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!

Gravitation/Average Force Problem

  1. Nov 26, 2007 #1
    1. The problem statement, all variables and given/known data
    What are (a) the speed and (b) the period of a 220 kg satellite in an approximately circular orbit 640 km above the surface of Earth? Suppose the satellite loses mechanical energy at the average rate of 1.4x10^5 J per orbital revolution. Adopting the reasonable approximation that the satellite's orbit becomes a "circle of slowly diminishing radius," determine the satellite's (c) altitude, (d) speed, and (e) period at the end of its 1500th revolution. (f) What is the magnitude of the average retarding force on the satellite? Is angular momentum around Earth's center conserved for (g) the satellite and (h) the satellite-Earth system?

    2. Relevant equations
    w=change in mechanical energy

    3. The attempt at a solution
    First and foremost, I've solved parts a-e correctly. I just need to get f-h.
    (1500 revs)((-1.4x10^5 J)/rev)=-2.1x10^8 J
    W=change in mechanical energy
    W=-2.1x10^8 J
    FDcos(x)=-2.1x10^8 J
    So F is definitely the unknown I have to solve for, therefore I should be able to get D and x. Do I just assume that x is 0 degrees? And for finding D, do I just choose one of the two radius values and multiply the amount of revs by the circumference?

    It seems to me as though the above way of solving is a little questionable. The only alternative would be a calc-based solution, but I am not quite sure how to go about that.
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you help with the solution or looking for help too?
Draft saved Draft deleted

Similar Discussions: Gravitation/Average Force Problem
  1. Magnetic Force problem (Replies: 0)