Name: si units and metric prefixes
Uploaded: 2023-09-22T11:49:19.000Z
Duration: 1 min 29 s
Channel: JoVE

K12 Standards

Texas Essential Knowledge and Skills

High School

Specialised Topic in Science

112.51.c.1.

112.51.c.1.E.

International System of Units

Międzynarodowy układ jednostek miar jest powszechnie akceptowany na całym świecie, a jednostkami podstawowymi są metry, kilogramy i sekundy. Jednostki te są bezwzględne, a ich wartość nie zmienia się w zależności od lokalizacji.
Prefiksy służą do definiowania większych i mniejszych ilości. Milli, mikro i nano są używane do oznaczania mniejszych ilości, podczas gdy kilo, mega i giga są używane do oznaczania większych ilości.
Jednak wśród jednostek podstawowych kilogram jest jedyną jednostką bazową zdefiniowaną za pomocą prefiksu.
Podczas wyrażania jednostek i przedrostków należy przestrzegać kilku zasad. Po pierwsze, kropki służą do różnicowania jednostek w jednostkach złożonych.
Po drugie, w mianowniku unika się przedrostka i jest on wyrażony tylko w liczniku jednostki złożonej.
Po trzecie, potęga wykładnicza jednostki z prefiksem odnosi się do przedrostka i jego jednostki, a na końcu wynik jest reprezentowany za pomocą pojedynczego prefiksu.
W przeciwieństwie do systemu metrycznego, SI nie używa wielokrotności deka lub centi.

<ol>
	<li>Hibbeler, R.C. (2016). Mechanika inżynierska \u2012 Statyka i dynamika. Hoboken, New Jersey: Pearson Prentice Hall. str. 9\u201210</li>
	<li>Piwo, F.P.; Johnston, E.R.; Mazurek, D.F.; Cromwell, PJ i Self, BP (2019). Mechanika wektorowa dla inżynierów \u2012 Statyka i dynamika. Nowy Jork: McGraw-Hill. str. 5 i 7</li>
	<li>Meriam, J.L.; Kraige, L.G. i Bolton, J.N. (2020). Mechanika inżynierska \u2012 Statyka. Hoboken, New Jersey: John Wiley. str. 7 i 8</li>
</ol>

międzynarodowy układ jednostek miar

Międzynarodowy Układ Jednostek Miar, znany również jako system SI, jest uniwersalnie akceptowanym systemem miar, uznawanym i stosowanym na całym świecie. System SI opiera się na siedmiu podstawowych jednostkach uważanych za absolutne, których wartości nie zmieniają się w zależności od lokalizacji. Trzy z nich to metr, kilogram i sekunda.

Przedrostki są używane do określania zarówno większych, jak i mniejszych ilości w systemie SI. Na przykład przedrostki mili, mikro i nano określają mniejsze ilości, podczas gdy kilo, mega i giga są używane do określania większych ilości. Kilogram jest jedyną podstawową jednostką zdefiniowaną z przedrostkiem wśród jednostek podstawowych systemu SI.

Podczas wyrażania jednostek i przedrostków należy przestrzegać kilku zasad. Po pierwsze, kropki są używane do odróżniania jednostek w składanych jednostkach. Po drugie, przedrostek jest unikany w mianowniku i wyrażany tylko w liczniku składanej jednostki. Po trzecie, potęga na jednostce z przedrostkiem odnosi się do przedrostka i jego jednostki. Wyniki są reprezentowane za pomocą jednego przedrostka.

Warto zauważyć, że w przeciwieństwie do systemu metrycznego, system SI nie używa krotności deka ani centy. Przedrostki systemu SI opierają się na potęgach dziesiątki, przy czym jednostka podstawowa nie ma przedrostka. Jednostki SI mają na celu uproszczenie i standaryzację pomiarów naukowych poprzez wykorzystanie uniwersalnego systemu.

Jednym z głównych powodów, dla których na całym świecie używa się systemu SI, jest jego dokładność i precyzja w pomiarach. Nawet najmniejsze i największe ilości można dokładnie określić za pomocą jednostek podstawowych i przedrostków.

Podstawową jednostką długości w systemie SI jest metr, zdefiniowany jako odległość, jaką przebywa światło w próżni w określonym czasie. Inne jednostki miary, takie jak centymetr, kilometr i milimetr, mogą być wyliczone z metra za pomocą systemu przedrostków.

Podstawową jednostką masy w systemie SI jest kilogram, zdefiniowany jako masa zestawu obiektów podstawowych znanych jako Międzynarodowy Prototyp Kilograma. Inne jednostki masy, takie jak gram i miligram, mogą być wyliczone z kilograma za pomocą systemu przedrostków.

Podstawową jednostką czasu w systemie SI jest sekunda, zdefiniowana jako czas trwania 9 192 631 770 cykli promieniowania związanego z konkretnym przejściem między poziomami energetycznymi atomu cezu-133. Z sekundy można wyliczyć inne jednostki czasu, takie jak minuta i godzina, za pomocą systemu przedrostków.

Oprócz tych jednostek, cztery kolejne są zdefiniowane jako fundamentalne jednostki miary. Są to amper, kelwin, mol i kandela.

Międzynarodowy Układ Jednostek Miar

Międzynarodowy Układ Jednostek Miar, znany jako układ SI, jest powszechnie akceptowanym systemem miar, uznawanym i stosowanym na całym świecie. Układ SI jest ...

Education

JoVE Core

Mechanical Engineering

Inżynieria mechaniczna

Unit 1

Jednostka 1

An Introduction to Statics

Wstęp do statyki

KEY TERMS AND CONCEPTS

Kluczowe terminy i pojęcia

si units and metric prefixes

SI units and metric prefixes provide a standard way to measure size, mass, and time. The International System of Units, or SI system, is used worldwide because it gives scientists a common language for measurement. Its values do not change with location, which helps keep results consistent.

The SI system is built on three base units: meter, kilogram, and second. These are the core units for length, mass, and time. The kilogram is the only base unit that already includes a prefix.

Prefixes make it easy to express very large or very small values. Milli, micro, and nano represent smaller quantities. Kilo, mega, and giga represent larger quantities. SI prefixes are based on powers of ten, and the base unit has no prefix.

Several rules apply when writing SI units. Dots are used to separate units in composite units. A prefix should not appear in the denominator, only in the numerator. If a unit with a prefix is raised to a power, the power applies to both the prefix and the unit. The final answer should use just one prefix. Unlike the metric system, SI does not use deca or centi.

SI units help simplify and standardize scientific measurements. They also improve accuracy and precision, even for very small or very large quantities. The meter is defined as the distance light travels in a vacuum during a specific time frame. Other length units, such as centimeter, kilometer, and millimeter, come from the meter.

The kilogram is the SI base unit of mass. It was defined as the mass of a set of foundational objects called the International Prototype of the Kilogram. Grams and milligrams are derived from the kilogram. The second is the SI base unit of time and is defined by 9,192,631,770 cycles of radiation from a specific transition in cesium-133. Minutes and hours can be derived from the second. Four more fundamental units are also part of SI: ampere, Kelvin, mole, and candela.

SI Units and Metric Prefixes

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SI units and metric prefixes provide a standard way to measure size, mass, and time. The International System of Units, or SI system, is used worldwide because it gives scientists a common language for measurement. Its values do not change with location, which helps keep results consistent. The SI system is built on three base units: meter, kilogram, and second. These are the core units for length, mass, and time. The kilogram is the only base unit that already includes a prefix. Prefixes...

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Learn how SI units use meters, kilograms, seconds, and metric prefixes to measure length, mass, and time with accuracy and consistency.

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Physics

PHYS.1

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112.51.c.1.C.

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112.51.c.1.D.

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112.51.c.1.F.

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112.51.c.1.G.

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112.51.c.1.H.

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112.51.c.2.A.

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112.51.c.2.B.

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SI Units and Metric Prefixes

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