50 the emissivity of galvanized steel sheet, a common roofing material, is s = 0.13 at temperatures around 300 k, while its absorptivity for solar irradiation is as = 0.65. would the neighborhood cat be comfortable walking on a roof constructed of the material on a
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a. if a dryer is designed to operate with an electric power consumption of pelec = 500 w and to heat air from an ambient temperature of ti = 20°c to a discharge temperature of to = 45°c, at what volu- metric flow rate 'e should the fan operate? heat loss from the casing to the ambient air and the surround- ings may be neglected. if the duct has a diameter of d = 70 mm, what is the discharge velocity vo of the air? the density and specific heat of the air may
day when gs = 750 w/m2, t00 = 16°c, and h = 7
w/m2 · k? assume the bottom surface of the steel is
insulated.
be approximated as p = 1.10 kg/m3 and cp
j/kg · k, respectively.