$A$ steady flow of water passes along a horizontal tube from a wide section $X$ to the narrower section $Y$,see figure. Manometers are placed at $P$ and $Q$ at the sections. Which of the statements $A, B, C, D$ is most correct?

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.

Two light balls are suspended as shown in the figure. When a stream of air passes through the space between them,the distance between the balls will

Which types of energies are present in the streamline flow of an ideal fluid?

The pans of a physical balance are in equilibrium. Air is blown under the right hand pan; then the right hand pan will

$A$ 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. . . . .