Which of the following statements about pitot-static systems is false? a). a pitot probe measures the total pressure of the freestream. b). a static port measures the pressure of the freestream air. c). a pitot-static system measures the dynamic pressure using the formula dynamic pressure = total minus static. d). dynamic pressure is equal to the static pressure at a stagnation point

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?