3–36E A spring-loaded piston-cylinder device is initially filled with 0.13 lbm of an R-134a liquid-vapor mixture whose temperature is -30F and whose quality is 80 percent. The spring constant in the spring force relation F = kx is 37 lbf/in, and the piston diameter is 12 in. The R-134a undergoes a process that increases its volume by 50 percent. Calculate the final temperature and enthalpy of the R-134a.[4 points]

Fluids at rest possess no flow energy. 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?

The drive force for diffusion is 7 fick's first law can be used to solve the non-steady state diffusion. a)-true b)-false