By the end of the summer, Jason had saved enough money for college from his job as a waiter. He even had some money left over. Although he wanted both, he decided to buy a DVD player rather than a digital camera. Which of the following is the opportunity cost in this scenario? a the job b the DVD player c college d the digital camera

Amass of 1.5 kg of air at 120 kpa and 24°c is contained in a gas-tight, frictionless piston-cylinder device. the air is now compressed to a final pressure of 720 kpa. during the process, heat is transferred from the air such that the temperature inside the cylinder remains constant. calculate the boundary work input during this process.

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?

Abarometer contains mercury with a density of 13600 kg/m3. atmospheric conditions are 95.8 kpa and 20 °c at 20 °c, the vapor pressure of the mercury is 0.000173 kpa. the column of mercury will rise to a height of most nearly. select one: a)- 0.38 m b)- 0.82 m c)- 0.48 m d)- 0.72 m