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Homework Help: Angular momentum

  1. Nov 21, 2006 #1
    A 2kg object has a position vector r = -4t i + 3t^2 j (m). Find its angular momentum relative to the origin as a function of time.

    The correct answer is -24t^2 k (kgm^2/s).

    I know that L = r*p and p is mv

    so I differentiate r to get v

    v = -4 i + 6t j

    do I just multiply 2 and the cross proudct of r and v? I don't know what to do because of the t in the equation for vector r.
  2. jcsd
  3. Nov 21, 2006 #2


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    Science Advisor
    Homework Helper

    Just do it. The angular momentum is to be found as a function of time. t will be in the result
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