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Homework Help: Got a doosie here, Angular acceleration, time and radius.

  1. Oct 5, 2011 #1
    1. The problem statement, all variables and given/known data
    An earth satellite moves in a circular orbit with an orbital speed of 6200 m/s. Find the time of one rotation as well as the radial acceleration of the satellite in orbit.


    2. Relevant equations
    Ac= V^2/R
    mAc=mg
    V= 2(pi)R/t


    3. The attempt at a solution

    Ok, I've gone every which way I can with this problem. I don't know how to go about it. I've drawn an FBD and the only forces I can see acting on it are the weight of the satellite and the Ac. I don't know if there is supposed to be another variable that is assumed, like the radius of the earth, or if gravity acts upon the satellite at 9.8 m/s^2 like it would on earth...I'm pretty lost here. Any advice on how to start?
     
  2. jcsd
  3. Oct 5, 2011 #2
    I believe the orbital speed is the tangential speed of the satellite.

    What is one rotation? (quickly, go back to your unit circle!)
     
  4. Oct 5, 2011 #3
    One rotation is 2(pi) radians, iirc.
     
  5. Oct 5, 2011 #4
    I still don't know where to go from there, it seems like I need another variable somehow...
     
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