Relativistic mass $\displaystyle m(v)=\frac{m_o}{\sqrt{(1-(v/c)^2}}$
$m_o$ = mass of object measured at rest
$c$ = speed of light ($3\times 10^8\;m/s$)
$v$ = speed
If the total relativistic energy of an object is given by $E=mc^2$, then find the second-order Taylor approximation of $E(v)$. The zeroth-order term is called the "rest energy." What is the second-order term usually called?