In free space, a particle $A$ of charge $1\mathrm{ }\mathrm{\mu }\mathrm{C}$ is held fixed at point $P$ . Another particle $B$ of the same charge and mass $4\mathrm{ }\mathrm{\mu }\mathrm{g}$ is kept at a distance of $1\mathrm{ }\mathrm{m}\mathrm{m}$ from $P.$ If $B$ is released, then its velocity at a distance of $9\mathrm{ }\mathrm{m}\mathrm{m}$ from $P$ is:
[Take $\frac{1}{4\mathrm{\pi }{\mathrm{ϵ}}_0}=9\times {10}^9\mathrm{ }\mathrm{N}\mathrm{ }{\mathrm{m}}^2 {\mathrm{C}}^{-2}$ ]