$\begin{align}  & {{w}_{E}}=\Delta k \\  & E\left| q \right|d\cos \theta =\not{{{\overset{0}{\mathop{k}}\,}_{2}}}-{{k}_{1}}\Rightarrow {{10}^{4}}\times 1/6\times {{10}^{-19}}\times 8\times {{10}^{-2}}\times \not{\overset{-1}{\mathop{\cos 180}}\,}=-\frac{1}{2}\times 1/6\times {{10}^{-27}}\times {{v}^{2}}\to {{v}^{2}}=16\times {{10}^{10}}\Rightarrow v=4\times {{10}^{5}}{}^{m}/{}_{s} \\ \end{align}$