1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Can you assume that Jupiter has a circular orbit?

  1. Dec 30, 2003 #1
    When it is about the same distance from Jupiter, spacecraft on a mission to the outer planets has a speed that is 1.5 times the speed of Jupiter in its orbit. Why does the orbit of the spacecraft about the sun follow a hyperbolic orbit?

    Can you assume that Jupiter has a circular orbit? So far I've tried caltulating the total energies of the spacecraft and of Jupiter but I don't think that's correct.
     
  2. jcsd
  3. Dec 30, 2003 #2

    enigma

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Use the Vis-Viva equation

    [tex]

    V=\sqrt{\frac{2}{r}-\frac{1}{a}}

    [/tex]

    It's a safe assumption (unless they give it to you explicitly) that the eccentricity of planetary orbits are very small. That means that r~=a.

    What is the semimajor axis of a parabolic (or hyperbolic) orbit? You can solve for escape velocity with that.
     
  4. Dec 30, 2003 #3

    enigma

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I made a mistake.

    Vis Viva is:

    [tex]

    V=\sqrt{\mu*(\frac{2}{r}-\frac{1}{a})}

    [/tex]

    Where mu is the gravitational parameter, G*M or 398600.4 km^3/sec^2
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?