m= \frac{(E_1) + (E_2) + (E_3) +...}{c^2}= \frac{({m_1}c^2 + \frac{1}{2} {m_1} {v_1}^2) + ({m_2}c^2 + \frac{1}{2} {m_2} {v_2}^2) + ...}{c^2}