Archimedes force — the pushing-out force operating on a body which is shipped in liquid or gas in whole or in part is always directed vertically up and reduces the body weight of a body. It is very simple to calculate it — to calculate the weight of the liquid which is forced out by a body enough. It is equal to a vertical component of Archimedes force.
It is required to you
- sheet of paper;
- handle;
- ruler or roulette;
- vessel with water;
- thread.
Instruction
1. Buoyancy force arises because of the difference of pressure of water at the level of the top and lower cuts of a body. On the top part presses a water column h1 height with a force equal to the weight of this column. The lower part is affected by force equal to column weight with h2 height. This height is defined by addition h1 and height of the body. According to the law of Pascal, pressure in liquid or gas is distributed evenly extensively. Including up. It is obvious that force operating up exceeds force operating down. But, it is necessary to consider that only influence of a column of liquid is taken into account. The pushing-out force does not depend on the body weight of a body. Material of which the body is made its other qualities, except the sizes at calculations are not used. Calculation of buoyancy force is based only on density of liquid and the geometrical sizes of the shipped part.
2. There are two ways how to calculate the buoyancy force operating on the body shipped in liquid. The first consists in measurement of volume of a body and calculation of weight of the liquid occupying similar volume. For this purpose it is necessary that the body possessed the correct geometrical form, that is, was a cube, a parallelepiped, a sphere, a hemisphere, a cone. To calculate the volume of a solid body of more irregular shape very difficult therefore for determination of Archimedes force in this case there is more practical way No. 2. But about it a bit later. Having determined the volume of the immersed body, we multiply it by density of liquid and we find the size of the pushing-out force operating on this body in a homogeneous environment of the set density and on the acceleration of gravity of g (9.8 m / с2). The formula for determination of Archimedes force looks so: F=ρgVρ is the specific density of liquid; g - acceleration of gravity; V - the volume of the forced-out liquid. As well as any force, it is measured in Newtons (N).
3. The second way is based on measurement of volume of the forced-out liquid. It most corresponds to that experience which led Archimedes to opening of the law. This way is very convenient also at calculation of buoyancy force at partial immersion of a body. For obtaining necessary data the studied body is suspended on a thread and slowly lowered in liquid. It is enough to measure liquid level in a vessel before immersion of a body and later, to increase a difference of levels by surface area and to find the volume of the forced-out liquid. As well as in the first case, we multiply this volume by density of liquid and g. The received size is also Archimedes force. That Newton became unit of measure of force, it is necessary to measure volume in m3, and density — in kg/m3.