9–107. the suspension bunker is made from plates which are curved to the natural shape which a completely flexible membrane would take if subjected to a full load of coal. this curve may be approximated by a parabola, y = 0.2x2. determine the weight of coal which the bunker would contain when completely filled. coal has a specific weight of g = 50 lb> ft3, and assume there is a 20% loss in volume due to air voids. solve the problem by integration to determine the cross-sectional area of abc; then use the second theorem of pappus–guldinus to find the volume.

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?

Agas mixture consists of 8 kmol of h2 and 2 kmol of n2. determine the mass of each gas and the apparent gas constant of the mixture.

What is the heat treatment of metals? what is the benefit of it? why and how it's useful? answer in details, do not write by hand.