In thermodynamics, a closed system can exchange heat and work (for example, energy), but not matter, with its surroundings.

momentum , thermodynamics , n such

so you were saying something?

although it may be hard to believe, a human sneeze travels at about 120 mph when it exits. the air moves faster, sometimes maybe 200 mph. some people have been able to prove that their sneeze traveled supersonic (breaking the sound barrier). most children sneeze at about 90 mph. adults from 40-50 have the fastest sneezes at sometimes over 800 mph.

the fastest sneezers 800 mph 40-50 yr old people

I guess that what I should get is a bunch of 40-50 year old people because they dont seem to have as hard a time at breaking the sound barrier when they sneeze. LOL

that way we wouldnt need a air tank that is pressurized to 100 psi , they could just sit up front facing backwards and
I could sprinkle pepper over them -- deep space here we come.

nozzel stuff

Rocket Nozzle Design: Optimizing Expansion for Maximum Thrust
A rocket engine is a device in which propellants are burned in a combustion chamber and the resulting high pressure gases are expanded through a specially shaped nozzle to produce thrust. The function of the nozzle is to convert the chemical-thermal energy generated in the combustion chamber into kinetic energy. The nozzle converts the slow moving, high pressure, high temperature gas in the combustion chamber into high velocity gas of lower pressure and temperature.
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Gas velocities from 2 to 4.5 kilometers per second can be obtained in rocket nozzles.
note : thats slightly faster than the speed of sound
wouldnt you say?
speed of sound 340 meters per second.

hmmm .... 4500 m/s - 340 m/s = 4160 meters per second faster than the slower speed of sound...
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The nozzles which perform this feat are called DeLaval nozzles (after the inventor) and consist of a convergent and divergent section. The minimum flow area between the convergent and divergent section is called the nozzle throat. The flow area at the end of the divergent section is called the nozzle exit area.

Hot exhaust gases expand in the diverging section of the nozzle. The pressure of these gases will decrease as energy is used to accelerate the gas to high velocity. The nozzle is usually made long enough (or the exit area great enough) such that the pressure in the combustion chamber is reduced at the nozzle exit to the pressure existing outside the nozzle. It is under this condition that thrust is maximum and the nozzle is said to be adapted, also called optimum or correct expansion. To understand this we must examine the basic thrust equation:

F = q Ve + (Pe - Pa) Ae

where F = Thrust
q = Propellant mass flow rate
Ve = Velocity of exhaust gases
Pe = Pressure at nozzle exit
Pa = Ambient pressure
Ae = Area of nozzle exit

The product qVe is called the momentum, or velocity, thrust and the product (Pe-Pa)Ae is called the pressure thrust.

Let us now consider an example. Assume we have a rocket engine equipped with an extendible nozzle. The engine is test fired in an environment with a constant ambient pressure. During the burn, the nozzle is extended from its fully retracted position to its fully extended position. At some point between fully retracted and fully extended Pe=Pa (see figure below).

Finally, we calculate the thrust,

F = q Ve + (Pe - Pa) Ae
F = 100 2,832 + (0.05x106 - 0.05x106) 0.409
F = 283,200 N

notice the above , take into account the
100 * 2832 !!!! because it equals 283,200
you add that amount to the ZERO from the Pe-Pa side and
you get the same number...


I might add that air can be compressed , combustible gasses
can not be compressed as high as air.

theres a big difference in compressed air and combustible gasses expanding , much higher velocities can be obtained
using compressed air than can be obtained by combustible gasses expanding.

if Uncle Al were here he would put you across his knee and give you a good lashing.

3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science.