# newton's second law

1. ### Open Rocket d(m*V)/dt Calculation

Newton's Second Law is the time rate of change of Momentum equals the summation of forces (which is a vector equation). It appears that Open Rocket calculates d(m*V)/dt = m*dV/dt. Is this correct? Should it be d(m*V)/dt = m*dV/dt + V*dm/dt? If not, why not?