A manufacturer of pressure vessels is worried about his steel fracturing abruptly as the chambers are loaded to high pressures because the steel is heavily cold-rolled with a very high yield strength (σy > 1 GPa). He decides to measure the fracture toughness of his steel using a thick-compact tension sample (Y = 1.12). He puts a 100 µm crack in the specimen, loads it in tension, and measures a fracture toughness of 10 MPa m^1/2.
a. What was the fracture stress during this experiment?

At steady state, air at 200 kpa, 325 k, and mass flow rate of 0.5 kg/s enters an insulated duct having differing inlet and exit cross-sectional areas. the inlet cross-sectional area is 6 cm2. at the duct exit, the pressure of the air is 100 kpa and the velocity is 250 m/s. neglecting potential energy effects and modeling air as an 1.008 kj/kg k, determine ideal gas with constant cp = (a) the velocity of the air at the inlet, in m/s. (b) the temperature of the air at the exit, in k. (c) the exit cross-sectional area, in cm2