what is the relationship between "G" and "g"?
G is the gravitational constant. The gravitational force between two bodies of masses m1 & m2, separated by a distance d is given by:
F = G.m1.m2/d^2
The value of G is 6.674 X 10^(-11) N.m^2/kg^2. This is a universal constant.
g is the the acceleration due to gravity. This varies, even on the earth from place to place. An average value may be taken as 9.807 m/sec^2.