31 
“ 
897 
customary to assume thet it is also correct for a snhere. If it 
is intended to use bal! crusher gauges with short time constants, 
and if it tnen Deoehes necessary to use a ball whose mass is com- 
perable to that of the viston, this factor should be reexemined. 
In typical Buresu of Ordnance gauges with 5/32" and 3/8" balls, 
the masses of the svuheres were respectively 2% and 28% thet of 
tne corresponding pistons. It should also be pointed out that 
ignorance of the plastic response of the cooper ball or cylinder 
_is now the cause of the main uncertainty in the theory of pniston 
gauges. 
In g Cent 
Equation (15.4) 1g the incommessive, non-central solution. We 
repest it here. 
eens a Ma Hip bE R Sy 6 Re Te 
The corresponding compressive, central equation follows from 
Cit 2)Mendatisel)e ites 
(2.2) (M+RpZa) Zp thzp= 2h ht pon Cee (4-B)- 2n I 
This equation may be rewritten, when p AZ, negligible, and the 
incident pulse ir exponential, as 
ECO eS oor ae” +6) (2, (4-6) -2, 4] 
where 
8 = 2AT./m = initial acceleration of piston, 
