# Problem: A hurricane wind blows across a 7.50 m x 11.2 m flat roof at a speed of 190 km/hr.a) Is the air pressure above the roof higher or lower than the pressure inside the house? Explain.b) What is the pressure difference?

###### FREE Expert Solution

The equation of continuity:

$\overline{){\mathbf{\rho }}{{\mathbf{A}}}_{{\mathbf{1}}}{{\mathbf{V}}}_{{\mathbf{1}}}{\mathbf{=}}{\mathbf{\rho }}{{\mathbf{A}}}_{{\mathbf{2}}}{{\mathbf{V}}}_{{\mathbf{2}}}}$

Bernoulli's equation:

$\overline{){{\mathbf{p}}}_{{\mathbf{1}}}{\mathbf{+}}\frac{\mathbf{1}}{\mathbf{2}}{\mathbf{\rho }}{{{\mathbf{v}}}_{{\mathbf{1}}}}^{{\mathbf{2}}}{\mathbf{+}}{\mathbf{\rho }}{\mathbf{g}}{{\mathbf{y}}}_{{\mathbf{1}}}{\mathbf{=}}{{\mathbf{p}}}_{{\mathbf{2}}}{\mathbf{+}}\frac{\mathbf{1}}{\mathbf{2}}{\mathbf{\rho }}{{\mathbf{v}}_{\mathbf{2}}}^{{\mathbf{2}}}{\mathbf{+}}{\mathbf{\rho }}{\mathbf{g}}{{\mathbf{y}}}_{{\mathbf{2}}}}$

a)

From the equation of continuity, the speed of the hurricane wind increases at the outside of the roof.

Inside the roof, the pressure is greater and the velocity is smaller.

80% (403 ratings) ###### Problem Details

A hurricane wind blows across a 7.50 m x 11.2 m flat roof at a speed of 190 km/hr.

a) Is the air pressure above the roof higher or lower than the pressure inside the house? Explain.
b) What is the pressure difference?