An aircraft of mass $3 \times 10^5 \ kg$ with total wing area $400 \ m^2$ is in a level flight at a speed of $540 \ km \ h^{-1}$. The density of air at its height is $1.2 \ kg \ m^{-3}$. The fractional increase in the speed of the air on the upper surface of its wings relative to the lower surface is . . . . . . $\left(g=10 \ ms^{-2}\right)$

$A$ liquid enters at point $A_{1}$ with a speed of $3.5 \ m/s$ and leaves at point $A_{2}$. Find the height attained by the liquid above point $A_{2}$ (in $cm$). (in $.25$)

$A$ bottle has a thin nozzle on top. It is filled with water,held horizontally at a height of $1 \,m$ and squeezed slowly by hands,so that the water jet coming out of the nozzle hits the ground at a distance of $2 \,m$. If the area over which the hands squeeze it is $10 \,cm^{2}$,the force applied by hand is close to .......... $N$ (take $g=10 \,m/s^{2}$ and density of water $=1000 \,kg/m^{3}$).

$A$ fully loaded Boeing aircraft has a mass of $3.3 \times 10^{5} \; kg$. Its total wing area is $500 \; m^{2}$. It is in level flight with a speed of $960 \; km/h$.
$(a)$ Estimate the pressure difference between the lower and upper surfaces of the wings.
$(b)$ Estimate the fractional increase in the speed of the air on the upper surface of the wing relative to the lower surface. [The density of air is $\rho = 1.2 \; kg/m^{3}$]

What is an aerofoil? Explain.

Water is flowing through a horizontal pipe of non-uniform cross-section. At the extreme narrow portion of the pipe, the water will have