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Vertical Downward Pressure

المؤلف:  GEORGE A. HOADLEY

المصدر:  ESSENTIALS OF PHYSICS

الجزء والصفحة:  p-132

2025-11-08

443

When a liquid is contained in a vessel with vertical sides, the weight of each layer is transmitted undiminished to the layers below. Hence each layer bears the weight of the liquid above it, and the pressure on the bottom will be the weight of the liquid in the vessel.

Demonstration. - Screw one of the glass vessels shown in Fig. 1, into the ring of the standard. By fixing the index at any height and bringing the water to the height indicated, the pressure on the flexible base will be shown by the position of the pointer on lowering the water supply the water will run out of the glass vessel. Substitute a vessel of another shape. When the water surface is raised again to the fixed index, the pointer will read the same as before.

The above demonstration proves that the pressure on the bottom of a vessel containing a liquid is entirely independent of the shape of the vessel; with a given liquid it depends only upon the depth of the liquid and the area of the base.

Demonstration. - Use salt water, which is heavier than fresh and it will be found to require less height for the same pressure. From this we see that the pressure on the bottom of a vessel depends also upon the density of the liquid.