1271 
a way of determing the maximum velocity, B,from the given 
peak pressure. This can be done by means of the following 
formula, which follows from (15.2) 
1 
B=ae- [S-na-3 Siig Spader Ge am 
where t= P41 
Pin= effective peak pressure in incident pulse. 
It may be noted that equation (16.3) provides a relation 
between p, and B which is not consistent with (18.1). Equa- 
tion (18.1) is for a shock, whereas (16.3) is the progressive 
condition; as mentioned before (par. 3) they are not compatible, 
and decay must always be expected. The procedure followed 
here is this: t is regarded oa given. From (18.1) B is found. 
From (17.1) u is found. (17.1) and (17.2) then completely de- 
termine the wave. De is the given effective peak pressure. Let Pm, 
be the approximate effective peak pressure computed from (16.3). 
The difference (D, - P,,) Pn 4s shown in Table 2; it is seen 
to bé unimportant. 
TABLE 2 
leu: 0.0005 0.0002 
1.0 0.0020 0.0008 
19. The differential equations (14.4) and (14.5) can 
at once be solved in M, subject to the boundary conditions 
(17.1) and (17.2) if the approximation is introduced that the 
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