A fully loaded boeing aircraft has a mass of 5 . 4 × 10 ^ 5 kg ....

Required lift force, $F = {P}_{2}A - {P}_{1}A = 5 . 4 \times {10}^{5} \times g$

$⇒ {P}_{2} - {P}_{1} = \dfrac{5 . 4 \times {10}^{6}}{500} = 5 . 4 \times 2 \times {10}^{3}$

$= 10 . 8 \times {10}^{3}$

Now applying Bernoulli's Theorem we get

${P}_{2} + 0 + \dfrac{1}{2}ρ{V}_{2}^{2} = {P}_{1} + 0 + \dfrac{1}{2}ρ{V}_{1}^{2}$

$⇒ {P}_{2} - {P}_{1} = \dfrac{1}{2}ρ\left({V}_{1}^{2} - {V}_{2}^{2}\right) = \dfrac{1}{2}ρ\left({V}_{1} - {V}_{2}\right)\left({V}_{1} + {V}_{2}\right)\left[\text{Since\text{ for } small change}, {V}_{1} = {V}_{2} = V = 1080km{h}^{- 1} = 300m{s}^{- 1}\right]$

$⇒ 10 . 8 \times {10}^{3} = \dfrac{1}{2} \times 1 . 2\left({V}_{1} - {V}_{2}\right) \times 2 \times 300$

$⇒ 10 . 8 \times 10 = 3 . 6\left({V}_{1} - {V}_{2}\right)$

$⇒ {V}_{1} - {V}_{2} = 30$

Therefore, fractional increase will be\left(\dfrac{{V}_{1} - {V}_{2}}{V}\right) \times 100 = \dfrac{30}{300} \times 100 = 10 %