please solve question 15

t a k e a d x w i d t h r i n g a t d e p t h x p r e s s u r e a t t h i s p o i n t b e = ρ g h u p w a r d f o r c e d F = ρ g h (2 πx) . d x . \cos θ t h e t a i s c o n e a n g l e \cos θ = \frac{h}{\sqrt{h^{2} + R^{2}}} \ F = \int_{0}^{h} ρ g h (2 πx) \frac{h}{\sqrt{h^{2} + R^{2}}} . d x = \frac{2 π ρ g h^{2}}{\sqrt{h^{2} + R^{2}}} (\frac{h^{2}}{2}) = \frac{π ρ g h^{4}}{\sqrt{h^{2} + R^{2}}} u p w a r d f o r c e R e g a r d s