Air flow isentropically through a supersonic convergent divergent nozzle with 0.5 kg/s. At the inlet, the pressure is 680 kPa and the temperature is 295 K, and the area is 6.5 cm2. If the exit area is 13 cm2 calculate: (1 point) a- The stagnation pressure and temperature. b- The exit Mach number. c- The exit pressure and temperature. d- The area and velocity at the throat. e- What will be the corresponding exit Mach number if the flow completely subsonic in the nozzle

A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?

What is the chief metrological difference between measuring with a microscope and with an electronic comparator? a. the microscope is limited to small workpieces.a. the microscope is limited to small workpieces. c. the comparator can only examine one point on the workpiece. d. the microscope carries its own standard.

Apure substance is a)-mixture of various chemical elements or compounds b)-substance that has a fixed chemical composition throughout c)-mixture that is homogeneous (such as air) d)-all the answers