Originally Posted By: paul
-Unless acted upon by a net external force, a body, at rest, will remain at rest and a body, in motion, will remain in motion.

the pipe is itself a body.
if you are or are not capable of understanding that is your problem.

We all agree it is a body - but note you need an external force. Whether you're talking about a tank of air, a gun, or guys running up & down ladders, all of those forces are internal

Originally Posted By: paul
I have clearly shown all the possible forces involved and according to the forces

No, you've steadfastly ignored newtons laws, in particular newtons 3rd law.