Estimating Weight of 6.5m x 15m Flat Roof in Wind

[itryphysics]

Homework Statement

A 190 km/h wind blowing over the flat roof of a house causes the roof to lift off the house.
If the house is 6.5m x 15m in size, estimate the weight of the roof. Assume the roof is not nailed down.

Homework Equations

Bernoulli's equation : P1 + 1/2pv^2 +pgy = P2 + 1/2pv^2 + pgy

The Attempt at a Solution

i reduced the equation down to 1/2pv^2 to get pressure which numerically was 1671.3 and then i multiplied that by the area which i calculated to be 97.5 m^2, to get the force.

I was clueless on how to approach this problem, but I am even more confused now. please help.

 

[HallsofIvy]

You are done, aren't you? The problem asked for the weight of the roof. In order to lift something, you must apply a force (at least) equal to its weight. If the force you calculated was just enough to lift the roof, then that is the weight of the roof!