Question

A house has a flat roof of area 400 m^2. The windows of the house are tightly closed such that the air pressure in the house remains at the level10^5 N/m^2 with density 1.3kg/m^3, more or less independent of what happens outside. A tropical storm results in the sudden onset of a horizontal wind over the roof at a ground speed of 20 m/s. The roof, which is not nailed to the walls, is slightly lifted during the high wind. a) Name and explain the principle responsible for the lifting of the roof. b) Find the approximate mass of the roof. c) After the storm, the roof, which is one-fourth of the mass of the house, is repositioned and nailed to the walls. How fast must a new storm blow to lift the entire house? Use g = 9.8 m/s^2.

Answer 1