What is the net force on the roof

[robvba]

Homework Statement

If wind blows at 35 m/s over a house, what is the net force on the roof if its area is 240 m2 and is flat?

Homework Equations

Pat + 1/2 * pair * v^2

The Attempt at a Solution

wind velocity - v - 35
area of roof - A - 240
density of air - p - 1.29
atmospheric pressure - Pat - 100,000

Fnet=?

P = total pressure = Pat + 1/2 * p * v^2
Fnet = P * A = 24,200,000 N

but answer provided was 1.9 * 10^5 N

 

[LowlyPion]

Aren't you just interested in the dynamic pressure term across the area of the roof?

1/2 * 1.29 * 35² * 240 = ...

 

[robvba]

yes i am :)