The assembly has the diameters and material indicated. If it fits securely between its fixed supports when the temperature is T1=70℉, determine the average normal stress in each material when the temperature reaches T1=110℉. (Young’s Moduli are 10.6×10^6 kip/in^2, 15×10^6 kip/in2, and 28×10^6 kip/in^2 for aluminum, bronze, and steel, respectively. The coefficients of thermal expansion are 12.8 μstrain/°F, 9.60 μstrain/°F, 9.60 μstrain/°F for aluminum, bronze, and steel, respectively.)

Acompressor receives the shaft work to decrease the pressure of the fluid. a)- true b)- false

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

Steam enters a converging nozzle at 3.0 mpa and 500°c with a at 1.8 mpa. for a nozzle exit area of 32 cm2, determine the exit velocity, mass flow rate, and exit mach number if the nozzle: negligible velocity, and it exits (a) is isentropic (b) has an efficiency of 94 percent