Question

Compute the height in feet of a high building if the pressure at the ground floor is 30 in Hg and at the top of the building is 28.5 in Hg. Assume that the density of air is 0.075 lbm/ft3. thank you <3

Answer 1

we have to compute the height in feet of a high building if the pressure at the ground is 30 inch Hg and at the top of the building is 28.5 inch Hg. assuming that the density of air is 0.075lbm/ft³.

solution : pressure at the ground, P₁ = 30 inch Hg = 2.5 ft Hg

pressure at the top of tower, P₂ = 28.5 inch Hg = 2.375 ft Hg

now change in pressure, ΔP  = ρgh

⇒ 2.5 ft Hg - 2.375 ft Hg = 0.075 lb/ft³ × 32 ft/s² × h

⇒ 0.125 ft Hg = (2.4h) lbf/ft²

⇒ 106.089 lbf/ft² = (2.4h) lbf/ft²

⇒ h = 106.089/2.4 = 44.2 ft

therefore the height of the tower in ft is 44.2 ft