By dividing the weight of a body by its volume, we obtain the specific weight, which is expressed in newtons per cubic meter. The relationship between the weight of a body and its volume is important in determining how light or heavy different materials are.
In mathematical language, specific gravity is a vector quantity, since it includes an equally vector factor, the effect of gravity. The action of gravity subjected to a unit of volume in a body determines its specific weight. It is very useful in all types of sectors, especially in those in which it is important to specify the ideal conditions to process a substance.
It is also used in mechanical engineering, in the field of fluids or in soils.
Density and specific weight
The density of an object or substance is obtained by dividing the mass by a unit of volume, which is expressed in kilograms per cubic meter. The density of a body determines its behavior in the aquatic environment, as stated in Archimedes' principle (a body immersed in a fluid experiences an upward thrust that is equal to the weight of the fluid it displaces). According to this principle, bodies that are floating have a density lower than that of liquid, while bodies that are submerged have a density greater than that of liquid.
The density of a body expresses the relationship between the mass of a body and the volume it occupies. As a general criterion, the density of a substance is variable, as it depends on changes in pressure and temperature.
Specific gravity and density are related, since both concepts share the variable of the volume of a body. In other words, the specific gravity is equal to the density multiplied by the action of gravity.
In a figurative sense
The language of physics and chemistry is sometimes extrapolated to ordinary language. It is worth remembering that the concepts of force, mass, pressure or acceleration have a mathematical definition and, at the same time, a certain use in everyday communication.
In this way, if an individual exerts a great influence in an organization or in a group of friends, it can be said of him that he has a great specific weight. Likewise, certain data or arguments are so important that when it comes to underlining their relevance, they talk about their specific weight.
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