$1\mathrm{.}4$

$1\mathrm{.}4\mathrm{.}1$ The top of a vertical retaining wall in the form of a parabola $,6m$ wide and $4m$ deep, is $2m$ below the water's surface.

Sketch the wall and show the representative strip that you will use to calculate the area moment of the wall about the water level.

Calculate the relation between the two variables, $x$ and $y$

$1\mathrm{.}4\mathrm{.}2$ Caiculate, by using integration, the area moment of the retaining wall about the water level in QUESTION $1\mathrm{.}4\mathrm{.}1.$