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Pressure is transmitted uniformly throughout the liquid

In conse­quence of Pascal’s principle, whatever pres­sure is communicated to the liquid by the pump is transmitted undiminished to the walls of the containing cylinder and the piston C. If the large piston С has 100 times the area of the small piston D, the force exerted on С will be 100 times that applied to D, and on the downward stroke of the small piston the large piston С will be moved only one hundredth the distance through which the small piston moved. If the oil is incompressible, the work done on the large piston is just equal to that done on the small piston, i.e., the input of the machine is just equal to the output. In order to increase the pressure exerted on the piston C still further, the small piston is ordinarily forced down by means of a lever. Hydraulic presses are used in baling paper, cotton, etc., in punching holes through steel plates, and extracting oil from seeds. By means of them, a small force operat­ing through a large distance produces a large force operating through a small distance [2, С. 77 - 79].

True or false?

1. The shape of the containing vessel depends on the kind of the liquid and its shape.

2. Liquids always resist changing their volume.

3. To find the pressure on the bottom of the vessel with ver­tical sides we should multiply height of the liquid by its density.

4. The depth below free surface determines the pressure in a liquid.

5. The heights of two liquids above their surface of separation are proportional to the densities of the liquids.

6. The relation of heightsof the liquids in communicating tubes is proportional to the relation of their densities.

7. The check valve in a hydraulic press is used to pump oil into the large cylinder.

8. Thanks to the fact that hydraulic presses help to convert a large force into a small one they are widely used for extracting oil from seeds.

2.10.2 Read the text, translate it and name the main points of the Archimedes’ Principle. Finish the following statement:

A body immersed in a fluid would dis­place the fluid of equal …

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