Originally Posted by TangoKilo
It's part of the continuity equation, a rewriting of Newtons second law, you can see here:
Near the bottom of the page, under usage.
The equation Mark gave ignores the acceleration term.
The velocity term gives you a linear relationship, from maximum attainable thrust at 0 airspeed, down to zero thrust at whatever the exhaust velocity itself is.
Well, I see F = d(mv)/dt and I see F = m.a +mdot.v
but I don't see Thrust = mass_flow_rate * (Vexhaust - Vflight)
Can you briefly explain how you have rewritten Newton's second law?