Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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


    User Avatar
    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
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook