Determine their share in the total. Metals with the highest and lowest specific gravity. Specific gravity - main working
The concept of specific gravity is very often found in various fields of science and life. What does it mean and how to calculate the specific gravity?
Concept in physics
Specific gravity in physics is defined as the weight of a substance per unit volume. In the SI measurement system, this value is measured in N / m3. To understand how much 1 N / m3 is, it can be compared with a value of 0.102 kgf / m3.
where P is the body weight in Newtons; V is the volume of the body in cubic meters.
If we consider, for example, simple water, then we can see that its density and specific gravity are almost the same and change very slightly with changes in pressure or temperature. Her at. v. is equal to 1020 kgf / m3. The more salts are dissolved in the composition of this water, the greater the value of y. v. This indicator for sea water is much higher than for fresh water, and is equal to 1150 - 1300 kgf / m3.
The scientist Archimedes once noticed a long time ago that a buoyant force acts on a body immersed in water. This force is equal to the amount of fluid that the body has displaced. When the body weighs less than the volume of the displaced liquid, then it floats on the surface and goes to the bottom, if the situation is the opposite.
Specific gravity calculation
"How to calculate the specific gravity of metals?" - such a question often concerns those who develop heavy industry. This procedure is needed in order to find among the various variations of metals those that will differ in better quality characteristics.
The peculiarities of various alloys are as follows: depending on what metal is used, be it iron, aluminum or brass, of the same volume, the alloy will have a different mass. The density of a substance, calculated according to a certain formula, is most directly related to the question that workers ask when processing metals: "How to calculate the specific gravity?"
As mentioned above, y. v. is the ratio of body weight to its volume. Do not forget that this value is also defined as the force of gravity of the volume of the substance being determined taken as a basis. For metals, their y. v. and density are in the same ratio as weight to weight of the subject. Then you can use one more formula that will answer the question of how to calculate the specific gravity: u.v. / density = weight / mass = g, where g is a constant value. The unit of measure is y. v. metal is also N / m3.
Thus, we came to the conclusion that the specific gravity of a metal is called the weight per unit volume of a dense or non-porous material. To determine y. c., you need to divide the mass of dry material by its volume in an absolutely dense state - in fact, this is the formula used to determine the weight of the metal. To achieve this result, the metal is brought to such a state that no pores remain in its particles, and it has a homogeneous structure.
Share in the economy
The share in the economy is one of the most frequently discussed indicators. Calculate it to analyze the economic, financial part of the economic activity of the organization, etc. This is one of the main methods of statistical analysis, or rather, the relative magnitude of this structure.
Often, the concept of a share in an economy is a designation of a fraction of the total volume. The unit of measurement in this case is the percentage.
W. in. = (Part of the Whole / Whole) X100%.
As you can see, this is a well-known formula for finding the percentage between the whole and its part. This leads to the observance of 2 very important rules:
- The general structure of the phenomenon under consideration should in total be no more and no less than 100%.
- It does not matter at all what specific structure is being considered, whether it is the structure of assets or the proportion of personnel, the structure of the population or the proportion of costs, the calculation in any case will be carried out according to the above formula.
Specific gravity in medicine
The specific gravity in medicine is a fairly common concept. Use it for analyzes. It has long been known that u.v. water is proportional to the concentration of dissolved substances in it, the more there are, the greater the specific gravity. W.V. distilled water at 4 degrees Celsius equals 1,000. Hence it follows that u.v. urine can give an idea of the amount of substances dissolved in it. This or that diagnosis can also be made from here.
In order not to get confused, I will form a formula from your assignment, i.e.
It is necessary to find - the specific gravity
There are two meanings:
1 - some indicator
2 - general part
You need to find it as a percentage.
So the formula will look like this:
Specific gravity = some indicator / total part * 100%
There is a common part. It is taken for 100%. It consists of individual components. Their specific gravity can be calculated using the following template (formula):
Thus, the numerator will contain a part of the whole, and the denominator will contain the whole itself, and the fraction itself is multiplied by one hundred percent.
When finding the specific gravity, two important rules must be remembered, otherwise the decision will be wrong:
Examples of calculation in a simple and complex structure can be found at the link.
Let us consider the calculation of the specific weight as a percentage using the example of calculating the specific weight of the average number of employees, for ease of writing, this term will be defined by the abbreviation of the average number of employees.
The procedure for calculating the CER is provided for by the Tax Code of the Russian Federation, clause 1 of article 11.
To calculate the SDR for each individual division, head office and organization in full, you need to calculate the SDR for each month, then the SDR for the reporting period.
The amount of the NAR for each calendar day of the month, divided by the number of days of the month, will be equal to the ND for the month.
The amount of the NRA for each month of the reporting period, divided by the number of months of the reporting period, is equal to the NAR for the reporting period.
In accordance with clause 8-1.4 of the instructions of Rosstat, the SChR is indicated only in full units. For young, newly formed separate subdivisions, the value of the HR for the reporting period may be less than a whole number. Therefore, in order not to conflict with the tax authorities, for tax purposes, it was proposed to apply mathematical rules to the data when calculating the SDR, not to take into account less than 0.5, and round more than 0.5 to one.
The HRD value of a separate subdivision / parent organization, divided by the HRD value for the organization as a whole for the reporting period, will be equal to the indicator of the specific weight of the HRD of each separate subdivision and parent organization.
First, let's understand what the specific gravity of a component of a substance is. This is its ratio to the total mass of the substance, multiplied by 100%. It's simple. You know how much the whole substance (mixture, etc.) weighs, you know the weight of a particular ingredient, divide the weight of the ingredient by the total weight, multiply by 100% and get the answer. Also, the specific gravity can be estimated through specific gravity.
To assess the importance of a tog or other indicator, you need calculate specific gravity as a percentage... For example, in the budget, you need to calculate the proportion of each item in order to deal with the most important budget items first.
To calculate the specific weight of indicators, you need to divide the sum of each indicator by the total total of all indicators and multiply by 100, that is: (indicator / sum) x100. We get the weight of each indicator as a percentage.
For example: (255/844) x100 = 30.21%, that is, the weight of this indicator is 30.21%.
The sum of all specific gravities in the end should be equal to 100, so you can check the correctness of the calculation of the specific gravity in percent.
The specific gravity is calculated as a percentage. You find the share of the particular of the general, which, in turn, is taken as 100%.
Let's explain with an example. We have a fruit bag / bag that weighs 10 kg. The bag contains bananas, oranges and tangerines. The weight of bananas is 3 kg, the weight of oranges is 5 kg, and the weight of tangerines is 2 kg.
To determine specific gravity For example, for oranges, you need to take the weight of the oranges divided by the total weight of the fruit and multiply by 100%.
So, 5 kg / 10 kg and multiply by 100%. We get 50% - this is the specific gravity of oranges.
The unit weight is calculated as a percentage !! let's say a part of a whole. Means the part is divided by the whole number and multiplied by 100%.
Then 10002000 * 100% = 50. And so each specific gravity needs to be calculated.
To calculate the specific weight of some indicator as a percentage of the total part, you need to directly divide the value of this indicator by the value of the total part and multiply the resulting number by one hundred percent. This will give you the specific gravity as a percentage.
Specific gravity, as a physical indicator, is calculated by the formula:
Where P is the weight
and V is the volume.
The specific gravity as a percentage is calculated by a simple ratio Whole specific gravity to Parts of the specific gravity;. To get a percentage, you need to multiply the final result by 100:
Determination of specific gravity
The physical quantity, which is the ratio of the weight of the material to the volume it occupies, is called the HC of the material.
Materials science of the XXI century has gone far ahead in and already mastered technologies that were considered fiction some hundred years ago. This science can offer the modern industry alloys that differ from each other in quality parameters, but also in physical and technical properties.
To determine how a certain alloy can be used for production, it is advisable to determine the HC. All items made with the same volume, but different types of metals were used for their production, will have a different mass, it is in a clear connection with the volume. That is, the ratio of volume to mass is a certain constant number characteristic of this alloy.
To calculate the density of the material, a special formula is used, which has a direct connection with the HC of the material.
By the way, HC cast iron, the main material for creating steel alloys, can be determined by the weight of 1 cm 3, reflected in grams. The more metal HC, the heavier the finished product will be.
Specific gravity formula
The formula for calculating HC looks like the ratio of weight to volume. To calculate the HC, it is permissible to use the calculation algorithm, which is described in the school physics course.
For this it is necessary to use Archimedes' law, more precisely, the definition of the force, which is buoyant. That is, a load with a certain mass and at the same time it is kept on the water. In other words, it is influenced by two forces - gravity and Archimedes.
The formula for calculating the Archimedean force is as follows
where g is the fluid shock. After the substitution, the formula takes the following form F = y × V, from here we obtain the formula for the HC of the cargo y = F / V.
Difference between weight and mass
What is the difference between weight and mass. In fact, in everyday life, it does not play any role. In fact, in the kitchen, we do not make development between the weight of the chicken and its mass, but there are serious differences between these terms.
This difference is clearly visible when solving problems related to the movement of bodies in interstellar space and not as having a relationship with our planet, and under these conditions these terms differ significantly from each other.
We can say the following, the term weight has a meaning only in the area of action of gravity, i.e. if an object is near a planet, a star, etc. Weight can be called the force with which the body presses on the obstacle between it and the source of attraction. This force is measured in newtons. As an example, you can imagine the following picture - next to a paid education there is a plate with a certain object located on its surface. The force with which the object presses against the surface of the slab will be the weight.
Body mass is directly related to inertia. If we consider this concept in detail, then we can say that mass determines the size of the gravitational field created by the body. In fact, this is one of the key characteristics of the universe. The key difference between weight and mass is that mass is independent of the distance between an object and the source of gravitational force.
To measure mass, many quantities are used - kilogram, pound, etc. There is an international SI system, in which we use the usual kilograms, grams, etc. But besides it, in many countries, for example, the British Isles, there is their own system of measures and weights, where weight is measured in pounds.
UV - what is it?
Specific gravity is the ratio of the weight of matter to its volume. In the international system of measurements, SI, it is measured as a newton per cubic meter. To solve certain problems in physics, HC is defined as follows - how much heavier the substance under examination is than water at a temperature of 4 degrees, provided that the substance and water have equal volumes.
For the most part, this definition is used in geological and biological research. Sometimes the HC calculated by this method is called the relative density.
What are the differences
As already noted, these two terms are often confused, but since weight is directly dependent on the distance between the object and the gravitational source, and mass does not depend on this, therefore the terms shock and density are different.
But it is necessary to take into account the fact that under some conditions the mass and weight may be the same. It is almost impossible to measure HC at home. But even at the level of a school laboratory, such an operation is quite easy to perform. The main thing is that the laboratory is equipped with scales with deep bowls.
The item must be weighed under normal conditions. The resulting value can be designated as X1, after which the bowl with the load is placed in water. At the same time, in accordance with Archimedes' law, the cargo will lose part of its weight. In this case, the balance beam will tilt. To achieve balance, add a weight to the other pan. Its value can be designated as X2. As a result of these manipulations, an HC will be obtained, which will be expressed as the ratio of X1 and X2. In addition to the substance in the solid state, the specific can be measured for liquids and gases. In this case, measurements can be carried out in different conditions, for example, at elevated ambient temperatures or low temperatures. To obtain the required data, devices such as a pycnometer or a hydrometer are used.
Specific gravity units
In the world, several systems of measures and weights are used, in particular, in the SI system, HC is measured in the ratio of H (Newton) to a cubic meter. In other systems, for example, the CGS for specific gravity, such a unit of measurement is used d (dyne) to a cubic centimeter.
Metals with the highest and lowest specific gravity
In addition to the fact that the concept of specific gravity is used in mathematics and physics, there are quite interesting facts, for example, about the specific gravity of metals from the periodic table. if we talk about non-ferrous metals, then the most "heavy" include gold and platinum.
These materials exceed in specific gravity such metals as silver, lead and many others. The "light" materials include magnesium with a weight lower than that of vanadium. We must not forget about radioactive materials, for example, the weight of uranium is 19.05 grams per cubic cm. That is, 1 cubic meter weighs 19 tons.
Specific gravity of other materials
Our world is hard to imagine without many materials used in production and everyday life. For example, without iron and its compounds (steel alloys). The HC of these materials fluctuates in the range of one or two units, and these are not the best results. Aluminum, for example, has a low density and low specific gravity. These indicators made it possible to use it in the aviation and space industries.
Copper and its alloys have a specific gravity comparable to that of lead. But its compounds are brass, bronze is lighter than other materials, due to the fact that substances with a lower specific gravity are used in them.
How to calculate the specific gravity of metals
How to determine HC - this question often arises among specialists employed in heavy industry. This procedure is necessary in order to determine exactly those materials that will differ from each other with improved characteristics.
One of the key features of metal alloys is which metal is the base of the alloy. That is, iron, magnesium or brass having the same volume will have a different mass.
The density of the material, which is calculated on the basis of a given formula, is directly related to the issue in question. As already noted, HC is the ratio of body weight to its volume, it must be remembered that this value can be defined as the force of gravity and volume of a certain substance.
For metals, HC and density are determined in the same proportion. It is permissible to use one more formula that allows you to calculate the HC. It looks like this SW (density) is equal to the ratio of weight and mass, taking into account g, a constant value. We can say that the hydrocarbon of a metal can be called the weight of a unit of volume. In order to determine HC it is necessary to divide the dry material mass by its volume. In fact, this formula can be used to get the weight of the metal.
By the way, the concept of specific gravity is widely used in the creation of metal calculators used to calculate the parameters of rolled metal of various types and purposes.
The HC of metals is measured in qualified laboratories. In practical terms, this term is rarely used. Much more often, the concept of light and heavy metals is used, metals with a low specific gravity are classified as light, respectively, metals with a high specific gravity are classified as heavy.
Difference between weight and mass
To begin with, it is worth discussing the difference, which in everyday life is completely unimportant. But if you are solving physical problems about the motion of bodies in space that is not connected with the surface of the planet Earth, then the differences that we will cite are very significant. So, let's describe what is the difference between weight and mass.
Determination of weight
Weight makes sense only in the field of gravity, that is, near large objects. In other words, if a person is in the gravitational zone of a star, planet, large satellite or a decent-sized asteroid, then the weight is the force exerted by the body on the obstacle between him and the source of gravity in a stationary frame of reference. This value is measured in newtons. Imagine that there is a star hanging in space, at some distance from it there is a stone slab, and an iron ball lies on the slab. This is the force with which he presses on the obstacle, such will be the weight.
As you know, gravity depends on the distance and mass of the attracting object. That is, if the ball lies far from a heavy star or close to a small and relatively light planet, then it will act on the plate in the same way. But at different distances from the source of gravity, the resistance force of the same object will be different. What does it mean? If a person moves within the same city, then nothing. But if we are talking about a climber or a diver, then let him know: deep under the ocean, closer to the core, objects have more weight than at sea level, and high in the mountains - less. However, within our planet (by the way, not the largest, even in the solar system), the difference is not so significant. It becomes noticeable when going into outer space, outside the atmosphere.
Determination of mass
Mass is closely related to inertia. If you go deeper, then it determines what gravitational field the body creates. This physical quantity is one of the most fundamental characteristics. It depends only on matter at non-relativistic (that is, close to light) speeds. Unlike weight, mass does not depend on the distance to another object; it determines the strength of interaction with it.
Also, the value of the mass of the object is invariant to the system in which it is determined. It is measured in such quantities as a kilogram, a ton, a pound (not to be confused with a foot) and even a stone (which in English means "stone"). It all depends on what country a person lives in.
Determination of specific gravity
Now that the reader has figured out this important difference between two similar concepts and does not confuse them with each other, we will move on to what is specific gravity. This term denotes the ratio of the weight of a substance to its volume. In the universal SI system, it is designated as newton per cubic meter. Note that the definition refers to a substance that is mentioned either in a purely theoretical (usually chemical) aspect, or in relation to homogeneous bodies.
In some problems solved in specific areas of physical knowledge, the specific gravity is calculated as the following ratio: how much the substance under study is heavier than water of four degrees Celsius with equal volumes. As a rule, this approximate and relative value is used in sciences related, rather, to biology or geology. This conclusion is based on the fact that the indicated temperature is the average in the ocean for the planet. In another way, the specific gravity, determined by the second method, can be called the relative density.
Difference between specific gravity and density
The ratio that determines this value is easily confused with density, since it is mass divided by volume. However, weight, as we have already found out, depends on the distance to the source of gravity and its mass, and these concepts are different. It should be noted that under certain conditions, namely, at a low (nonrelativistic) speed, constant g, and small accelerations, density and specific gravity can numerically coincide. This means that by calculating two quantities, you can get the same value for them. When the above conditions are met, such a coincidence may lead to the idea that these two concepts are one and the same. This delusion is dangerous due to the fundamental difference between the properties laid down in their foundation.
Specific gravity measurement
At home, it is difficult to obtain the specific gravity of metals and other solids. However, in the simplest laboratory equipped with a balance with deep bowls, say, in a school, this will not be difficult. A metal object is weighed under normal conditions - that is, simply in air. We will register this value as x1. Then the bowl containing the object is immersed in water. At the same time, he loses weight according to the well-known Archimedes law. The device loses its original position, the rocker tilts. A weight is added for balancing. We denote its value by x2.
The specific gravity of the body will be the ratio of x1 to x2. In addition to metals, specific gravity is measured for substances in various states of aggregation, at unequal pressure, temperature, and other characteristics. To determine the desired value, methods of weighing, pycnometer, hydrometer are used. In each specific case, such experimental setups should be selected that take into account all factors.
Substances with the highest and lowest specific gravity
In addition to pure mathematical and physical theory, peculiar records are of interest. Here we will try to cite those elements of the chemical system that have the highest and lowest recorded specific gravity. Among the non-ferrous metals, the most "heavy" are the noble platinum and gold, followed by tantalum, named after the ancient Greek hero. The first two substances in terms of specific gravity are almost twice the similar values of the following silver, molybdenum and lead. Well, magnesium became the lightest among the noble metals, which is almost six times less than the slightly heavier vanadium.
Specific gravity values of some other substances
The world of our time would be impossible without iron and its various alloys, and their specific gravity undoubtedly depends on their composition. Its value varies within one or two units, but on average, these are not the highest rates among all substances. What can we say about aluminum? Like its density, its specific gravity is very low - only twice as much magnesium. This is a significant advantage for the construction of high-rise buildings, for example, or aircraft, especially when combined with properties such as strength and ductility.
But copper has a very high specific gravity, almost on a par with silver and lead. Moreover, its alloys, bronze and brass, are slightly lighter due to other metals having a lower value of the discussed value. A very beautiful and incredibly expensive diamond has rather a low specific gravity - only three times that of magnesium. Silicon and germanium, without which modern miniature gadgets would be impossible, despite the fact that they have similar structures, nevertheless differ. The specific gravity of the former is almost half that of the latter, although both are relatively light substances on this scale.
In order not to get confused, I will form a formula from your assignment, i.e.
It is necessary to find - the specific gravity
There are two meanings:
1 - some indicator
2 - general part
You need to find it as a percentage.
So the formula will look like this:
Specific gravity = some indicator / total part * 100%
There is a common part. It is taken for 100%. It consists of individual components. Their specific gravity can be calculated using the following template (formula):
Thus, the numerator will contain a part of the whole, and the denominator will contain the whole itself, and the fraction itself is multiplied by one hundred percent.
When finding the specific gravity, two important rules must be remembered, otherwise the decision will be wrong:
Examples of calculation in a simple and complex structure can be found at the link.
Let us consider the calculation of the specific weight as a percentage using the example of calculating the specific weight of the average number of employees, for ease of writing, this term will be defined by the abbreviation of the average number of employees.
The procedure for calculating the CER is provided for by the Tax Code of the Russian Federation, clause 1 of article 11.
To calculate the SDR for each individual division, head office and organization in full, you need to calculate the SDR for each month, then the SDR for the reporting period.
The amount of the NAR for each calendar day of the month, divided by the number of days of the month, will be equal to the ND for the month.
The amount of the NRA for each month of the reporting period, divided by the number of months of the reporting period, is equal to the NAR for the reporting period.
In accordance with clause 8-1.4 of the instructions of Rosstat, the SChR is indicated only in full units. For young, newly formed separate subdivisions, the value of the HR for the reporting period may be less than a whole number. Therefore, in order not to conflict with the tax authorities, for tax purposes, it was proposed to apply mathematical rules to the data when calculating the SDR, not to take into account less than 0.5, and round more than 0.5 to one.
The HRD value of a separate subdivision / parent organization, divided by the HRD value for the organization as a whole for the reporting period, will be equal to the indicator of the specific weight of the HRD of each separate subdivision and parent organization.
First, let's understand what the specific gravity of a component of a substance is. This is its ratio to the total mass of the substance, multiplied by 100%. It's simple. You know how much the whole substance (mixture, etc.) weighs, you know the weight of a particular ingredient, divide the weight of the ingredient by the total weight, multiply by 100% and get the answer. Also, the specific gravity can be estimated through specific gravity.
To assess the importance of a tog or other indicator, you need calculate specific gravity as a percentage... For example, in the budget, you need to calculate the proportion of each item in order to deal with the most important budget items first.
To calculate the specific weight of indicators, you need to divide the sum of each indicator by the total total of all indicators and multiply by 100, that is: (indicator / sum) x100. We get the weight of each indicator as a percentage.
For example: (255/844) x100 = 30.21%, that is, the weight of this indicator is 30.21%.
The sum of all specific gravities in the end should be equal to 100, so you can check the correctness of the calculation of the specific gravity in percent.
The specific gravity is calculated as a percentage. You find the share of the particular of the general, which, in turn, is taken as 100%.
Let's explain with an example. We have a fruit bag / bag that weighs 10 kg. The bag contains bananas, oranges and tangerines. The weight of bananas is 3 kg, the weight of oranges is 5 kg, and the weight of tangerines is 2 kg.
To determine specific gravity For example, for oranges, you need to take the weight of the oranges divided by the total weight of the fruit and multiply by 100%.
So, 5 kg / 10 kg and multiply by 100%. We get 50% - this is the specific gravity of oranges.
The unit weight is calculated as a percentage !! let's say a part of a whole. Means the part is divided by the whole number and multiplied by 100%.
Then 10002000 * 100% = 50. And so each specific gravity needs to be calculated.
To calculate the specific weight of some indicator as a percentage of the total part, you need to directly divide the value of this indicator by the value of the total part and multiply the resulting number by one hundred percent. This will give you the specific gravity as a percentage.
Specific gravity, as a physical indicator, is calculated by the formula:
Where P is the weight
and V is the volume.
The specific gravity as a percentage is calculated by a simple ratio Whole specific gravity to Parts of the specific gravity;. To get a percentage, you need to multiply the final result by 100:
Determination of specific gravity
The physical quantity, which is the ratio of the weight of the material to the volume it occupies, is called the HC of the material.
Materials science of the XXI century has gone far ahead in and already mastered technologies that were considered fiction some hundred years ago. This science can offer the modern industry alloys that differ from each other in quality parameters, but also in physical and technical properties.
To determine how a certain alloy can be used for production, it is advisable to determine the HC. All items made with the same volume, but different types of metals were used for their production, will have a different mass, it is in a clear connection with the volume. That is, the ratio of volume to mass is a certain constant number characteristic of this alloy.
To calculate the density of the material, a special formula is used, which has a direct connection with the HC of the material.
By the way, HC cast iron, the main material for creating steel alloys, can be determined by the weight of 1 cm 3, reflected in grams. The more metal HC, the heavier the finished product will be.
Specific gravity formula
The formula for calculating HC looks like the ratio of weight to volume. To calculate the HC, it is permissible to use the calculation algorithm, which is described in the school physics course.
For this it is necessary to use Archimedes' law, more precisely, the definition of the force, which is buoyant. That is, a load with a certain mass and at the same time it is kept on the water. In other words, it is influenced by two forces - gravity and Archimedes.
The formula for calculating the Archimedean force is as follows
where g is the fluid shock. After the substitution, the formula takes the following form F = y × V, from here we obtain the formula for the HC of the cargo y = F / V.
Difference between weight and mass
What is the difference between weight and mass. In fact, in everyday life, it does not play any role. In fact, in the kitchen, we do not make development between the weight of the chicken and its mass, but there are serious differences between these terms.
This difference is clearly visible when solving problems related to the movement of bodies in interstellar space and not as having a relationship with our planet, and under these conditions these terms differ significantly from each other.
We can say the following, the term weight has a meaning only in the area of action of gravity, i.e. if an object is near a planet, a star, etc. Weight can be called the force with which the body presses on the obstacle between it and the source of attraction. This force is measured in newtons. As an example, you can imagine the following picture - next to a paid education there is a plate with a certain object located on its surface. The force with which the object presses against the surface of the slab will be the weight.
Body mass is directly related to inertia. If we consider this concept in detail, then we can say that mass determines the size of the gravitational field created by the body. In fact, this is one of the key characteristics of the universe. The key difference between weight and mass is that mass is independent of the distance between an object and the source of gravitational force.
To measure mass, many quantities are used - kilogram, pound, etc. There is an international SI system, in which we use the usual kilograms, grams, etc. But besides it, in many countries, for example, the British Isles, there is their own system of measures and weights, where weight is measured in pounds.
UV - what is it?
Specific gravity is the ratio of the weight of matter to its volume. In the international system of measurements, SI, it is measured as a newton per cubic meter. To solve certain problems in physics, HC is defined as follows - how much heavier the substance under examination is than water at a temperature of 4 degrees, provided that the substance and water have equal volumes.
For the most part, this definition is used in geological and biological research. Sometimes the HC calculated by this method is called the relative density.
What are the differences
As already noted, these two terms are often confused, but since weight is directly dependent on the distance between the object and the gravitational source, and mass does not depend on this, therefore the terms shock and density are different.
But it is necessary to take into account the fact that under some conditions the mass and weight may be the same. It is almost impossible to measure HC at home. But even at the level of a school laboratory, such an operation is quite easy to perform. The main thing is that the laboratory is equipped with scales with deep bowls.
The item must be weighed under normal conditions. The resulting value can be designated as X1, after which the bowl with the load is placed in water. At the same time, in accordance with Archimedes' law, the cargo will lose part of its weight. In this case, the balance beam will tilt. To achieve balance, add a weight to the other pan. Its value can be designated as X2. As a result of these manipulations, an HC will be obtained, which will be expressed as the ratio of X1 and X2. In addition to the substance in the solid state, the specific can be measured for liquids and gases. In this case, measurements can be carried out in different conditions, for example, at elevated ambient temperatures or low temperatures. To obtain the required data, devices such as a pycnometer or a hydrometer are used.
Specific gravity units
In the world, several systems of measures and weights are used, in particular, in the SI system, HC is measured in the ratio of H (Newton) to a cubic meter. In other systems, for example, the CGS for specific gravity, such a unit of measurement is used d (dyne) to a cubic centimeter.
Metals with the highest and lowest specific gravity
In addition to the fact that the concept of specific gravity is used in mathematics and physics, there are quite interesting facts, for example, about the specific gravity of metals from the periodic table. if we talk about non-ferrous metals, then the most "heavy" include gold and platinum.
These materials exceed in specific gravity such metals as silver, lead and many others. The "light" materials include magnesium with a weight lower than that of vanadium. We must not forget about radioactive materials, for example, the weight of uranium is 19.05 grams per cubic cm. That is, 1 cubic meter weighs 19 tons.
Specific gravity of other materials
Our world is hard to imagine without many materials used in production and everyday life. For example, without iron and its compounds (steel alloys). The HC of these materials fluctuates in the range of one or two units, and these are not the best results. Aluminum, for example, has a low density and low specific gravity. These indicators made it possible to use it in the aviation and space industries.
Copper and its alloys have a specific gravity comparable to that of lead. But its compounds are brass, bronze is lighter than other materials, due to the fact that substances with a lower specific gravity are used in them.
How to calculate the specific gravity of metals
How to determine HC - this question often arises among specialists employed in heavy industry. This procedure is necessary in order to determine exactly those materials that will differ from each other with improved characteristics.
One of the key features of metal alloys is which metal is the base of the alloy. That is, iron, magnesium or brass having the same volume will have a different mass.
The density of the material, which is calculated on the basis of a given formula, is directly related to the issue in question. As already noted, HC is the ratio of body weight to its volume, it must be remembered that this value can be defined as the force of gravity and volume of a certain substance.
For metals, HC and density are determined in the same proportion. It is permissible to use one more formula that allows you to calculate the HC. It looks like this SW (density) is equal to the ratio of weight and mass, taking into account g, a constant value. We can say that the hydrocarbon of a metal can be called the weight of a unit of volume. In order to determine HC it is necessary to divide the dry material mass by its volume. In fact, this formula can be used to get the weight of the metal.
By the way, the concept of specific gravity is widely used in the creation of metal calculators used to calculate the parameters of rolled metal of various types and purposes.
The HC of metals is measured in qualified laboratories. In practical terms, this term is rarely used. Much more often, the concept of light and heavy metals is used, metals with a low specific gravity are classified as light, respectively, metals with a high specific gravity are classified as heavy.
Difference between weight and mass
To begin with, it is worth discussing the difference, which in everyday life is completely unimportant. But if you are solving physical problems about the motion of bodies in space that is not connected with the surface of the planet Earth, then the differences that we will cite are very significant. So, let's describe what is the difference between weight and mass.
Determination of weight
Weight makes sense only in the field of gravity, that is, near large objects. In other words, if a person is in the gravitational zone of a star, planet, large satellite or a decent-sized asteroid, then the weight is the force exerted by the body on the obstacle between him and the source of gravity in a stationary frame of reference. This value is measured in newtons. Imagine that there is a star hanging in space, at some distance from it there is a stone slab, and an iron ball lies on the slab. This is the force with which he presses on the obstacle, such will be the weight.
As you know, gravity depends on the distance and mass of the attracting object. That is, if the ball lies far from a heavy star or close to a small and relatively light planet, then it will act on the plate in the same way. But at different distances from the source of gravity, the resistance force of the same object will be different. What does it mean? If a person moves within the same city, then nothing. But if we are talking about a climber or a diver, then let him know: deep under the ocean, closer to the core, objects have more weight than at sea level, and high in the mountains - less. However, within our planet (by the way, not the largest, even in the solar system), the difference is not so significant. It becomes noticeable when going into outer space, outside the atmosphere.
Determination of mass
Mass is closely related to inertia. If you go deeper, then it determines what gravitational field the body creates. This physical quantity is one of the most fundamental characteristics. It depends only on matter at non-relativistic (that is, close to light) speeds. Unlike weight, mass does not depend on the distance to another object; it determines the strength of interaction with it.
Also, the value of the mass of the object is invariant to the system in which it is determined. It is measured in such quantities as a kilogram, a ton, a pound (not to be confused with a foot) and even a stone (which in English means "stone"). It all depends on what country a person lives in.
Determination of specific gravity
Now that the reader has figured out this important difference between two similar concepts and does not confuse them with each other, we will move on to what is specific gravity. This term denotes the ratio of the weight of a substance to its volume. In the universal SI system, it is designated as newton per cubic meter. Note that the definition refers to a substance that is mentioned either in a purely theoretical (usually chemical) aspect, or in relation to homogeneous bodies.
In some problems solved in specific areas of physical knowledge, the specific gravity is calculated as the following ratio: how much the substance under study is heavier than water of four degrees Celsius with equal volumes. As a rule, this approximate and relative value is used in sciences related, rather, to biology or geology. This conclusion is based on the fact that the indicated temperature is the average in the ocean for the planet. In another way, the specific gravity, determined by the second method, can be called the relative density.
Difference between specific gravity and density
The ratio that determines this value is easily confused with density, since it is mass divided by volume. However, weight, as we have already found out, depends on the distance to the source of gravity and its mass, and these concepts are different. It should be noted that under certain conditions, namely, at a low (nonrelativistic) speed, constant g, and small accelerations, density and specific gravity can numerically coincide. This means that by calculating two quantities, you can get the same value for them. When the above conditions are met, such a coincidence may lead to the idea that these two concepts are one and the same. This delusion is dangerous due to the fundamental difference between the properties laid down in their foundation.
Specific gravity measurement
At home, it is difficult to obtain the specific gravity of metals and other solids. However, in the simplest laboratory equipped with a balance with deep bowls, say, in a school, this will not be difficult. A metal object is weighed under normal conditions - that is, simply in air. We will register this value as x1. Then the bowl containing the object is immersed in water. At the same time, he loses weight according to the well-known Archimedes law. The device loses its original position, the rocker tilts. A weight is added for balancing. We denote its value by x2.
The specific gravity of the body will be the ratio of x1 to x2. In addition to metals, specific gravity is measured for substances in various states of aggregation, at unequal pressure, temperature, and other characteristics. To determine the desired value, methods of weighing, pycnometer, hydrometer are used. In each specific case, such experimental setups should be selected that take into account all factors.
Substances with the highest and lowest specific gravity
In addition to pure mathematical and physical theory, peculiar records are of interest. Here we will try to cite those elements of the chemical system that have the highest and lowest recorded specific gravity. Among the non-ferrous metals, the most "heavy" are the noble platinum and gold, followed by tantalum, named after the ancient Greek hero. The first two substances in terms of specific gravity are almost twice the similar values of the following silver, molybdenum and lead. Well, magnesium became the lightest among the noble metals, which is almost six times less than the slightly heavier vanadium.
Specific gravity values of some other substances
The world of our time would be impossible without iron and its various alloys, and their specific gravity undoubtedly depends on their composition. Its value varies within one or two units, but on average, these are not the highest rates among all substances. What can we say about aluminum? Like its density, its specific gravity is very low - only twice as much magnesium. This is a significant advantage for the construction of high-rise buildings, for example, or aircraft, especially when combined with properties such as strength and ductility.
But copper has a very high specific gravity, almost on a par with silver and lead. Moreover, its alloys, bronze and brass, are slightly lighter due to other metals having a lower value of the discussed value. A very beautiful and incredibly expensive diamond has rather a low specific gravity - only three times that of magnesium. Silicon and germanium, without which modern miniature gadgets would be impossible, despite the fact that they have similar structures, nevertheless differ. The specific gravity of the former is almost half that of the latter, although both are relatively light substances on this scale.
The calculation of the proportion of workers is one of the most common calculations in the study of personnel. The analysis of quantitative and qualitative indicators of personnel is very often used when writing term papers and theses. Therefore, we will try to consider further what options for calculating the proportion of workers can be. In fact, the calculation of the specific gravity is nothing more than the relative size of the structure (you can see more about the general rules for calculating this value). The calculation of the structure of the phenomenon (specific gravity) is always carried out according to the same formula.
The formula for calculating the specific gravity is:
The calculation for each period is the same, so here is the calculation for 2009
Share of managers = 17/96 * 100 = 18%
The proportion of specialists = 38/96 * 100 = 40%
Share of employees = 19/96 * 100 = 20%
The proportion of workers = 14/96 * 100 = 14%
Specific gravity of MOS = 8/96 * 100 = 8%
We enter the calculation results in the table.
Table 1. Personnel structure of LLC "Quartz"
| Personnel category | 2009 | 2010 | 2011 | |||
| number, people | beats the weight, % | number, people | beats the weight, % | number, people | beats the weight, % | |
| Leaders | 17 | 18 | 17 | 17 | 17 | 18 |
| Specialists | 38 | 40 | 39 | 40 | 35 | 38 |
| Employees | 19 | 20 | 20 | 21 | 21 | 22 |
| Workers | 14 | 14 | 14 | 14 | 13 | 14 |
| MNP | 8 | 8 | 8 | 8 | 8 | 9 |
| Total: | 96 | 100 | 98 | 100 | 94 | 100 |
It should be noted that the share of specialists decreased in 2011 compared to 2009 and 2010 from 40% to 38%. But at the same time, in 2011, the share of employees was caught up to 22%.
Figure 1. Personnel structure of LLC "Quartz" by category in 2009-2011
It can be seen from the figure that the main personnel at Quartz LLC are specialists, since it is on their work that the effective activity of the company depends, and the receipt of profit by it. Despite the decline in the share of specialists in 2011 to 38%, this group occupies a larger share in the personnel structure.
Let's calculate the specific weight (share) of each age group.
Specific gravity up to 25 = 67/223 * 100 = 30.0%
Specific gravity from 25 to 40 = 113/223 * 100 = 50.7%
Specific gravity from 40 to 50 = 26/223 * 100 = 11.7%
Specific gravity from 50 to 60 = 14/223 * 100 = 6.3%
Share over 60 = 3/223 * 100 = 1.3%
The calculation results are presented in Table 2.
Table 2. Age structure of the personnel of "Yarkiy Mir" LLC for the period 2011-2013.
| Age, years | 2011 | 2012 | 2013 | |||
| number, people | share,% | number, people | share,% | number, people | share,% | |
| up to 25 | 67 | 30,0 | 61 | 31,1 | 57 | 31,3 |
| from 25 to 40 | 113 | 50,7 | 97 | 49,5 | 89 | 48,9 |
| from 40 to 50 | 26 | 11,7 | 24 | 12,2 | 23 | 12,6 |
| from 50 to 60 | 14 | 6,3 | 12 | 6,1 | 11 | 6,0 |
| over 60 | 3 | 1,3 | 2 | 1,1 | 2 | 1,2 |
| Total: | 223 | 100 | 196 | 100 | 182 | 100 |
As can be seen from Table 2, there are no significant fluctuations in age groups in Yarkiy Mir LLC, however, one can notice a certain dynamics of shares in the first two age groups - up to 25 years old and from 25 to 45 years old. The share of the group of employees with the age of up to 25 years gradually increased from 2011 to 2013 and amounted to 31.3%, an increase in relation to 2011 of 1.3%. At the same time, the share of the group aged 25 to 45 was gradually decreasing and in 2011 amounted to 48.9%, the decrease in the share in relation to 2011 was 1.8%. This dynamics suggests that employees who have some experience and are most likely not satisfied with the remuneration policy are leaving the organization to a greater extent. The arrival of younger employees to replace those who left also confirms this fact. This is a disadvantage of the organization's personnel policy.
Personnel structure by educational level
Let's analyze the structure of personnel by education, Table 3.
Let's calculate the specific weight (share) of each level of education.
Age structure of personnel in 2011.
Specific gravity of joint venture and CO = 24/223 * 100 = 10.80%
Share of NGOs = 33/223 * 100 = 14.8%
Specific gravity of SPO = 127/223 * 100 = 57.0%
Specific gravity of HPO = 39/223 * 100 = 17.5%
The calculation results are presented in Table 3.
Table 3. The structure of the personnel of LLC "Yarkiy Mir" by education for 2011-2013.
| Age, years | 2011 | 2012 | 2013 | |||
| number, people | share,% | number, people | share,% | number, people | share,% | |
| Secondary complete and secondary general | 24 | 10,8 | 21 | 10,7 | 20 | 11,0 |
| Initial vocational | 33 | 14,8 | 29 | 14,8 | 28 | 15,4 |
| Secondary vocational | 127 | 57,0 | 108 | 55,1 | 96 | 52,7 |
| Higher professional | 39 | 17,5 | 38 | 19,4 | 38 | 20,9 |
| Total: | 223 | 100 | 196 | 100 | 182 | 100 |
As you can see from table 3, the structure of employees of LLC "Bright World" does not have any special changes. For all three years, the largest share is occupied by employees with secondary vocational education (57.0-52.7%), the share of employees with higher education was 17.5-20.9%.
Let's calculate the specific weight (share) of personnel by the duration of production experience.
Share of personnel by length of service in 2011.
Specific gravity up to 2 years = 112/223 * 100 = 50.2%
Specific gravity from 2 to 5 = 98/223 * 100 = 43.9%
Specific gravity from 5 to 10 = 11/223 * 100 = 4.9%
Specific gravity from 10 and more = 2/223 * 100 = 1.0%
The calculation results are presented in Table 4.
Table 4. The structure of the personnel of LLC "Yarkiy Mir" by the length of service for the period 2011-2013.
| Production experience, years | 2011 | 2012 | 2013 | |||
| number, people | share,% | number, people | share,% | number, people | share,% | |
| up to 2 years | 112 | 50,2 | 102 | 52,0 | 94 | 51,6 |
| from 2 to 5 | 98 | 43,9 | 79 | 40,3 | 72 | 39,6 |
| from 5 to 10 | 11 | 4,9 | 13 | 6,6 | 14 | 7,6 |
| from 10 and more | 2 | 1,0 | 2 | 1,1 | 2 | 1,2 |
| Total: | 223 | 100 | 196 | 100 | 182 | 100 |
The largest share in terms of length of service, as can be seen from table 4, in LLC "Bright World" is occupied by employees who have worked in the organization for no more than two years, this indicator fluctuates at the level of 50-52%. This indicates that employees are not doing to stay for a long time in the organization. There can be several explanations for this - low pay, low prestige, poorly built incentive system, etc. in addition, the share of employees who have worked in the organization from 2 to 5 years has decreased. During the downsizing period, many workers found higher-paying jobs.
Share of personnel by gender in 2011.
Share of men = 85/223 * 100 = 38.2%
Share of women = 138/223 * 100 = 61.8%
The calculation results are presented in Table 5.
Table 5. The structure of the personnel of LLC "Yarkiy Mir" by gender for the period 2011-2013.
| Floor | 2011 | 2012 | 2013 | |||
| number, people | share,% | number, people | share,% | number, people | share,% | |
| male | 85 | 38,2 | 75 | 38,1 | 69 | 37,9 |
| female | 138 | 61,8 | 121 | 61,9 | 113 | 62,1 |
| Total: | 223 | 100 | 196 | 100 | 182 | 100 |
The share of men is at 38%, the share of women is 62%, there are no significant changes in the shares by gender in the organization.
Among the many parameters that characterize the properties of materials, there is such as specific gravity. The term density is sometimes used, but this is not entirely true. But one way or another, these both terms have their own definitions and are in circulation in mathematics, physics and many other sciences, including materials science.
Determination of specific gravity
The physical quantity, which is the ratio of the weight of the material to the volume it occupies, is called the HC of the material.
Materials science of the XXI century has gone far ahead in and already mastered technologies that were considered fiction some hundred years ago. This science can offer the modern industry alloys that differ from each other in quality parameters, but also in physical and technical properties.
To determine how a certain alloy can be used for production, it is advisable to determine the HC. All items made with the same volume, but different types of metals were used for their production, will have a different mass, it is in a clear connection with the volume. That is, the ratio of volume to mass is a certain constant number characteristic of this alloy.
To calculate the density of the material, a special formula is used, which has a direct connection with the HC of the material.
By the way, HC cast iron, the main material for creating steel alloys, can be determined by the weight of 1 cm 3, reflected in grams. The more metal HC, the heavier the finished product will be.
Specific gravity formula
The formula for calculating HC looks like the ratio of weight to volume. To calculate the HC, it is permissible to use the calculation algorithm, which is described in the school physics course.
For this it is necessary to use Archimedes' law, more precisely, the definition of the force, which is buoyant. That is, a load with a certain mass and at the same time it is kept on the water. In other words, it is influenced by two forces - gravity and Archimedes.
The formula for calculating the Archimedean force is as follows
where g is the fluid shock. After the substitution, the formula takes the following form F = y × V, from here we obtain the formula for the HC of the cargo y = F / V.
Difference between weight and mass
What is the difference between weight and mass. In fact, in everyday life, it does not play any role. In fact, in the kitchen, we do not make development between the weight of the chicken and its mass, but there are serious differences between these terms.
This difference is clearly visible when solving problems related to the movement of bodies in interstellar space and not as having a relationship with our planet, and under these conditions these terms differ significantly from each other.
We can say the following, the term weight has a meaning only in the area of action of gravity, i.e. if an object is near a planet, a star, etc. Weight can be called the force with which the body presses on the obstacle between it and the source of attraction. This force is measured in newtons. As an example, you can imagine the following picture - next to a paid education there is a plate with a certain object located on its surface. The force with which the object presses against the surface of the slab will be the weight.
Body mass is directly related to inertia. If we consider this concept in detail, then we can say that mass determines the size of the gravitational field created by the body. In fact, this is one of the key characteristics of the universe. The key difference between weight and mass is that mass is independent of the distance between an object and the source of gravitational force.
To measure mass, many quantities are used - kilogram, pound, etc. There is an international SI system, in which we use the usual kilograms, grams, etc. But besides it, in many countries, for example, the British Isles, there is their own system of measures and weights, where weight is measured in pounds.
Difference between specific gravity and density
UV - what is it?
Specific gravity is the ratio of the weight of matter to its volume. In the international system of measurements, SI, it is measured as a newton per cubic meter. To solve certain problems in physics, HC is defined as follows - how much heavier the substance under examination is than water at a temperature of 4 degrees, provided that the substance and water have equal volumes.
For the most part, this definition is used in geological and biological research. Sometimes the HC calculated by this method is called the relative density.
What are the differences
As already noted, these two terms are often confused, but since weight is directly dependent on the distance between the object and the gravitational source, and mass does not depend on this, therefore the terms shock and density are different.
But it is necessary to take into account the fact that under some conditions the mass and weight may be the same. It is almost impossible to measure HC at home. But even at the level of a school laboratory, such an operation is quite easy to perform. The main thing is that the laboratory is equipped with scales with deep bowls.
The item must be weighed under normal conditions. The resulting value can be designated as X1, after which the bowl with the load is placed in water. At the same time, in accordance with Archimedes' law, the cargo will lose part of its weight. In this case, the balance beam will tilt. To achieve balance, add a weight to the other pan. Its value can be designated as X2. As a result of these manipulations, an HC will be obtained, which will be expressed as the ratio of X1 and X2. In addition to the substance in the solid state, the specific can be measured for liquids and gases. In this case, measurements can be carried out in different conditions, for example, at elevated ambient temperatures or low temperatures. To obtain the required data, devices such as a pycnometer or a hydrometer are used.
Specific gravity units
In the world, several systems of measures and weights are used, in particular, in the SI system, HC is measured in the ratio of H (Newton) to a cubic meter. In other systems, for example, the CGS for specific gravity, such a unit of measurement is used d (dyne) to a cubic centimeter.
Metals with the highest and lowest specific gravity
In addition to the fact that the concept of specific gravity is used in mathematics and physics, there are quite interesting facts, for example, about the specific gravity of metals from the periodic table. if we talk about non-ferrous metals, then the most "heavy" include gold and platinum.
These materials exceed in specific gravity such metals as silver, lead and many others. The "light" materials include magnesium with a weight lower than that of vanadium. We must not forget about radioactive materials, for example, the weight of uranium is 19.05 grams per cubic cm. That is, 1 cubic meter weighs 19 tons.
Specific gravity of other materials
Our world is hard to imagine without many materials used in production and everyday life. For example, without iron and its compounds (steel alloys). The HC of these materials fluctuates in the range of one or two units, and these are not the best results. Aluminum, for example, has a low density and low specific gravity. These indicators made it possible to use it in the aviation and space industries.
Copper and its alloys have a specific gravity comparable to that of lead. But its compounds are brass, bronze is lighter than other materials, due to the fact that substances with a lower specific gravity are used in them.
How to calculate the specific gravity of metals
How to determine HC - this question often arises among specialists employed in heavy industry. This procedure is necessary in order to determine exactly those materials that will differ from each other with improved characteristics.
One of the key features of metal alloys is which metal is the base of the alloy. That is, iron, magnesium or brass having the same volume will have a different mass.
The density of the material, which is calculated on the basis of a given formula, is directly related to the issue in question. As already noted, HC is the ratio of body weight to its volume, it must be remembered that this value can be defined as the force of gravity and volume of a certain substance.
For metals, HC and density are determined in the same proportion. It is permissible to use one more formula that allows you to calculate the HC. It looks like this SW (density) is equal to the ratio of weight and mass, taking into account g, a constant value. We can say that the hydrocarbon of a metal can be called the weight of a unit of volume. In order to determine HC it is necessary to divide the dry material mass by its volume. In fact, this formula can be used to get the weight of the metal.
By the way, the concept of specific gravity is widely used in the creation of metal calculators used to calculate the parameters of rolled metal of various types and purposes.
The HC of metals is measured in qualified laboratories. In practical terms, this term is rarely used. Much more often, the concept of light and heavy metals is used, metals with a low specific gravity are classified as light, respectively, metals with a high specific gravity are classified as heavy.
