probably no students who have never heard the following problem: "Which is easier - a kilo or a kilo bricks down?".The oddest thing was that, despite the verbal nonsense, many get involved in useless argument.When there was a share in the social practice - is unknown, but it can be assumed that the assessment of the weight data of surrounding objects by comparing their volume characteristics has been known since the time of Archimedes.Specific characteristics are understood as the attitude of some of the measured values, for example, weight and volume.Calculate the proportion of the ratio G:
G = P / V, as the unit of measurement in the SI - n / m cu.
Weight - a measure of Earth's gravity, and the proportion of the reason is not the physical characteristics of the substance, as it depends on the place of measurement.What follows?Let us remember that the weight of P - a power characteristic of the gravitational field, which is associated with the inertial characteristics of the substance mass m, through the gravitational acceleration g.On the other hand, g - vacillates and depends, including, and from geographical coordinates.Since Newton's first law P = m * g is just always, it is possible to conclude that the variability of weight at the same time with the change of gravitational acceleration.
classic definition is: "The share - is the ratio of body weight to its volume."However, this simplicity lies quite substantial difficulty - incorrect application of the units has led to confusion related to weight and body weight.As is known, system mass unit (SI) is equal to 1 kg, and the power in the system, according to Newton's law, it is measured in newtons, and 1H = 0.102 kg * 9.8 m / sec.sq.
For many technical applications unit of force newton more inconvenient, so even went on to create a new measurement system - MKGSS.It consisted of mixed units of measurement: meter - kgf - second.What gives?It simplifies the use of force units in real life by the same numerical expression of the specific weight and specific gravity, iedensity in different systems, provided that the acceleration g is a constant or negligible.
need to use the proportion of demand in the technologies of identification of materials, the determination of impurities in them or porous structure.
a well-known method for determining the sample of gold, the density structure of precious stones, etc.The main method of measuring the specific gravity based on various versions of repression: measured body weight and, by immersion in water, its volume, and the rest, as they say - a trick.Particularly effective is the use of data obtained in this way, in the study of metals and their alloys.Normally, a priori, known proportion of metal with a well-studied properties.Their identity to establish new models in many respects, but begin a study measuring the specific gravity.
The liquid used is usually water, and the measurements of high accuracy it provides high stability of the external parameters - temperature and pressure.Sometimes, for example, in the study of amber for forgery using special liquid with a specific gravity of more than 2 g / cc.
The share has become a major element in the implementation of technology in the commercial production of magnetic fluids.The fine suspension with kerosene ferroporoshkom allows a magnetic field to easily create a liquid with variable controls, or pre-assigned a specific weight.For such a process shoulder enrichment ores and many other materials with many impurities, which layers are separated by adjustment of the flotation bath in exact accordance with their individual specific gravity.It is possible that for such environmentally friendly technologies ore dressing - great future.
