Question

Two identical solid copper spheres of radius R are placed on contact with each other . The gravitational attraction between them is proportional to what? 1 ) R² 2)1 / R² 3) R ⁴ 4)1/ R ⁴

Answer 1

Gravitational attraction between two objects =
F = G M1 M2 / d²

where d = distance between the centers of mass of the two objects
= 2 R

F = G M² / (2R)² = (G M²/4) R⁻²

So the force α (2 R)⁻² or R⁻²
option (2)