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!

Gravitational and electric fields

  1. Oct 20, 2009 #1
    1. The problem statement, all variables and given/known data
    By considering the centripetal force which acts on a planet in a circular orbit, show that T^2 is proportional to R~^3 where T is the time taken for one orbit around the sun and R is the radius of the orbit


    2. Relevant equations
    I'm thinking keplers third law?



    3. The attempt at a solution
    C=2piR

    P=2piR/ sqrt*GMm/r

    rearranged to give P = 2pi sqrt*R^3/GM

    Lost now..
     
  2. jcsd
  3. Oct 20, 2009 #2


    Where did that expression come from?


    Find an expression for the radial acceleration in terms of the orbital speed and R.

    Then use Newton's second law.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Gravitational and electric fields
Loading...