A storm blows wind across the top of a roof at a speed of v

A storm blows wind across the top of a roof at a speed of v = 29.8 m/s. Assume the air on the lower side of the roof (inside) is at rest and the roof is flat and has an area A = 36.1 m². The density of air is 1.28 kg/m³.

1)

What is the pressure differential across the top and bottom of the roof?

2)

What is the net lift force on the roof due to the storm?

Solution

The pressure is dP = 0.5*density*V²
1) dP =1/2*1.28*29.8^2 = 568.3456 Pa
This will be the pressure trying to lift the roof.
2) lift force, Fy = dP*A = 568.3456*36.1 = 20517.27616 N