In atest experiment on a model aeroplane in a wind tunnel , the flow speeds on the upper and lower surfaces of the wing are 70ms^(-1)and63ms^(-1) respectively . What is the lift on the wing if its area is 2.5m^(2) ? Take the density of air to be 1.3kgm^(-3).

In atest experiment on a model aeroplane in a wind tunnel , the flow s

1.	In atest experiment on a model aeroplane in a wind tunnel , the flow speeds on the upper and lower surfaces of the wing are 70ms^(-1)and63ms^(-1) respectively . What is the lift on the wing if its area is 2.5m^(2) ? Take the density of air to be 1.3kgm^(-3).
Answer» Solution :Let `v_(1),v_(2)` be the speeds on the upper and lower surface of the WING of aeroplane and `P_(1)andP_(2)` is the pressure on upper and lower surface of the wing respectively and height from ground are `y_(1)andy_(2)` respectively. `thereforev_(1)=70ms^(-1),v_(2)=63ms^(-1)`, `y_(1)=y_(2),RHO=1.3kgm^(-3)` From Bernoulli.s equation, `P_(1)+(1)/(2)rhov_(1)^(2)+rhogh_(1)=P_(2)+(1)/(2)rhov_(2)^(2)+rhogh_(2)` `thereforeP_(1)-P_(1)=(1)/(2)rho(v_(1)^(2)-v_(2)^(2)) ""[becauseh_(1)=h_(2)]` `therefore`Upward froce on wings, `F=(P_(2)-P_(1))A` `thereforeF=(1)/(2)rho(v_(1)^(2)-v_(2)^(2))A` `=(1)/(2)xx1.3xx[70^(2)-63^(2)]xx2.5` `=(1)/(2)xx1.3xx[4900-3969]xx2.5` `=(1.3)/(2)xx931xx2.5` `=1512.9N` `=1.513xx10^(3)N`