Question

A circular plate 1 m in diameter is submerged vertically in water such that its upper edge is 8 m below the free surface of water. The total hydrostatic pressure force on one side of plate is

• A. 6.7 kN
• B. 65.4 kN
• C. 45.0 kN
• D. 77.0 kN

Answer 1

The correct option is B 65.4 kN

Given data:
d = 1 m
$\overline{h}=8+\frac{d}{2}=8+\frac{1}{2}=8.5m$


Surface area,
$A=\frac{\pi }{4}{d}^2=\frac{3.14}{4}\times 1^2=0.785m^2$

Total hydrostatic pressure force,
$F=\rho g\overline{h}A=1000\times 9.81\times 8.5\times 0.785$
=65457.22 N $\simeq 65.45kN$