Question

what is the relation between gravitational constant G and force of gravity​

Answer 1

Cavendish experiment

…of the value of the gravitational constant, G. In Newton's law of universal gravitation, the attractive force between two objects (F) is equal to G times the product of their masses (m1m2) divided by the square of the distance between them (r2); that is, F = Gm1m2/r2.

Answer 2

F = GMm/r²,

where F is the force of gravity...

and G is the universal gravitational constant...