c
ઝડપ \( = {\rm{0}}{\rm{.8c}}\)
\({\rm{m}} = \frac{{{{\rm{m}}_{\rm{0}}}}}{{\sqrt {{\rm{1 - }}\frac{{{{\rm{v}}^{\rm{2}}}}}{{{c^2}}}} }} = \frac{{{n_0}}}{{\sqrt {1 - \frac{{{{0.64}^2}}}{{{c^2}}}} }}\,\,\,;\)
\(m = \frac{{{m_0}}}{{0.6}} = \frac{5}{3}{m_0}\)