The pressure of confined air is $p$. If the atmospheric pressure is $P$,then

Why is walking barefooted on a sharp gravel (grit) road difficult?

Three liquids of equal masses are taken in three identical cubical vessels $A$,$B$,and $C$. Their densities are $\rho_{A}$,$\rho_{B}$,and $\rho_{C}$ respectively,where $\rho_{A} < \rho_{B} < \rho_{C}$. The force exerted by the liquid on the base of the cubical vessel is

The density changes with pressure for which fluid? Give reason.

There is a circular tube in a vertical plane. Two liquids which do not mix and of densities $d_1$ and $d_2$ are filled in the tube. Each liquid subtends a $90^o$ angle at the centre. The radius joining their interface makes an angle $\alpha$ with the vertical. The ratio $\frac{d_1}{d_2}$ is

The figure shows a container filled with a liquid of density $\rho$. Four points $A, B, C$ and $D$ lie on the diametrically opposite points of a circle as shown. Points $A$ and $C$ lie on a vertical line,and points $B$ and $D$ lie on a horizontal line. Which of the following statements is incorrect? (Here,$p_A, p_B, p_C, p_D$ are the absolute pressures at the respective points.)