Which statements concerning hydrostatic force on plane surfaces are correct?

Select all that apply

• Option A

  For a vertical plane area, the resultant hydrostatic force is ρgA h̄, where h̄ is the depth of its centroid.

• Option B

  For a vertical submerged plane surface, the centre of pressure is generally below the centroid.

• Option C

  On a horizontal plane surface at one depth in a static liquid, pressure is uniform and the resultant passes through the centroid.

• Option D

  For a vertical rectangle of width b and depth h with its upper edge at the free surface, the torque about the upper edge is ρgbh³/3.