Newton's law of gravitation

Newton's Law of Gravitation:

               Every particle of matter in the universe attracts every other particle with a force which is directly proportion  -al to the square of the distance between the two particle.

               Hence, the gravitational force of attraction between two point masses ‘M’ and ‘m' separated by a distance ‘r' is given by:

    F ∝ Mm    and    F  ∝ 1/r²    .•.  F  ∝  Mm/r²
   
                    F=-G Mm             ..........(1)
                                r²
 

  Where, G= Gravitational Constant ,
                 M and m are two point masses,                         separated by a distance ‛r’.

                 The negative sign shows that the Gravitational force is always attractive.

             Gravitation Constant G : In eq. (1) if, M=m and r=1 then F=G (Numerically).

Definition: The universal G gravitational constant (G) is equal to the force of attraction between two bodies each of unit mass, lying ar a unit distance apaet.

              G=6.67×10-¹¹ N.m²/kg²  in S.I units

              The S.I Unit of G is newton.m²/kg²
              or N.m/kg²

Dimension of G is : [M¹L¹T-²] [L²]
                                                [M²]

                                     =   [M-²L³T-²]