The diameter of the hollow core of a solid-propellant grain remains axially uniform during burning. The length is 5 m, and initially its inner diameter is 0.37 m; the outer diameter of the grain is 0.82 m. The burning rate r is 1.2 cm/s, which as a first approximation may be assumed uniform over the entire inner surface of the grain. The grain density is 1875 kg/m^3. The combustion chamber pressure and gas temperature downstream of the grain are 2.17 MPa and 2580 K, respectively. Neglecting the effects of friction, estimate, at the beginning and end of combustion, the static pressure ratio p2/p1 along the length of the grain and the Mach number M2 at the downstream end of the grain. The gas specific heat ratio and molecular weight are 1.2 and 20.