The figure below shows a liquid being pushed out of a tube by a piston having a cross-sectional area of $2.0\,cm^2$. The cross-sectional area at the outlet is $10\,mm^2$. If the piston is pushed at a speed of $4\,cm/s$,the speed of the outgoing fluid is $.........\,cm/s$.

The surface of water in a water tank of cross-sectional area $750 \,cm^2$ on the top of a house is '$h$' $m$ above the tap level. The speed of water coming out through the tap of cross-sectional area $500 \,mm^2$ is $30 \,cm/s$. At that instant, $\frac{dh}{dt}$ is $x \times 10^{-3} \,m/s$. The value of '$x$' will be:

Two water pipes $P$ and $Q$ having diameters $2 \times 10^{-2} \, m$ and $4 \times 10^{-2} \, m$ respectively are joined in series with the main supply line of water. The velocity of water flowing in pipe $P$ is ........

$A$ 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 ..........

$A$ 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 $v$,what is the speed of water leaving the second pipe?

Two water pipes of diameters $2 \text{ cm}$ and $4 \text{ cm}$ are connected with the main supply line. The velocity of flow of water in the pipe of $2 \text{ cm}$ diameter is