\displaystyle
F=\frac{dp} {dt}=\frac {d} {dt}\left(\frac {m_0v} {\sqrt{1-\frac {v^2} {c^2}}}\right)=\frac {m_0a} {\sqrt{1-\frac {v^2} {c^2}}^3}=\frac {ma} {1-\frac {v^2} {c^2}}?