A rectangular plate 2metre long and 15metre wide is immersed in water in the vertical position so that its top 15metre wide edge is parallel to and below the free water surface by 25metre Find total pressure and centre of pressure Let specific mass of water be 1000kg/m

Given data :

Width of rectangular plate = b = 1.5 m

Depth of rectangular plate = d = 2 m

Upper edge is parallel to and 2.5 m below water surface

Specific mass of the water = rho = 1000 Kg / m³

therefore, Area of rectangular plate = A = b × d = 1.5 × 2 = 3 m²

Also, h = 2.5 + 1 = 3.5 m

Total pressure = F = rho × g × h × A = 1000 × 9.81 × 3.5 × 3 = 103005 N

Centre of pressure = h* = ( Ig / A × h ) + h = ( 1 / 3 × 3.5 ) + 3.5 = 3.59 m

where, Ig = Moment of Inertia about the C. G. of the area of surface = bd³ / 12 = ( 1.5 × 2³ ) / 12 = 1 m