How Does Wind Speed Affect Roof Pressure in a Storm?

[Rikin25]

Homework Statement

The roof of a house has an area of 92.8 m^2. In a violent storm the air blows across the roof at a speed of 106.8 km/hr.

Homework Equations

Assuming that the air has a density of 1.25 kg/m^3, what pressure difference is created by the storm between the air outside and inside the house?

The Attempt at a Solution

Pressure/s = Area * density / speed (m/s)
= 92.8 * 1.25 / (106.8/3.6)
= 3.91 atm*s

how do i find the time?
or am i doing the whole thing wrong?

 

[Dr. Jekyll]

Maybe this has something to do with the Bernoulli's principle:

$$\frac{\rho v^{2}}{2}+\rho g h + p = const.$$

But then you don't need the surface...

 

[Moetasim]

Your equation is correct, but you are missing a conversion factor for the speed. The speed is given in km/hr, so you need to convert it to m/s by dividing by 3.6. Once you do that, you will get the correct answer for pressure difference.

As for finding the time, it is not necessary for this problem. The pressure difference is a result of the force of the air pushing against the roof, and the time is not a factor in this calculation. However, if you wanted to find the time it would take for the storm to create this pressure difference, you would need to know the force of the wind on the roof, which would require additional information such as the wind speed and the shape and orientation of the roof.