If water is flowing in a pipe with speed $2 \, m/s$,then its kinetic energy per unit volume is ........... $J/m^3$.

$A$ 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. . . . .

$A$ steady flow of a liquid of density $\rho$ is shown in the figure. At point $1$,the area of cross-section is $2A$ and the speed of flow of liquid is $\sqrt{2} \ m \ s^{-1}$. At point $2$,the area of cross-section is $A$. Between the points $1$ and $2$,the pressure difference is $100 \ N \ m^{-2}$ and the height difference is $10 \ cm$. The value of $\rho$ is (Acceleration due to gravity $= 10 \ m \ s^{-2}$) (in $kg \ m^{-3}$)

Write the limitations of Bernoulli's equation.

The reading of a pressure meter attached to a closed pipe is $4.5 \times 10^4 \ N/m^2$. On opening the valve,water starts flowing and the reading of the pressure meter falls to $2.0 \times 10^4 \ N/m^2$. The velocity of water is found to be $\sqrt{V} \ m/s$. The value of $V$ is . . . . . .

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.