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

Gravitation force at a point

  1. Dec 10, 2011 #1
    1. The problem statement, all variables and given/known data
    The question is presented as picture.

    2. Relevant equations
    We do not have the radius of the cavity and the position of the m. How can we find the force acted on it?

    3. The attempt at a solution
    r=1/(M-m)*Ʃmr=1/(M-m)*4/3ρR'^3*r where m is the mass of cavity ,R' is the radius of the cavity and r is the position of center of mass. But I can't find R'.

    Attached Files:

  2. jcsd
  3. Dec 10, 2011 #2

    Filip Larsen

    User Avatar
    Gold Member

    Can you solve this problem if there was no cavity? If so, perhaps you can think of a way to model the problem so that the force on the point mass is the sum of two contributions, one from the big sphere and a "negative" from the small sphere?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook