The speeds of air above and below the wing of an airplane are $120\, m/s$ and $90\, m/s$,respectively. The density of air is $1.3\, kg/m^3$. If the wing has a length of $10\, m$ and a width of $2\, m$,the pressure difference between the top and bottom of the wing is ......... $Pascal$.

Air streams horizontally past an airplane. The speed over the top surface is $60 \, m/s$ and that under the bottom surface is $45 \, m/s$. The density of air is $1.293 \, kg/m^3$. The difference in pressure is ....... $N/m^2$.

Why do two rowing boats moving parallel to each other come closer (attract) to each other?

The figure shows a siphon. Choose the wrong statement:
($P_0$ = atmospheric pressure)

$A$ 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 $=1000 \,kg/m^{3}$).

The flow speeds of air on the lower and upper surfaces of the wing of an aeroplane are $v$ and $2v$ respectively. The density of air is $\rho$ and the surface area of the wing is $A$. The dynamic lift on the wing is: