Question

Two metal spheres of same material and radius 'r' are in contact with each other. The gravitational force of attraction between two spheres is given by (k is constant)

A)F=kr⁴
B)=F=k/r²
C)F=k/4r²
D)F=kr²

Answer 1

Given diameter = d, Hence r = d2d2
Ans : directly proportional to the fourth power of the radius.
F = Gm1m2r2Gm1m2r2
F=G(43πr3)ρ(43πr3)ρr2F=G(43πr3)ρ(43πr3)ρr2
F∝r4F∝r4
F = kr4
(Mass=volume *dencity)
Volume of sphere=4/3 (pi)r^3