$A$ river gradually deepens from a depth of $4 \ m$ to a depth of $8 \ m$ as shown. The width,$W$,of the river does not change. At the depth of $4 \ m$,the river's speed is $12 \ m/s$. Its velocity at the $8 \ m$ depth is ......... $m/s$.

$A$ pipe having an internal diameter $D$ is connected to another pipe of the same size. Water flows into the second pipe through $n$ holes,each of diameter $d$. If the water in the first pipe has speed $v$,the speed of water leaving the second pipe is

In the figure shown,a liquid is flowing through a tube at the rate of $0.1\, m^3/sec$. The tube is branched into two semicircular tubes of cross-sectional area $A/3$ and $2A/3$. The velocity of liquid at $Q$ is ......... $m/sec$. (The cross-section of the main tube $= A = 10^{-2}\, m^2$ and $v_p = 20\, m/sec$)

Explain steady flow.

$A$ liquid flows in the tube from left to right as shown in the figure. $A_1$ and $A_2$ are the cross-sections of the portions of the tube as shown. The ratio of speed $\frac{v_1}{v_2}$ will be ..........

Fountains usually seen in gardens are generated by a wide pipe with an enclosure at one end having many small holes. Consider one such fountain which is produced by a pipe of internal diameter $2 \ cm$ in which water flows at a rate $3 \ ms^{-1}$. The enclosure has $100$ holes each of diameter $0.05 \ cm$. The velocity of water coming out of the holes is (in $ms^{-1}$):