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: Calculate the magnitude of the gravitational force

  1. Oct 4, 2007 #1
    1. The problem statement, all variables and given/known data

    Four 9.0 kg spheres are located at the corners of a square of side 0.72 m. Calculate the magnitude of the gravitational force on one sphere due to the other three.

    2. Relevant equations


    3. The attempt at a solution

    I figured out the force the each of the two spheres perpendicular to the corner one by doing Fg=[(6.67e-11)(9)(9)]/[.72^2]=1.04e-8. then i used the pathageon theorum to find the radius to the sphere in the opposite corner of the square by doing square root of .72^2+.72^2=1.02. I am now having trouble finding the force of the two corner balls pulling at a 45 degree angle towards the middle of the square.
  2. jcsd
  3. Oct 5, 2007 #2


    User Avatar
    Homework Helper

    For the 3rd force at a distance of 1.02 m... apply the force formula to get the magnitude of the force... ie Gm1m2/(1.02)^2

    then what is the x-component of this force... what is the y-component of this force...

    add up the x-compoents of all 3 forces.

    add up the y-components of all 3 force.

    then you have the x-component and y-component of the net force... get the magnitude...
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook