Either way, no motion further than the length of the pipe.

this is where your thinking is flawed , you somehow think the pipe will stop when it has traveled its lenght.

that doesnt really make much sence.

and you base that on the air that strikes the pipe after leaving the nozzle.

For a long pipe most of the air's momentum will be transferred to the pipe walls

this also makes no sence , the air will expand into the entire inside area of the pipe so most of the air will
not "magically" as you like to say , expand out to the
the pipe walls.

I seriously doubt that the air that does rub against the walls of the pipe would cause much resistance to movement.

and the air that actually touches the walls is probably only around .005 percent of the volume of air that leaves the air tank.

so far you havent offered any meaningful opposition.

further than the length of the pipe.

and one more thing , if the air is released very slowly
the pipe could actually travel several times its lenght before the air tank empties or equalizes.

have you ever considered that?

Edited by paul (03/09/11 05:13 AM)
3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science.