Potential Energy and gravitation

  1. Hello,

    Can someone please explain me:

    F=G m1xm2/R^2

    In potential energy U=mgh

    Generally it is also written that:

    U=-Gxm1xM2/r+K. How -G comes into play?

    Also Newton's above law of Gravitation in vector form is written as:

    F_12=-Gm1m2/r12^2 r12

    Here also how -G comes into play?

    Coming to Gravitation acceleration:
    If one of the masses is larger than the other, gravitational field is defines as:

    g=-GM/r^2xr_hat

    How again -G comes into play?

    If somebody can explain in a step by step method.............


    Thanks,

    -- Shounak
     
  2. jcsd
  3. russ_watters

    Staff: Mentor

    Upper-case G is the universal gravitational constant. It is basically just a conversion factor. It is negative by convention.
     
  4. Hello,

    What is the conversion factor?

    Does that mean the equation for G and -G are the same?

    -- Shounak
     
  5. tiny-tim

    tiny-tim 26,041
    Science Advisor
    Homework Helper

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