An aquarium is filled with water. The lateral wall of the aquarium is $50 \mathrm{cm}$ long and $40 \mathrm{cm}$ high. Using $10 \mathrm{m} {\mathrm{s}}^{-2}$ for the acceleration due to gravity, and $1 \mathrm{g} {\mathrm{cm}}^{-3}$ for the density of water, the force on the lateral wall of the aquarium is

Reason: Pressure difference depends upon the curvature.

An incompressible, non-viscous liquid of density $\rho$ flows through a horizontal tube as shown below. The flow condition is steady. Area of the cross-section at $A$ and $B$ are $a_1$ and $a_2$ respectively. The height difference of liquid in two tubes inserted at $A$ and $B$ is $h$.