Question

As depth of immersion of a vertical plane surface increases, the location of centre of pressure

• A. comes closer to the centre of gravity of the area
• B. moves apart from the centre of gravity of the area
• C. ultimately coincides with the centre of gravity of the area
• D. remains unaffected

Answer 1

The correct option is A comes closer to the centre of gravity of the area

The centre of pressure from free surface is
$h_p=h_c+\frac{I_G}{A{h}_c}$
where
$h_c\text{is depth of centroid from free surface}$
$I_G\text{is moment of inertia of vertical plane about horizontal centroidal axis}$
A is area of the plane
As depth of immersion increases, $h_c$ increases and therefore $\frac{I_G}{A{h}_c}$ decreases. It means that centre of pressure comes closer to centroid.