If the velocity of flow is $4 \, m/s$,then the velocity head is ......... $m$.

Consider the following equation of Bernoulli's theorem: $P + \frac{1}{2}\rho V^2 + \rho gh = K$ (constant). The dimensions of $K/P$ are the same as those of which of the following?

Explain the upward force (dynamic lift) acting on an airplane wing.

Air is blowing across the horizontal wings of an aeroplane in such a way that its speeds below and above the wings are $90\, m/s$ and $120\, m/s$ respectively. If the density of air is $1.3\, kg/m^3$,then the pressure difference between the lower and upper sides of the wings will be ........ $N/m^2$.

Water flows in a horizontal tube as shown in the figure. The pressure of water changes by $600\, N/m^2$ between $A$ and $B$ where the cross-sectional areas are $30\, cm^2$ and $15\, cm^2$ respectively. Find the rate of flow of water through the tube.

Explain why the roof of a building flies off during a stormy wind.