$A$ square gate of size $1\,m \times 1\,m$ is hinged at its mid-point. $A$ fluid of density $\rho$ fills the space to the left of the gate. The force $F$ required to hold the gate stationary is

$A$ siphon in use is demonstrated in the following figure. The density of the liquid flowing in the siphon is $1.5 \text{ g/cm}^3$. The pressure difference between the points $P$ and $S$ will be

What is absolute pressure? And what is gauge pressure?

Three identical vessels are filled with equal masses of three different liquids $A, B$ and $C$ $(\rho_A > \rho_B > \rho_C)$. The pressure at the base will be

Why is the dam of a water reservoir thick at the bottom?

At a depth of $1000 \; m$ in an ocean:
$(a)$ What is the absolute pressure?
$(b)$ What is the gauge pressure?
$(c)$ Find the force acting on the window of area $20 \; cm \times 20 \; cm$ of a submarine at this depth,the interior of which is maintained at sea-level atmospheric pressure. (The density of sea water is $1.03 \times 10^3 \; kg \; m^{-3}$,$g = 10 \; m \; s^{-2}$.)