Principles of rocket thrust
A question if I may.
I am in an ongoing debate with a university professor from a non aviation/aerospace background but versed in physics. I on the other hand am of a non university background but with 27 years as pilot with what I would like to believe a good understanding of the applied physics.
Regarding rocket thrust in space.
My understanding is that a rocket in space exerts a pushing force (thrust) that can be said to act as an opposing pressure upon the inner surface of the rocket nozzle/s and the engine as a whole. This I feel is a physical “pushing” force.
We both understand Newton’s 2nd and 3rd laws. My interpretation of the application specific to this is it is the accelerated mass which in turn places an opposing force. But I could be wrong.
The professor’s line on this is that it is simply the application of the 3rd law and there is no force, push or thrust as such. Simply it is the movement of mass in the opposing direction that causes accelerated forward movement.
Can there be thrust without push? At first glance it would appear absurd,.....but..?
My manuals don’t get this deep and everything I have pulled from the net appears to support my view. Perhaps my understanding has reached a limit and I am missing something or maybe the professor is thinking pure science and the real world application does exert a measurable force.
One method I use in my mind is to imagine a sealed pressure chamber a gas bottle if you will. Pressure is exerted equally in all directions. Create an opening at one point and pressure can no longer act at that point. The pressure force on the opposing side is now out of equilbrium and pushes the vessel forward.
Can someone throw some light on this?