In A Test Experiment On A Model Aeroplane In A Wind Tunnel, The Flow Speeds On The Lower And Upper Surfaces Of The Wing Are v and  respectively. If The Density Of Air Is  and The Surface Area Of The Wing Is A, The Dynamic Lift On The Wing Is Given By     

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Question

In a test experiment on a model aeroplane in a wind tunnel, the flow speeds on the lower and upper surfaces of the wing are v and  respectively. If the density of air is  and the surface area of the wing is A, the dynamic lift on the wing is given by     

Solution

Correct option is

 

Let p1 and p2 be the air pressures on the upper and lower surfaces of the wing. Then from Bernoulli’s theorem we have  

        

where . Therefore, the pressure difference is

       

                    

 Force of dynamic lift = pressure difference  surface area of wing       

                                      .

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