Answer:
Scale reading for no wind [tex]W'=60N[/tex]
Explanation:
From the question we are told that
Area [tex]A= 2.0 m^2[/tex]
Weight of board [tex]W=80[/tex]
Velocity [tex]V=4.0m/s[/tex]
Density of air [tex]\delta= 1.25 kg/m3 .[/tex]
Generally the equation for pressure difference by Bernoulli equation is mathematically given by
[tex]dP=\frac{1}{2}pv^2[/tex]
[tex]dP=10Pa[/tex]
Generally force acting on the board by air is mathematically given by
[tex]F=\triangle PA[/tex]
[tex]F=(10)2=>20N[/tex]
Therefore
Scale reading for no wind W'
[tex]W'=W-F\\W'=80-20[/tex]
[tex]W'=60N[/tex]
Scale reading for no wind W'=60N
