Question

Round your answer to three significant figures.

Use Bernoulli's equation to estimate the upward force on an airplane's wing if the average flow of speed of air is 191 m/s above the wing and 164 m/s below the wing. The density of the air is 1.18 kgm^2 and the area of each wing surface is 25.0 m^2. Answer ___ N

Answer 1

Answer:-

A/c to Bernoulli's eqn:
p’/ρg + v’²/2g + z' = p/ρg + v²/2g + z,

with, z' = z = 0, v = 191 m/s, v' = 164 m/s, ρ = 1.18 kg/m³

p’ – p = ½ ρ(v² - v’²) = ½ 1.18 (191² - 164²) = 0.5 * 1.18* 9585 = 5655.15

The net force is the lift force and is given by the product pressure differential and the wing area.

F(net) = (p’ – p)A = 5655.15 (25) = 141378.75 N

Note: the pressure above the wing is lower and the air speed here is higher, while the pressure below the wing is higher and the airspeed there is lower.