For example then talking about the rocket the trust is:(adsbygoogle = window.adsbygoogle || []).push({});

F_thrust = u*dm/dt

where u is speed of the gases relative to the rocket, and dm/dt rate of change of ejected mass of gases.

Now if the rocket is being launched vertically so force of gravity acts upon it and:

F_net = F_thrust - mg = u*dm/dt - mg

According to the 2nd Newton's law:

F_net = dp/dt = v*dm/dt + m*dv/dt = v*dm/dt + ma

If comparing these equations:

ma=-mg in this case:

should that be interpreted that the acceleration a is caused by the forces other then thrust.

And is it possible to write:

F_net = m*dv/dt + F_other = F_thrust + F_other

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# How to interper thrust of the rocket

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