$A$ liquid of mass $1 \ kg$ is filled in a flask as shown in the figure. The force exerted by the flask on the liquid is $(g = 10 \ m/s^2)$ [Neglect atmospheric pressure]:

Straws are used to take soft drinks. Why?

Two liquids of densities $\rho_{1}$ and $\rho_{2}$ (where $\rho_{2} = 2\rho_{1}$) are filled behind a vertical wall of height $10 \; m$ and width $w$,as shown in the figure. Each liquid has a height of $h = 5 \; m$. The ratio of the force exerted by the upper liquid on the part $MN$ to the force exerted by the lower liquid on the part $NO$ is (Assume that the liquids do not mix):

Two stretched membranes of area $2\, cm^2$ and $3\, cm^2$ are placed in a liquid at the same depth. The ratio of pressures on them is

The limbs of a $U$-tube are lowered into vessels $A$ and $B$,where vessel $A$ contains water. Some air is pumped out through the top of the tube at $C$. The liquids in the left limb (in vessel $A$) and the right limb (in vessel $B$) rise to heights of $10\, cm$ and $12\, cm$ respectively above the free surfaces of the liquids in the vessels. The density of liquid $B$ is ........ $g/cm^3$.

What is atmospheric pressure?