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.

Why does a flag (or ensign) flutter when there is strong wind? Explain.

$A$ tank of height $15 \ m$ and cross-section area $10 \ m^2$ is filled with water. There is a small hole of cross-section area $a$ which is much smaller than the container,located at a height of $12 \ m$ from the base of the container. How much force should be applied with a piston at the top level,so that the water coming out of the hole hits the ground at a distance of $16 \ m$ (in $kN$)? (Take,density of water $\rho = 1000 \ kg \ m^{-3}$ and $g = 10 \ m/s^2$)

The speeds of air above and below the wing of an airplane are $120\, m/s$ and $90\, m/s$,respectively. The density of air is $1.3\, kg/m^3$. If the wing has a length of $10\, m$ and a width of $2\, m$,the pressure difference between the top and bottom of the wing is ......... $Pascal$.

Write the limitations of Bernoulli's equation.

Which of the following is not an assumption for an ideal fluid flow for which Bernoulli's principle is valid?