What is the net force on the roof

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SUMMARY

The net force on a flat roof due to wind blowing at 35 m/s over an area of 240 m² is calculated using the equation P = Pat + 1/2 * p * v². Given the atmospheric pressure (Pat) of 100,000 Pa and air density (p) of 1.29 kg/m³, the total pressure (P) results in a net force (Fnet) of 1.9 x 10^5 N when only considering the dynamic pressure. The correct calculation focuses solely on the dynamic pressure component, confirming that the net force is indeed 1.9 x 10^5 N.

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

1/2 * 1.29 * 352 * 240 = ...
 
yes i am :)
 

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