Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The exit velocity of a compressed air cannon   The use of compressed air cannons in an undergraduate lab provides a way to
illustrate the cooperation of diverse physics concepts, such as conservation of
momentum, the work-kinetic energy theorem, expansion of gas, air drag, and
elementary Newtonian mechanics. However, recent proposals have disagreed as to
whether the expansion of the gas in the cannon should be modeled as an
adiabatic or an isothermal process. We built an air cannon that utilized a
diaphragm valve to release our pressurized gas and found that neither model
accurately predicted the exit velocity of our projectile. We present a new
model, based on the flow of air through the valve, that is in much better
agreement with our data.

20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
18
The categories of this paper are: econ
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th