Two men each have a mass of 90 kg. if the gravitational force between them is 8.64 10-8 n, how far apart are they? g = 6.67 × 10-11 n⋅(m/kg)2

Applicable formular:

F = Gm1m2/d^2, where F = gravitational force, m1 & m2 = mass of the two bodies, G = Gravitational constant, d = distance between the bodies.

Substituting;

8.64*10^-8 = (6.67*10^-11*90*90)/d^2
d^2 = (6.67*10^-11*90^2)/(8.64*10^-8)
d = Sqrt [(6.67*10^-11*90^2)/(8.64*10^-8)] = 2.5 m

The two men are 2.5 m apart.