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Each of the two wings of an aeroplane has area `30m^(2)`. The speed of the air on the upper and lower surfaces of theon the wing of aeroplane are `90 ms^(-1)` and `70 ms^(-1)` respectively. If the plane is in level flight at constant speed, find the uplift and the mass of the aeroplane. Given density of air `=1.29 kg m^(-3)`. |
Answer» Here, Area of each wing, `A=30m^(2)`, `v_(1)90 ms^(-1), v_(2)=70 ms^(-1), rho=1.29 kg m^(-3)` Since the aeroplane is in level flighth, so `P_(1)+(1)/(2)rho v_(1)^(2)=P_(2)+(1)/(2)rho v_(2)^(2)` or `P_(2)=P_(1)=(1)/(2)rho(v_(1)^(2)-v_(2)^(2))=(1)/(2)xx1.29(90^(2)-70^(2))` `2064 Nm^(-2)` Upward from both the wings of aeroplane `F_(1)=(P_(2)-P_(1))xx2A=2064xx2xx30=123840 N` `=1.24xx10^(5) N` Mass of the plane, `M=(F)/(g)=(1.24xx106(5))/(9.8)` `=1.26xx10^(4) kg` |
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