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

$A$ 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

What is thrust?

Three identical vessels are filled with three liquids $A, B$,and $C$ with equal masses but having densities $\rho_A, \rho_B$,and $\rho_C$ respectively. If $\rho_A > \rho_B > \rho_C$,then the pressure at the bottom of the vessels will be:

$A$ vessel with a square cross-section and a height of $6 \ m$ is vertically partitioned. $A$ small window of $100 \ cm^2$ with a hinged door is fitted at a depth of $3 \ m$ in the partition wall. One part of the vessel is filled completely with water and the other side is filled with a liquid having a density of $1.5 \times 10^3 \ kg/m^3$. What force needs to be applied on the hinged door so that it does not open (in $N$)? (Acceleration due to gravity $= 10 \ m/s^2$)

An open-ended $U$-tube of uniform cross-sectional area contains water (density $1.0 \text{ g/cm}^3$) standing initially $20 \text{ cm}$ from the bottom in each arm. An immiscible liquid of density $4.0 \text{ g/cm}^3$ is added to one arm until a layer $5 \text{ cm}$ high forms,as shown in the figure. What is the ratio $h_2/h_1$ of the heights of the liquid in the two arms?