Air of density 1.2 kg m-3 is blowing across the horizontal wings of an aeroplane in such a way that its speeds above and below the wings are 150 ms-1 and 100 ms-1, respectively. The pressure difference between the upper and lower sides of the wings, is :

Question

Air of density 1.2 kg m-3 is blowing across the horizontal wings of an aeroplane in such a way that its speeds above and below the wings are 150 ms-1 and 100 ms-1, respectively. The pressure difference between the upper and lower sides of the wings, is : (A) 60 Nm-2 (B) 180 Nm-2 (C) 7500 Nm-2 (D) 12500 Nm-2

Tardigrade Admin · Accepted Answer

Pressure difference P2-P+1=(1/2)ρ(v22-v21) =(1/2)×1.2((150)2-(100)2) =(1/2)×1.2(22500-10000) =7500 Nm-2

Q. Air of density $1.2 k g m^{- 3}$ is blowing across the horizontal wings of an aeroplane in such a way that its speeds above and below the wings are $150 m s^{- 1}$ and $100 m s^{- 1}$ , respectively. The pressure difference between the upper and lower sides of the wings, is :

$60 N m^{- 2}$

$180 N m^{- 2}$

$7500 N m^{- 2}$

$12500 N m^{- 2}$

Pressure difference
$P_{2} - P +_{1} = \frac{1}{2} ρ (v_{2}^{2} - v_{1}^{2})$
$= \frac{1}{2} \times 1.2 ((150)^{2} - (100)^{2})$
$= \frac{1}{2} \times 1.2 (22500 - 10000)$
$= 7500 N m^{- 2}$

Q. Air of density 1.2kgm−3 is blowing across the horizontal wings of an aeroplane in such a way that its speeds above and below the wings are 150ms−1 and 100ms−1, respectively. The pressure difference between the upper and lower sides of the wings, is :

60Nm−2

180Nm−2

7500Nm−2

12500Nm−2