1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Gravitational force between the Earth and the Sun

  1. Feb 15, 2012 #1
    1. The problem statement, all variables and given/known data
    The question is what is gravitational force between the Earth and the Sun.
    We are given the formula F = Gm1m2/d2. I found the mass of the sun and the earth the gravitational constant and the distance. my issue is the G of the equation.

    G=6.674 x 10^-11 m^3 / kg s^2

    my issue is i cannot solve the problem without knowing what the m,kg,and s are of G. i have seen people answer this the following way

    2. Relevant equations

    (6.674 x 10^-11 m^3 / kg s^2)(1.9891 x 10^30 kg)(5.9736 x 10^24 kg) / (1.503 x 10^11 m)^2
    The answer they got was: 3.510 x 10^22 N

    This confuses me because i dont know what their N is either.

    The question/TLDR
    My guess is ks is just kilograms and m is maybe m2.

    What are the variables in gravitational constant.
    G= 6.674 x 10^-11 m^3 / kg s^2

    m=? kg=? s=?

    Also First post :D
    Last edited: Feb 15, 2012
  2. jcsd
  3. Feb 15, 2012 #2

    Ray Vickson

    User Avatar
    Science Advisor
    Homework Helper

    m = meters (unit of distance), kg = kilograms (unit of mass), s = seconds (unit of time), N = Newtons (unit of force). They are units, not numbers.

    Admittedly, using 'm' and 's' can lead to confusion sometimes, especially since the letter 'm' is often used in Physics to denote a mass, and 's' is often used in other ways, too.

  4. Feb 15, 2012 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    Hello yumito. Welcome to PF !
  5. Feb 22, 2012 #4
    thanks that helped me out i was quite confused haha. also how do i make the thread solved?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook