Two balls, each of radius R, equal mass and density are placed in contact, then the force of gravitation between them is proportional to

Two spheres of equal radius r are touching each other. The force of attra tion between them is proportional to

Two identical solid copper sphere of radius R are placed in contact with each other. The gravitational force between them is proportional to.

Two identical spheres are placed in contact with each other. The force of gravitation between the spheres will be proportional to ( R = radius of each sphere)

Two identical spheres each of mass M and radius R are separated by a distance 3R. The force of attraction between them is proportional to

Two identical solid copper spheres of radius R placed in contact with each other. The gravitational attracton between them is proportional to

Two identical solid copper spheres of radius R placed in contact with each other. The gravitational attracton between them is proportional to