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

Homework Help: Gravitational Energy Q

  1. Nov 11, 2008 #1
    1. The problem statement, all variables and given/known data

    How much energy is required to launch a 200 kg satellite from the surface of the earth into a circular orbit with radius 8.0 * 10^6 m?

    G=6.67*10^-11

    2. Relevant equations

    Ep= -GMm/r

    3. The attempt at a solution

    I calculated the gravitational potential energy of the object on the earth, then I calculated the gravitational potential energy of the object in the circualr orbit and then I subtracted the two and apparently thats not the correct way to tackle the problem.
     
  2. jcsd
  3. Nov 11, 2008 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi Effective! Welcome to PF! :smile:

    That will only give you enough energy to get it up there …

    you need it to stay up also! :biggrin:

    :wink: you gotta be practical!​
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook