Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Correcting R. Lu's Example

I am not reviewing this book, I am correcting the previous review which is fundamentally wrong. The example used by R. Lu to demonstrate the typical errors in this text is correct - R. Lu is wrong.Force on a submerged surface is calculated using the centroid, or center of mass - indicated as hc. This is located at the midpoint of the surface (or h/2), in this particular case at a height of 0.75 meters.The location that the resultant force is applied on that surface is the center of pressure, which for a surface that is located in the free surface, may be calculated as h/3.The centroid (center of mass) and location of applied force (center of pressure) are not the same. R. Lu should review basic fluid mechanics before making foolish and incorrect statements.