Tall buildings can develop a significant difference in pressure between the inside and the outside of the building. Air lock entrances are used at the ground level so the pressure at the ground floor is not the same as atmospheric pressure. Assume that a skyscraper does not use an airlock entrance and that the temperature inside a 300 m skyscraper is 21°C and the temperature outside is a uniform 0°C. Assume standard atmospheric pressure at the base of the building and that the pressure is the same inside and outside at ground level. At the top of the building, calculate the pressure difference between the inside and the outside

(a) assuming air is incompressible, (b)taking account of the compressibility. (c) Is the compressibility of air important in this problem? (d) What is the equivalent height of a water column for this pressure difference? (e) If someone opens a window on the top floor will air go in or out?

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