Fig.10.11: Comparison of V curve vs stability ratio curve

Stability factor being given by

Let rm be the separation distance between 2 particles at which the maxima in energy occurs. It can be approximated that centre to centre distance (r) between particles is the sum of r_m and radii of the 2 particles. Thus,

(10.28)

Expanding u by Taylor series about um the maximum of energy we get

(10.29)

as r_m is the point where the energy is maximum. Substituting the values from equation (10.28) and (10.29) in equation (10.27) we get

(10.30)