What is a venturi meter?

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 . . . . . . $\left(g=10 \ ms^{-2}\right)$

Explain blood flow and heart attack with the help of Bernoulli's principle.

Pressure head in Bernoulli's equation is

The figure shows a liquid of given density flowing steadily in a horizontal tube of varying cross-section. The cross-sectional areas at $A$ is $1.5 \, cm^2$,and at $B$ is $25 \, mm^2$. If the speed of the liquid at $B$ is $60 \, cm/s$,then find $(P_A - P_B)$ in $Pa$. (Given: $P_A$ and $P_B$ are liquid pressures at points $A$ and $B$ respectively. Density $\rho = 1000 \, kg/m^3$. $A$ and $B$ are on the axis of the tube.)

$A$ train with cross-sectional area $S_t$ is moving with speed $v_t$ inside a long tunnel of cross-sectional area $S_0$ $(S_0 = 4S_t)$. Assume that almost all the air (density $\rho$) in front of the train flows back between its sides and the walls of the tunnel. Also,the air flow with respect to the train is steady and laminar. Take the ambient pressure and that inside the train to be $p_0$. If the pressure in the region between the sides of the train and the tunnel walls is $p$,then $p_0 - p = \frac{7}{2N} \rho v_t^2$. The value of $N$ is. . . . .