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!

Force of gravity between two objects

  1. Mar 21, 2005 #1
    hi i am stuck and dont know what to do next or if i am even on the right path. could someone help me please!!!!!!!!!!!!!! :cry:

    my question is what is the force of gravity between two 100kg cars separated by a distance of 25m on an interstate highway?
    I started out like this:


    fg=Gm1m2+6.67 x 10-11Nm2 x (1000kg) (1000kg)
    r2 kg2 (25m)2



    G=6.67 x 10-11 Nm2
    kg2



    then i dont know what to do or if this is even close






    thanks to anyone with the time to help.
     
  2. jcsd
  3. Mar 21, 2005 #2

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    Just plug in the CORRECT values in the formula for F:
    [tex]F=\frac{Gm_{1}m_{2}}{r^{2}},G=6.67*10^{-11}\frac{Nm^{2}}{kg^{2}},r=25m,m_{1}=m_{2}=100kg[/tex]

    Query:Check the value of the mass for each car; are you sure it is 100kg, rather than 1000kg?
     
  4. Mar 21, 2005 #3
    It gives me an extremely small result. Something like 0.0000001 N. It makes sense btw.
     
    Last edited: Mar 21, 2005
  5. Mar 21, 2005 #4

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    Would you expect anything else?
     
  6. Mar 21, 2005 #5
    No because gravity weaks considerably with the distance (action at a distance).
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?