Agas in a piston-cylinder assembly undergoes a compression process for which the relation between pressure and volume is given by pv^n=constant. the initial volume is 0.1(m^3), the final volume is (0.04m^3), and the final pressure is 2 bar. determine the initial pressure, in bar, and the work for the process, in kj, if (a) n = 0, (b) n =1, (c) n = 1.3. be sure to plot each process on a pv diagram.

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?

For a gate width of 2 m into the paper, determine the force required to hold the gate abc at its location.

With increases in magnification, which of the following occur? a. the field of view decreases. b. the ambient illumination decreases. c. the larger parts can be measured. d. the eyepiece must be raised.