In this figure,an ideal liquid flows through a tube of uniform cross-section. The liquid has velocities $v_A$ and $v_B$,and pressures $P_A$ and $P_B$ at points $A$ and $B$ respectively.

Application of Bernoulli's theorem can be seen in

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 ........ $N/m^2$.

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

$A$ fully loaded Boeing aircraft has a mass of $3.3 \times 10^5 \text{ kg}$. Its total wing area is $500 \text{ m}^2$. It is in level flight with a speed of $960 \text{ km/h}$. Estimate the pressure difference between the lower and upper surfaces of the wings.

An ideal liquid flows through a horizontal tube of variable diameter. The pressure is lowest where the . . . . . . .