m0=(1/2)mc2m_{0}=(1 / 2) m c^{2}m0=(1/2)mc2
m0=2 m\mathrm{m}_{0}=2 \mathrm{~m}m0=2 m
m=2m0m=2 m_{0}m=2m0
m0=2mc2\mathrm{m}_{0}=2 \mathrm{mc}^{2}m0=2mc2