According to Bernoulli's principle, ρv2/2
+ p = const, where ρ is the air density, v is the wind speed, and p
is the air pressure. If
is the air pressure at v = 0, then ρv2/2
+ p = p0.
The roof will be blown away after the difference p –
will exceed F/A where F is the limit force (20555 N) and A is the
area of the roof.
wind speed at which the roof will be blown outwards can be found from
the equation ρv2/2
Then v = √(2F / ρA) = √(2·20555 N / 1.29 kg/m3
· 3.3 m · 4.4 m) = 47 m/s.