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discontinuity in velocity where it crosses D. M, and 
M are the regions between D and the x-axis and t-axis 
respectively. 
13. The problem may be stated in this way. The 
following conditions are given: 
(A) Boundary conditions on axes and on D. 
(1. Distribution of pressure, p, and 
velocity, uy, on x-axis. This is the 
distribution of pressure and velocity 
behind the shock front when it strikes 
the wall. 
(2. u = O on t-axis, since the wall is 
rigid. 
(3. The shock equations across the dis- 
continuity, D, 
(a conservation of mass. 
(b conservation of momentum 
(c conservation of entropy (an 
approximation) 
(B Equations to be satisfied in M, and in M 
(1. conservation of mass. 
(2. conservation of momentum 
(3. conservation of entropy (an approximation) 
We wish to find the pressure, p, and velocity, u, as functions 
of x and t in both regions, M, and M. In addition, we shall 
find the equation of the curve D, which separates them. 
Se 
