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Homework Help: Planet velocity

  1. Jul 15, 2008 #1
    1. The problem statement, all variables and given/known data

    At perihelion a planet in another solary system is 175 x 10 ^ 6km from its Sun and is traveling at 40km/s. At aphelion it 250 x 10 ^ 6 km distant and is traveling at?

    2. Relevant equations

    IiWi = IfWf
    3. The attempt at a solution

    What do i do?
  2. jcsd
  3. Jul 15, 2008 #2


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    Science Advisor
    Homework Helper

    Use conservation of angular momentum as you are trying to do. What are I and W in terms of mass m, velocity v and radius r of the planet?
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