\(E = \frac{\lambda }{{2\pi {\varepsilon _0}r}}\)
\(\Delta \mathrm{V}=\frac{\lambda}{2 \pi \varepsilon_{0}} \ln \left(\frac{\mathrm{r}_{0}}{\mathrm{r}}\right)\)
\(\frac{1}{2} m v^{2}=\frac{-q \lambda}{2 \pi \varepsilon_{0}} \ln \left(\frac{r_{0}}{r}\right)\)
\(v \propto \sqrt{\ln \left(\frac{r}{r_{0}}\right)}\)