تسجيل الدخول

تسجيل

Center of Pressure

المؤلف:  GEORGE A. HOADLEY

المصدر:  ESSENTIALS OF PHYSICS

الجزء والصفحة:  p-135

2025-11-09

693

The center of pressure on a submerged surface is the point of application of the resultant of all the forces acting upon it, due to the pressure of the liquid. If we have a rectangular side to a vessel containing water, since the pressure increases from the top to the bottom, it is evident that this point must be below the middle of the side. Calculation and experiment show that it is two thirds of the distance from top to bottom.

 A convenient way to determine the position of this point is as follows. Lay off a line CB (Fig. 1) perpendicular to the side AB  to represent the pressure at B. Draw the line CA. Any lines, as ED and GF, drawn perpendicular to AB, will represent the pressure at the points D and F respectively. Why?

The area of the triangle ABC will represent the entire pressure upon AB, and the center of pressure will be at the point H where the perpendicular from the center of area of the triangle meets the side AB. It is evident that this point will be in such a position that AH =2/3 AB, since the center of gravity of ABC is at O, a point such that AO = 2/3AK.  If the side AB is movable, a support at H will prevent either the top'or' the bottom from being pushed out.