1278 
abe =X ta + 6 te” 
A (tg) =H a, + Se a (ta), 
according to (22.2) and (23.2),respectively. The time t, 
is a retarded value of the time ty, since ty - te is the 
time required for a given value of Q to propagate itself 
.- from the shock front to the wall. If the shock and Q both 
travelled with the velocity of sound (unity), then one would 
have exactly tg = 0.5 ty. This relation is nearly satisfied 
in any case. 
256 Our aim is to calculate p(0,t;) from tp. For this 
purpose it is sufficient to find Q (O,tp)s because at the wall, 
where u = O, 
ce = LQ, (2561 
and from c the pressure follows according to the equation 
2 
p=We sa 
as one may calculate from (14.3) and (14.8). It is con- 
(25.2 
venient to combine (25.1) and (25.2) 
2 
B= wilt a] yu (25.3 
Since Q (0,t,) is known from the preceding paragraph, this 
equation completes the determination of p(0,tp) as a function 
of the The problem will be earried no further here, but it 
is possible to determine all quantities of interest in the 
complete region, M, by similar methods. 
aie In this paragraph all formulas necessary for the 
calculation of the pressure-time curve on the wall are 
= Be & 
