Air enters a convergence-divergence nozzle with 1.5 mpa pressure, 700 k temperature and very low velocity. there is a normal shock wave stands at the exit of the nozzle with mach 2.6. 3.a determine the pressure, temperature and density before and after the nsw 3.b quantify the entropy change across the nsw. 3.c determine the velocities before and after the nsw

On solidification from a melt, the polymer polyethylene forms a semi-crystalline spherulite structure. (i) sketch an individual spherulite and label the amorphous and crystalline regions. (ii) draw a schematic to show the changes in specific volume with temperature during cooling from the melt, comparing it to the theoretical extremes of fully crystalline and fully amorphous (indicate tm and tg)