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!

Basic Orbit Satalite Questions Please help!

  1. Nov 26, 2007 #1
    1. The problem statement, all variables and given/known data

    The polar-orbiting environmental satellites (POES) and some military satallites orbit at a much lower level in order to obtain more detailed information. POES complete an earth orbit 14.1 times per day. What are the orbital speed and the altitude of POES?

    T = 1.7 h
    G = 6.67x10^-11
    M earth = 5.98x10 ^24

    2. Relevant equations

    The international space station orbits at an altitude of approximately 226km. What is its orbital speed and period?

    3. The attempt at a solution

    What i tried to do was,

    R^3 = (G)(M Earth)
    T^2 _____4π^2
     
  2. jcsd
  3. Nov 26, 2007 #2
    Somebody please help me ! :(
     
  4. Nov 26, 2007 #3

    D H

    User Avatar
    Staff Emeritus
    Science Advisor

    You have units for the orbital period, why not for G and the mass of the Earth? Those things have units too, and unless you apply them consistently you will get the wrong answer. You used the values [itex]G=6.67*10^{-11}\mathrm{m}^3/\mathrm{kg}/\mathrm{s}^2[/itex] and [itex]M_{\oplus}=5.98*10^{24} \mathrm{kg}[/itex] in conjunction with time in hours and distance in kilometers.
     
  5. Nov 26, 2007 #4
    Thank's.

    So how do i do the question?
     
  6. Nov 26, 2007 #5

    D H

    User Avatar
    Staff Emeritus
    Science Advisor

    Make sure you use consistent units throughout. That value of G is in m3/kg/s2. If you want to use that particular value, you had better represent lengths in meters, not kilometers, and time in seconds, not hours.
     
  7. Nov 26, 2007 #6
    Ooo.. Thanks man :)

    But how do i use the equasion when they only give that much information, i am lost :( But i do understand your point.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Basic Orbit Satalite Questions Please help!
Loading...