Normal atmospheric pressure for humans. mm Hg in atmospheres High and low atmospheric pressure

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1 pascal [Pa] = 0.00750063755419211 millimeter of mercury (0°C) [mmHg]

Initial value

Converted value

pascal exapascal petapascal terapascal gigapascal megapascal kilopascal hectopascal decapascal decipascal centipascal millipascal micropascal nanopascal picopascal femtopascal attopascal newton per sq. newton meter per sq. centimeter newton per sq. millimeter kilonewton per sq. meter bar millibar microbar dynes per sq. centimeter kilogram-force per sq. meter kilogram-force per sq. centimeter kilogram-force per sq. millimeter gram-force per sq. centimeter ton-force (short) per sq. ft ton-force (short) per sq. inch ton-force (L) per sq. ft ton-force (L) per sq. inch kilopound-force per sq. inch kilopound-force per sq. inch lbf/sq. ft lbf/sq. inch psi poundal per sq. ft torr centimeter of mercury (0°C) millimeter of mercury (0°C) inch of mercury (32°F) inch of mercury (60°F) centimeter of water column (4°C) mm w.c. column (4°C) inch w.c. column (4°C) foot of water (4°C) inch of water (60°F) foot of water (60°F) technical atmosphere physical atmosphere decibar walls per square meter pieze barium (barium) Planck pressure meter sea water foot sea water (at 15 ° C) meter of water. column (4°C)

More about pressure

General information

In physics, pressure is defined as the force acting per unit area of a surface. If two identical forces act on one large and one smaller surface, then the pressure on the smaller surface will be greater. Agree, it is much worse if the owner of studs steps on your foot than the mistress of sneakers. For example, if you press the blade of a sharp knife on a tomato or carrot, the vegetable will be cut in half. The surface area of the blade in contact with the vegetable is small, so the pressure is high enough to cut through the vegetable. If you press with the same force on a tomato or carrot with a blunt knife, then most likely the vegetable will not be cut, since the surface area of \u200b\u200bthe knife is now larger, which means the pressure is less.

In the SI system, pressure is measured in pascals, or newtons per square meter.

Relative pressure

Sometimes pressure is measured as the difference between absolute and atmospheric pressure. This pressure is called relative or gauge pressure and it is measured, for example, when checking the pressure in car tires. Measuring instruments often, although not always, indicate relative pressure.

Atmosphere pressure

Atmospheric pressure is the air pressure at a given location. It usually refers to the pressure of a column of air per unit surface area. A change in atmospheric pressure affects the weather and air temperature. People and animals suffer from severe pressure drops. Low blood pressure causes problems in people and animals of varying severity, from mental and physical discomfort to fatal diseases. For this reason, aircraft cabins are maintained at a pressure above atmospheric pressure at a given altitude because the atmospheric pressure at cruising altitude is too low.

Atmospheric pressure decreases with altitude. People and animals living high in the mountains, such as the Himalayas, adapt to such conditions. Travelers, on the other hand, should take the necessary precautions so as not to get sick because the body is not accustomed to such low pressure. Climbers, for example, can get altitude sickness associated with a lack of oxygen in the blood and oxygen starvation of the body. This disease is especially dangerous if you stay in the mountains for a long time. Exacerbation of altitude sickness leads to serious complications, such as acute mountain sickness, high-altitude pulmonary edema, high-altitude cerebral edema, and the most acute form of mountain sickness. The danger of altitude and mountain sickness begins at an altitude of 2400 meters above sea level. To avoid altitude sickness, doctors advise avoiding depressants such as alcohol and sleeping pills, drinking plenty of fluids, and ascending altitude gradually, such as on foot rather than in transport. It's also good to eat plenty of carbohydrates and get plenty of rest, especially if the climb is fast. These measures will allow the body to get used to the lack of oxygen caused by low atmospheric pressure. If these guidelines are followed, the body will be able to produce more red blood cells to transport oxygen to the brain and internal organs. To do this, the body will increase the pulse and respiratory rate.

First aid in such cases is provided immediately. It is important to move the patient to a lower altitude where atmospheric pressure is higher, preferably lower than 2400 meters above sea level. Drugs and portable hyperbaric chambers are also used. These are lightweight, portable chambers that can be pressurized with a foot pump. A patient with mountain sickness is placed in a chamber in which pressure is maintained corresponding to a lower altitude above sea level. Such a chamber is used only for first aid, after which the patient must be lowered.

Some athletes use low blood pressure to improve circulation. Usually, for this, training takes place under normal conditions, and these athletes sleep in a low-pressure environment. Thus, their body gets used to high altitude conditions and begins to produce more red blood cells, which in turn increases the amount of oxygen in the blood, and allows them to achieve better results in sports. For this, special tents are produced, the pressure in which is regulated. Some athletes even change the pressure throughout the bedroom, but sealing the bedroom is an expensive process.

suits

Pilots and astronauts have to work in a low pressure environment, so they work in spacesuits that allow them to compensate for the low pressure of the environment. Space suits completely protect a person from the environment. They are used in space. Altitude compensation suits are used by pilots at high altitudes - they help the pilot breathe and counteract low barometric pressure.

hydrostatic pressure

Hydrostatic pressure is the pressure of a fluid caused by gravity. This phenomenon plays a huge role not only in engineering and physics, but also in medicine. For example, blood pressure is the hydrostatic pressure of blood against the walls of blood vessels. Blood pressure is the pressure in the arteries. It is represented by two values: systolic, or the highest pressure, and diastolic, or the lowest pressure during the heartbeat. Devices for measuring blood pressure are called sphygmomanometers or tonometers. The unit of blood pressure is millimeters of mercury.

The Pythagorean mug is an entertaining vessel that uses hydrostatic pressure, specifically the siphon principle. According to legend, Pythagoras invented this cup to control the amount of wine he drank. According to other sources, this cup was supposed to control the amount of water drunk during a drought. Inside the mug is a curved U-shaped tube hidden under the dome. One end of the tube is longer, and ends with a hole in the stem of the mug. The other, shorter end is connected by a hole to the inner bottom of the mug so that the water in the cup fills the tube. The principle of operation of the mug is similar to the operation of a modern toilet tank. If the liquid level rises above the level of the tube, the liquid overflows into the other half of the tube and flows out due to the hydrostatic pressure. If the level, on the contrary, is lower, then the mug can be safely used.

pressure in geology

Pressure is an important concept in geology. Without pressure, it is impossible to form gemstones, both natural and artificial. High pressure and high temperature are also necessary for the formation of oil from the remains of plants and animals. Unlike gems, which are mostly found in rocks, oil forms at the bottom of rivers, lakes, or seas. Over time, more and more sand accumulates over these remnants. The weight of water and sand presses on the remains of animal and plant organisms. Over time, this organic material sinks deeper and deeper into the earth, reaching several kilometers below the earth's surface. The temperature rises by 25°C for every kilometer below the earth's surface, so at a depth of several kilometers the temperature reaches 50-80°C. Depending on the temperature and temperature difference in the formation medium, natural gas may be formed instead of oil.

natural gems

The formation of gemstones is not always the same, but pressure is one of the main components of this process. For example, diamonds are formed in the Earth's mantle, under conditions of high pressure and high temperature. During volcanic eruptions, diamonds move to the upper layers of the Earth's surface due to magma. Some diamonds come to Earth from meteorites, and scientists believe they were formed on Earth-like planets.

Synthetic gems

The production of synthetic gemstones began in the 1950s and has been gaining popularity in recent years. Some buyers prefer natural gemstones, but artificial gemstones are becoming more and more popular due to the low price and lack of problems associated with natural gemstone mining. Thus, many buyers choose synthetic gemstones because their extraction and sale is not associated with the violation of human rights, child labor and the financing of wars and armed conflicts.

One of the technologies for growing diamonds in the laboratory is the method of growing crystals at high pressure and high temperature. In special devices, carbon is heated to 1000 ° C and subjected to a pressure of about 5 gigapascals. Typically, a small diamond is used as the seed crystal, and graphite is used for the carbon base. A new diamond grows from it. This is the most common method of growing diamonds, especially as gemstones, due to its low cost. The properties of diamonds grown in this way are the same or better than those of natural stones. The quality of synthetic diamonds depends on the method of their cultivation. Compared to natural diamonds, which are most often transparent, most artificial diamonds are colored.

Due to their hardness, diamonds are widely used in manufacturing. In addition, their high thermal conductivity, optical properties and resistance to alkalis and acids are highly valued. Cutting tools are often coated with diamond dust, which is also used in abrasives and materials. Most of the diamonds in production are of artificial origin due to the low price and because the demand for such diamonds exceeds the ability to mine them in nature.

Some companies offer services to create memorial diamonds from the ashes of the deceased. To do this, after cremation, the ashes are cleaned until carbon is obtained, and then a diamond is grown on its basis. Manufacturers advertise these diamonds as a memory of the departed, and their services are popular, especially in countries with a high percentage of wealthy citizens, such as the United States and Japan.

Crystal growth method at high pressure and high temperature

The high pressure, high temperature crystal growth method is mainly used to synthesize diamonds, but more recently, this method has been used to improve natural diamonds or change their color. Different presses are used to artificially grow diamonds. The most expensive to maintain and the most difficult of these is the cubic press. It is mainly used to enhance or change the color of natural diamonds. Diamonds grow in the press at a rate of approximately 0.5 carats per day.

Do you find it difficult to translate units of measurement from one language to another? Colleagues are ready to help you. Post a question to TCTerms and within a few minutes you will receive an answer.

Many people are subject to changes in the environment. A third of the population is affected by the attraction of air masses to the earth. Atmospheric pressure: the norm for a person, and how deviations from the indicators affect the general well-being of people.

Changes in the weather can affect the human condition

What atmospheric pressure is considered normal for a person

Atmospheric pressure is the weight of air that presses on the human body. On average, this is 1.033 kg per 1 cubic cm. That is, 10-15 tons of gas control our mass every minute.

The norm of atmospheric pressure is 760 mmHg or 1013.25 mbar. Conditions in which the human body feels comfortable or adapted. In fact, the ideal weather indicator for any inhabitant of the Earth. In reality, everything is not so.

Atmospheric pressure is not stable. Its changes are daily and depend on the weather, relief, level above the sea, climate and even the time of day. Fluctuations are not noticeable to humans. For example, at night, the mercury column rises 1-2 divisions higher. Minor changes do not affect the well-being of a healthy person. Drops of 5-10 or more units are painful, and sharp significant jumps are fatal. For comparison: loss of consciousness from altitude sickness occurs already when the pressure drops by 30 units. That is, at the level of 1000 m above the sea.

A continent and even a separate country can be divided into conditional areas with different norms of average pressure. Therefore, the optimal atmospheric pressure for each person is determined by the region of permanent residence.

High air pressure adversely affects hypertension

Such weather conditions are generous for strokes and heart attacks.

Persons who are vulnerable to the vagaries of nature are advised by doctors on such days to stay outside the zone of active work and deal with the consequences of meteorological dependence.

Meteorological dependence - what to do?

The movement of mercury by more than one division in 3 hours is a reason for stress in a strong organism of a healthy person. Each of us feels such fluctuations in the form of a headache, drowsiness, fatigue. More than a third of people suffer from weather dependence in varying degrees of severity. In the zone of high sensitivity, the population with diseases of the cardiovascular, nervous and respiratory systems, the elderly. How to help yourself if a dangerous cyclone is approaching?

15 Ways to Survive a Weather Cyclone

Not much new advice has been collected here. It is believed that together they alleviate suffering and teach the right way of life with meteorological vulnerability:

See your doctor regularly. Consult, discuss, ask for advice in case of deterioration of health. Have your prescribed medications handy at all times.
Buy a barometer. It is more productive to track the weather by the movement of the mercury column, rather than knee pain. So you will be able to anticipate the impending cyclone.
Watch the weather forecast. Forewarned is forearmed.
On the eve of a change in weather, get enough sleep and go to bed earlier than usual.
Set up a sleep schedule. Get yourself a full 8-hour sleep, getting up and falling asleep at the same time. This has a powerful restorative effect.
The meal schedule is equally important. Follow a balanced diet. Potassium, magnesium and calcium are essential minerals. Overeating ban.
Drink vitamins in a course in spring and autumn.
Fresh air, walking outside - light and regular exercise strengthens the heart.
Don't overstress. Postponing household chores is not as dangerous as weakening the body before a cyclone.
Accumulate favorable emotions. An oppressed emotional background fuels the disease, so smile more often.
Clothing made of synthetic threads and fur is harmful to static current.
Keep folk remedies for relieving symptoms in a list in a conspicuous place. The recipe for herbal tea or compress is hard to remember when whiskey ache.
Office workers in high-rise buildings suffer from weather changes more often. Take a day off if possible, or better yet, change jobs.
A long cyclone is discomfort for several days. Is it possible to go to a quiet region? Forward.
Prevention at least a day before the cyclone prepares and strengthens the body. Do not give up!

Don't Forget to Take Vitamins for Health

Atmosphere pressure- This is a phenomenon that is absolutely independent of a person. Moreover, our body obeys him. What should be the optimal pressure for a person determines the region of residence. People with chronic diseases are especially susceptible to meteorological dependence.

1 pascal [Pa] = 0.00750063755419211 millimeter of mercury (0°C) [mmHg]

Initial value

Converted value

More about pressure

General information

In the SI system, pressure is measured in pascals, or newtons per square meter.

Relative pressure

Atmosphere pressure

suits

hydrostatic pressure

pressure in geology

natural gems

Synthetic gems

Crystal growth method at high pressure and high temperature

1 millimeter of mercury (0°C) [mmHg] = 0.0013595060494664 technical atmosphere [at]

Initial value

Converted value

Thermal resistance

More about pressure

General information

In the SI system, pressure is measured in pascals, or newtons per square meter.

Relative pressure

Atmosphere pressure

suits

hydrostatic pressure

pressure in geology

natural gems

Synthetic gems

Crystal growth method at high pressure and high temperature

In weather forecasts, barometric pressure is often expressed in mmHg. In science, more conventional units are used - Pascals. Of course, there is a clear connection between them.

Instruction

1. Pascal is the SI unit for pressure. Pascal has the unit of kg/ms². 1 Pascal is the pressure that exerts a force of 1 Newton per 1 m² of area.

2. 1 mm of mercury is a non-systemic unit of pressure, it is used in relation to the pressure of gases: atmosphere, water vapor, vacuum. The name describes the physical essence of this unit: such pressure on the base is a mercury column 1 mm high. The exact, physical, definition of the unit also includes the density of mercury and the acceleration of free fall.

3. 1 mm Hg = 133.322 N / m² or 133 Pa. Thus, if we talk about a pressure of 760 mm Hg, then in Pascals we get the following: 760 * 133.322 \u003d 101325 Pa, or approximately 101 kPa.

Pressure- a physical quantity that shows how much force acts on a particular surface. Bodies whose substances are in different states of aggregation (solid, liquid and gaseous) exert pressure by perfectly different methods. For example, if you put a piece of cheese in a jar, then it will only press on the bottom of the jar, and the milk poured into the same place acts with force on the bottom and walls of the vessel. In the international system of measurement, pressure is measured in pascals. But there are other units of measurement: millimeters of mercury, newtons divided by kilograms, kilos pascals, hecto pascals etc. The relationship between these quantities is established mathematically.

Instruction

1. The Pascal unit of pressure is named after the French scientist Blaise Pascal. It is designated as follows: Pa. When solving problems and in practice, quantities that have multiples or submultiple decimal prefixes are applicable. Let's say kilo pascals, hecto pascals, milli pascals, mega pascals etc. To convert these values to pascals, you need to know the mathematical value of the prefix. All available prefixes can be found in any physical directory. Example1. 1 kPa = 1000 Pa (one kilopascal is equal to one thousand pascals). 1 hPa = 100 Pa (one hectopascal is equal to one hundred pascals). 1mPa = 0.001Pa (one millipascal is equal to zero integers, one thousandth of a pascal).

2. Pressure solids are usually measured in pascals. But what is physically equal to one pascal? Based on the definition of pressure, the formula for its calculation is calculated and the unit of measurement is displayed. Pressure equal to the ratio of the force acting perpendicular to the support to the surface area of this support. p=F/S, where p is the pressure, measured in Pascals, F is the force, measured in Newtons, S is the surface area, measured in square meters. It turns out that 1 Pa \u003d 1N / (m) squared. Example 2. 56 N/(m) squared = 56 Pa.

3. Pressure The air envelope of the Earth is usually called atmospheric pressure and is measured not in pascals, but in millimeters of mercury (hereinafter, mm Hg). In 1643, the Italian scientist Torricelli proposed a skill for measuring atmospheric pressure, in which a glass tube with mercury was used (see “mercury column”). He also measured that the typical pressure of the atmosphere is 760 mm Hg. Art., which is numerically equal to 101325 pascals. Then, 1 mm Hg. ~ 133.3 Pa. In order to convert millimeters of mercury to pascals, you need to multiply this value by 133.3. Example 3. 780 mmHg Art. \u003d 780 * 133.3 \u003d 103974 Pa ~ 104 kPa.

In 1960, the International System of Units (SI) entered into force, in which Newton was included as a unit of force. This is a "derived unit", that is, it can be expressed in terms of other SI units. According to Newton's second law, the force is equal to the product of the body's mass and its acceleration. Mass in the SI system is measured in kilograms, and acceleration in meters and seconds, therefore 1 Newton is defined as the product of 1 kilogram by 1 meter divided by a second squared.

Instruction

1. Use the exponent 0.10197162 to convert to Newtons quantities measured in units with the name "kilogram-force" (denoted as kgf or kg). Such units are often used in calculations in construction, because they are prescribed in the regulatory documents SNiP (“Building Norms and Rules”). This unit considers the standard force of gravity of the Earth and one kilogram-force can be represented as the force with which a weight of one kilogram presses on the scales somewhere on the sea level near the equator of our planet. To convert the famous kgf number to Newtons, it must be divided by the above figure. Let's say 100 kgf = 100 / 0.10197162 = 980.66501 N.

2. Use your math skills and trained memory to perform mental calculations to convert quantities measured in kgf to Newtons. If there are any snags with this, then use a calculator - say, the one that Microsoft carefully inserts into the entire distribution of the Windows operating system. In order to open it, you need to delve into the main OS menu for three tiers. First, click the "Start" button to see the items of the first tier, then expand the "Programs" section to access the second, and then go to the "Typical" subsection to the lines of the third tier of the menu. Click on the one that says "Calculator".

3. Highlight and copy (CTRL + C) on this page the conversion rate from kgf to Newtons (0.10197162). After that, switch to the calculator interface and paste the copied value (CTRL + V) - it's easier than manually typing a nine-digit number. Then click the slash button and enter the famous value measured in kilogram-force units. Click the button with the equal sign and the calculator will calculate and show you the value of this quantity in Newtons.

Related videos

Bar is a unit of pressure that is not included in any system of units. However, it is used in the domestic GOST 7664-61 "Mechanical units". On the other hand, in our country the international SI system is used, in which a unit called “Pascal” is prepared for measuring pressure. Fortunately, the relationship between them is easy to remember, so converting values from one unit of measure to another is not particularly difficult.

Instruction

1. Multiply the value measured in bars by one hundred thousand in order to convert this value into Pascals. If the translated value is larger than one, then it is more comfortable to use not Pascals, but more large derivatives of it. Let's say a pressure of 20 bar is equal to 2,000,000 Pascals or 2 megaPascals.

2. Calculate the required value in your mind. This should not be difficult, because each one only needs to move the decimal point in the initial number by six places. If, nevertheless, there are any difficulties with this operation, then it is allowed to use online calculators, and even better online converters. Let's say it can be a service built into the Google search engine: it combines both a calculator and a converter. In order to use it, go to the search engine website and enter an appropriately defined search query. Say, if you need to convert a pressure value equal to 20 bar to Pascals, then the query might look like this: “20 bar to Pascals”. After entering the request, it will be sent to the server and processed mechanically, that is, it is not required to press the button in order to see the result.

3. Use the built-in Windows calculator if you don't have internet access. It also has built-in functions for converting values from one unit to another. To launch this application, press the key combination WIN + R, then type the command calc and press the Enter key.

4. Expand the "View" section in the calculator's menu and select the "Conversion" item in it. Select "Pressure" from the "Category" drop-down list. In the "Initial value" list, set "bar". In the Final Value list, click pascal.

5. Click the calculator input field, type in the famous value in bars and click the "Translate" button. The calculator will display the equivalent of this value in Pascals in the input field.

Related videos

To date, there are two systems of measurement - metric and non-metric. The latter includes inches, feet and miles, while the metric one includes millimeters, centimeters, meters and kilometers. The non-metric system of measures, as usual, is used in the USA and the countries of the British Commonwealth. Historically, it has been much easier for Americans to measure objects in inches than in meters.

Instruction

1. It has long been believed that an inch determines the average length of the phalanx of the thumb. In the old days, measurements of small objects, as usual, were carried out manually. And so it happened. After that, the inch became the official system of measures in many countries of the world. It is worth noting that the size of an inch in some countries varies within tenths of a centimeter. The accepted standard is the size of the English inch. In order to convert inches to millimeters, take a calculator and, using the ratio 1 inch \u003d 25.4 millimeters, calculate the length and dimensions of an object in the usual calculus for us. To do this, type a certain number in inches on the calculator, press “multiply” (traditionally, this mathematical parameter corresponds to the * icon), enter the number 25.4 and press “=”. The numbers that will be displayed on the monitor screen and will correspond to the length value in millimeters. If you want to convert centimeters to inches, then perform the same manipulations correctly with the support of the calculator. Only instead of the number 25.4, enter 2.54. The last number answers the question of how many centimeters are in an inch.

2. If you ever visit overseas highways, you will see that distances are measured in miles. And one mile is equal to 1.609344 kilometers. Perform simple calculations and you will find out the distance to a certain settlement in kilometers. Now, knowing how to convert inches to centimeters and millimeters, you will easily navigate in foreign length values. This is doubly significant if, on duty, you often come into contact with overseas documentation, where inch and foot values \u200b\u200bare widely used. Therefore, in order to quickly navigate these values, always have a calculator with you, one that will help you instantly convert inches to centimeters or millimeters. Traditionally, every mobile phone has a calculator. So you avoid the extra expense of buying an extra computing accessory.

Pascals (Pa, Ra) are the core system unit of pressure (SI). But much more often a multiple unit is used - kilopascal (kPa, kPa). The fact is that one pascal is a hefty small pressure by human standards. Such pressure will exert one hundred grams of liquid, evenly distributed over the surface of the coffee table. If one pascal is compared with atmospheric pressure, then it will be each only one hundred thousandth of it.

You will need

- calculator;
- pencil;
- paper.

Instruction

1. In order to convert the pressure given in pascals to kilopascals, multiply the number of pascals by 0.001 (or divide by 1000). In the form of a formula, this rule can be written as follows: Kkp = Kp * 0.001 or Kkp = Kp / 1000, where: Kkp is the number of kilopascals, Kp is the number of pascals.

2. Example: typical atmospheric pressure is considered to be 760 mmHg. Art., or 101325 pascals. Question: how many kilopascals is typical atmospheric pressure? Solution: divide the number of pascals by 1000: 101325 / 1000 \u003d 101.325 (kPa). Result: typical atmospheric pressure is 101 kilopascals.

3. To divide the number of pascals by 1000, easily move the decimal point three digits to the left (as in the example above): 101325 -> 101.325.

4. If the pressure is less than 100 Pa, then to convert it to kilopascals, add the missing insignificant zeros to the number on the left. Example: how many kilopascals will be the pressure of one pascal? Solution: 1 Pa = 0001 Pa = 0.001 kPa. Result: 0.001 kPa.

5. When solving physical problems, keep in mind that pressure can be specified in other pressure units. Exceptionally often when measuring pressure, there is such a unit as N / m? (newton per square meter). In reality, this unit is equivalent to pascal, because it is its definition.

6. Officially, the pressure unit pascal (N/m?) is also equivalent to the unit of energy density (J/m?). However, from a physical point of view, these units describe different physical properties. Therefore, do not record pressure as J/m?.

7. If a lot of other physical quantities appear in the conditions of the problem, then you make the conversion of pascals to kilopascals at the end of the solution of the problem. The fact is that pascals are a system unit and if the other parameters are indicated in SI units, then the result will be in pascals (of course, if pressure was determined).

In order to correctly solve problems, it is necessary to ensure that the units of measurement of quantities correspond to the whole system. Usually, an international system of measurements is used to solve mathematical and physical problems. If the values are given in other systems, they must be converted to international (SI).

You will need

– tables of multiples and submultiples;
- calculator.

Instruction

1. One of the main quantities that are measured in applied sciences is length. Usually it was measured in steps, elbows, transitions, versts, etc. Today, the standard unit of length is 1 meter. The fractional values from it are centimeters, millimeters, etc. For example, in order to convert centimeters to meters, you need to divide them by 100. If the length is measured in kilometers, convert it to meters by multiplying by 1000. To convert national units of length, use the appropriate indicators.

2. Time is measured in seconds. Other famous time units are minutes and hours. To convert minutes to seconds, multiply them by 60. Converting hours to seconds is done by multiplying by 3600. Let's say, if the time during which the event happened is 3 hours and 17 minutes, then convert it to seconds like this: 3? 3600 + 17? 60=11820 s.

3. Speed, as a derivative quantity, is measured in meters per second. Another famous unit of measurement is kilometers per hour. To convert the speed to m/s, multiply it by 1000 and divide by 3600. Let's say if the speed of a cyclist is 18 km/h, then this value in m/s will be equal to 18×1000/3600=5 m/s.

4. Area and volume are measured respectively in m? them?. When translating, observe the multiplicity of values. Say, in order to translate cm? in m?, divide their number not by 100, but by 100? = 1000000.

5. Temperature is usually measured in degrees Celsius. But in most problems it needs to be converted to absolute values (Kelvins). To do this, add the number 273 to the temperature in degrees Celsius.

6. The unit of measurement for pressure in the international system is Pascal. But often in technology, a unit of measurement of 1 atmosphere is used. For translation, use the ratio 1 atm.? 101000 Pa.

7. Power in the international system is measured in watts. Another well-known unit of measure, in particular, used for collation of an automobile engine is horsepower. To convert values, use the ratio 1 horsepower = 735 watts. Let's say, if the motor of a car has a power of 86 horsepower, then in watts it is equal to 86 × 735 = 63210 watts or 63.21 kilowatts.

Pascals measure the pressure that a force F acts on a surface whose area is S. Conversely, 1 Pascal (1 Pa) is the magnitude of the effect of a force of 1 Newton (1 N) on an area of 1 m?. But there are other units of pressure, one of which is megapascal. Because what to convert megapascals to pascals?

You will need

Calculator.

Instruction

1. In advance, you need to deal with those units of pressure that are between pascal and megapascal. There are 1000 Kilopascals (KPa), 10000 Hectopascals (GPa), 1000000 Decapascals (DaPa) and 10000000 Pascals in 1 megapascal (MPa). This means that in order to convert pascal to megapascal, it is necessary to build 10 Pa to the power of “6” or multiply 1 Pa by 10 seven times.

2. In the first step, it became clear what to do in order to make a direct transition from small pressure units to larger ones. Now, in order to do the opposite, you need to multiply the existing value in megapascals by 10 seven times. On the contrary, 1 MPa = 10,000,000 Pa.

3. For greater simplicity and clarity, it is possible to see an example: in an industrial propane cylinder, the pressure is 9.4 MPa. How many Pascals will be the same pressure? The solution of this problem requires the use of the above method: 9.4 MPa * 10000000 = 94000000 Pa. (94 million Pascals). Result: in an industrial cylinder, the propane pressure on its walls is 94,000,000 Pa.

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Note!
It is worth noting that much more often not the classical unit of pressure is used, but the so-called “atmosphere” (atm). 1 atm = 0.1 MPa and 1 MPa = 10 atm. For the example considered above, another result will also be objective: the propane pressure of the cylinder wall is 94 atm. It is also acceptable to use other units, such as: - 1 bar \u003d 100000 Pa - 1 mm Hg (millimeter of mercury) \u003d 133.332 Pa - 1 m of water. Art. (meter of water column) = 9806.65 Pa

Useful advice
Pressure is denoted by the letter P. Based on the information given above, the formula for finding pressure will look like this: P \u003d F / S, where F is the force on the area S. Pascal is the unit of measurement used in the SI system. In the CGS system (“Centimeter-Gram-Second”), pressure is measured in g / (cm * s?).

The density of mercury, at room temperature and typical atmospheric pressure, is 13,534 kilograms per cubic meter, or 13.534 grams per cubic centimeter. Mercury is the densest liquid known to date. It is 13.56 times denser than water.

Density and its units

Density or bulk density of the mass of a substance is the mass of this substance per unit volume. More often than not, the Greek letter rho - ? is used to designate it. Mathematically, density is defined as the ratio of mass to volume. In the International System of Units (SI), density is measured in kilograms per cubic meter. That is, one cubic meter of mercury weighs 13 and a half tons. In the previous SI system, CGS (centimeter-gram-second), it was measured in grams per cubic centimeter. In the traditional systems of units still in use today in the United States and inherited from the British Imperial System of Units, density may be given in ounces per cubic inch, pounds per cubic inch, pounds per cubic foot, pounds per cubic yard, pounds per gallon, pounds per bushel and others. To facilitate the comparison of density between different systems of units, it is sometimes indicated as a dimensionless quantity - relative density. Relative density - the ratio of the density of a substance to a certain standard, as usual, to the density of water. Thus, a relative density less than one means that the substance floats in water. Substances with a density less than 13.56 will float in mercury. As you can see in the picture, a coin made of a metal alloy with a relative density of 7.6 floats in a container of mercury. The density depends on temperature and pressure. As the pressure increases, the volume of the material decreases and, consequently, the density increases. As the temperature increases, the volume of a substance increases and the density decreases.

Some properties of mercury

The property of mercury to change density when heated has found use in thermometers. As the temperature rises, mercury expands more evenly than other liquids. Mercury thermometers are allowed to take measurements in a wide temperature range: from -38.9 degrees, when mercury freezes, to 356.7 degrees, when mercury boils. The upper limit of measurements is easy to raise by increasing pressure. In a medical thermometer, due to the high density of mercury, the temperature remains exactly at the same level as it was in the patient's armpit or in another place where the measurement was taken. When the mercury tank of the thermometer is cooled, part of the mercury still remains in the capillary. They drive the mercury back into the tank by shaking the thermometer sharply, informing the heavy mercury column of an acceleration many times greater than the acceleration of free flight. True, now in medical institutions in a number of countries they are zealous to abandon mercury thermometers. The reason is the toxicity of mercury. Getting into the lungs, mercury vapor stays there for a long time and poisons every organism. The typical work of the central nervous system and kidneys is disrupted.

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Note!
Atmospheric pressure is measured with the support of a barometer, in which just a column of mercury is present. In addition to these 2 units, there are other units: bars, atmospheres, mm of water column, etc. 1 mm of mercury is also called torr.