$A$ jet of water with a cross-section of $6 \ cm^2$ strikes a wall at an angle of $60^{\circ}$ to the normal and rebounds elastically from the wall without losing energy. If the velocity of the water in the jet is $12 \ m/s$,the force acting on the wall is ....... $N$.

Mercury is filled in a tube of radius $2 \,cm$ up to a height of $30 \,cm$. The force exerted by mercury on the bottom of the tube is . . . . . . $N$.
(Given: atmospheric pressure $P_0 = 10^5 \,N/m^2$,density of mercury $\rho = 1.36 \times 10^4 \,kg/m^3$,$g = 10 \,m/s^2$,$\pi = \frac{22}{7}$)

Water is flowing at a speed of $1.5\, ms^{-1}$ through a horizontal tube of cross-sectional area $10^{-2}\, m^2$ and you are trying to stop the flow by your palm. Assuming that the water stops immediately after hitting the palm,the minimum force that you must exert should be ......... $N$ (density of water $= 10^3\, kgm^{-3}$)

$A$ stream of water flowing horizontally with a speed of $15\; m s^{-1}$ gushes out of a tube of cross-sectional area $10^{-2}\; m^2$,and hits a vertical wall nearby. What is the force in $N$ exerted on the wall by the impact of water,assuming it does not rebound?

Some liquid is filled in a cylindrical vessel of radius $R$. Let $F_1$ be the force applied by the liquid on the bottom of the cylinder. Now the same liquid is poured into a vessel of uniform square cross-section of side $R$. Let $F_2$ be the force applied by the liquid on the bottom of this new vessel. Then:

$A$ pressure-pump has a horizontal tube of cross-sectional area $10 \, cm^{2}$ for the outflow of water at a speed of $20 \, m/s$. The force exerted on the vertical wall just in front of the tube,which stops the water horizontally flowing out of the tube,is $... N$ [Given: density of water $= 1000 \, kg/m^{3}$].