If H is the depth of water retained by a vertical wall, the height of centre of pressure above the bottom is

ANS:A -

Traingle =H/2.
Rectangular=H/3.
Consider a rectangular plate of width b and height h is immersed in water.

h'= Depth of centre of gravity of rectangular plate from free surface = h/2.

Area = bh Moment of inertia through centre of gravity. IG = bh3/12.

h* = Distance of centre of pressure from the free surface of a liquid =( igsin^2@/ah')+h'

For vertical plane surface: θ = 90°

The distance of the centre of pressure from the base = h - 2h/3 = h/3.