It is presumed that the triangular plate ABC is submerged in water with base BC in level with the water surface as shown in the figure below. Consider an elementary rectangular strip of width ∆y at a distance y from the vertex A and length2x. Its depth from the surface would be -y. Line passing through A and perpendicular to BC be taken Y axis with origin at A

Weight of the water column over this element= ρ. g.(-y)2x ∆y, where ρ is the density

of the water and g is the gravity. This would constitute the hydrostatic force on the element. Since ρg= 9800 newton per cubic meter and x= ytan30, substituting for ρg and x, the force will be 19600(-y) ytan 30 ∆y. For total force on the plate, we have to integrate the expression with limits for y being 0 to .

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