Question

what is compressed more iron piece and air. why

Answer 1

Heya,

Air can be compressed more as it has high intermolecular spaces, least force of attraction and high kinetic energy.

HOPE IT HELPS :-))

Answer 2

A compressed air system's piping serves many purposes. The most obvious is to transport the air from the supply side of the system to the downstream equipment. It also provides limited storage capacity and controls velocity to and from various process parts of the system. A variety of  piping materials that can be used, as well as many approaches to assembling them. Many types and styles of valves  can be used within the air system. Different piping configurations can also be used to suit a broad range of needs. One thing is for sure: there are rarely straightforward answers regarding piping and piping systems.