The atomic radii of a divalent cation and a monovalent anion are $0\mathrm{.}10nm$ and $0\mathrm{.}147nm,$ respectively.

$($a$)$ Calculate the force of attraction between these two ions at their equilibrium interionic separation $($i$.$e$.,$ when the ions just touch one another$).$

$($b$)$ What is the force of repulsion at this same separation distance?