\(-\frac{\mathrm{GM}_{\mathrm{e}} \mathrm{m}}{10 \mathrm{R}}+\frac{1}{2} \mathrm{mv}_{0}^{2}=-\frac{\mathrm{GM}_{\mathrm{e}} \mathrm{m}}{\mathrm{R}}+\frac{1}{2} \mathrm{mv}^{2}\)
\(+\frac{9}{10} \times \frac{\mathrm{GM}_{\mathrm{e}} \mathrm{m}}{\mathrm{R}}+\frac{1}{2} \mathrm{mv}_{0}^{2}=\frac{1}{2} \mathrm{mv}^{2}\)
\(\frac{9}{10} \times \frac{1}{2} \mathrm{M} \times \mathrm{v}_{\mathrm{e}}^{2}+\frac{1}{2} \mathrm{mv}_{0}^{2}=\frac{1}{2} \mathrm{mv}^{2}\)
\(\mathrm{v}^{2}=\frac{9}{10} \mathrm{v}_{e}^{2}+\mathrm{v}_{0}^{2}\)
\(=\frac{9}{10} \times(11.2)^{2}+(12)^{2}\)
\(\mathrm{v}^{2}=112.896+144\)
\(\mathrm{v}=16.027\)
\(\mathrm{v}=16 \mathrm{km} / \mathrm{s}\)