\({V_c} = - \frac{{3GM}}{{2R}}\)
\(\frac{1}{2}m{v^2} = m\left( {{V_s} - {V_c}} \right)\)
\({v^2} = 2\frac{{GM}}{R}\,\left( {\frac{3}{2} - 1} \right)\) [As \({v_e} = \sqrt {2gR} \)]
\( = \frac{{GM}}{R} = gR\)
\( = \frac{{v_e^2}}{2}\)
\(\therefore v = \frac{{{v_e}}}{{\sqrt 2 }}\)