theres a pvc pipe thats completely sealed in space like 10 meters long and its filled with air. Theres a tank inside the pipe filled with super compressed air. What would happen if the tank released all its compressed air in one direction and flew forward crashing into the front of the pvc pipe? Would the compressed air shooting out of a nozzle suddenly dissipate into the less dense air inside the tube or would it continue to the back of the tube and crash into it. Also when the air tank flew forward, and crashed into the front of the pvc pipe would it carry the pipe along with it, since it has so much more mass than the plastic piping?
There is a general principle about internal forces that applies to situations like this and what it amounts is that the center of mass can never move. It's like that movie Gravity; in space, a stationary closed system can't make any net motion. If the cylinder shoots off in one direction the pipe will go in the other with equal momentum, and when it crashes into the end, both parts will reverse direction. And the two parts will bounce back and forth off each end until heat from the collisions dissipates all the energy.
