-t[tex]\hat{k}[/tex]
    Find the velocity vector, speed, and acceleration.

    2. Relevant equations

    3. The attempt at a solution

    [tex]\hat{v}[/tex](t) = (1 + lnt)[tex]\hat{i}[/tex] + [tex]\hat{j}[/tex] - e-t[tex]\hat{k}[/tex]
    [tex]\hat{a}[/tex](t) = 1/t [tex]\hat{}i[/tex] + e-t [tex]\hat{k}[/tex]
    [tex]\left\|[/tex]v(t)[tex]\right\|[/tex] = [tex]\sqrt{lnt + e^(-2t) + 2lnt + 2}[/tex]
    Last edited: May 4, 2009
  2. jcsd
  3. May 5, 2009 #2


    Staff: Mentor

    v(t) and a(t) look good, but you're a little off on ||v(t)||. The ln t term under the radical should be (ln t)2. Maybe you just forgot to put it in while writing the LaTeX code.
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