Originally Posted By: paul
applied at the end of the pipe 500 ft away the force that
causes the pipe to move is greater than any force that
could slow or stop the pipe.


It comes back to the old issue of the time the force is applied for. Now also the area it's applied over. A tiny pressure over a larger area for a long time can cause a lot of acceleration/decelleration.

Also, there would be some longitudinal force applied by the air interacting with the sides of the pipe. If you make the pipe longer to reduce the force on the end cap, you're achieving that by increasing the force on the walls.

Imagine it's millions of ball bearings instead of air. Then what'll happen to them?