$A$ cylinder containing water up to a height of $25 \ cm$ has a hole of cross-section $\frac{1}{4} \ cm^2$ in its bottom. It is counterpoised in a balance. What is the initial change in the balancing weight when water begins to flow out?

State Torricelli's law.

Two large,identical water tanks,$1$ and $2$,kept on the top of a building of height $H$,are filled with water up to height $h$ in each tank. Both the tanks contain an identical hole of small radius on their sides,close to their bottom. $A$ pipe of the same internal radius as that of the hole is connected to tank $2$,and the pipe ends at the ground level. When the water flows out of tanks $1$ and $2$ through the holes,the times taken to empty the tanks are $t_1$ and $t_2$,respectively. If $H = (16/9) h$,then the ratio $t_1 / t_2$ is:

$A$ cylindrical vessel of $90 \ cm$ height is kept filled up to the brim. It has four holes $1, 2, 3, 4$ which are respectively at heights of $20 \ cm, 30 \ cm, 45 \ cm,$ and $50 \ cm$ from the horizontal floor $PQ.$ The water falling at the maximum horizontal distance from the vessel comes from:

$A$ tank with a small hole at the bottom has been filled with water and kerosene (specific gravity $0.8$). The height of water is $3\,m$ and that of kerosene $2\,m$. When the hole is opened,the velocity of fluid coming out from it is nearly ........ $ms^{-1}$. (Take $g = 10\,ms^{-2}$ and density of water $= 10^3\,kg\,m^{-3}$)

$A$ vertical tank,open at the top,is filled with a liquid and rests on a smooth horizontal surface. $A$ small hole is opened at the centre of one side of the tank. The area of cross-section of the tank is $N$ times the area of the hole,where $N$ is a large number. Neglect the mass of the tank itself. The initial acceleration of the tank is: