Note: You are currently viewing documentation for Moodle 3.3. Up-to-date documentation for the latest stable version of Moodle is probably available here: Systems of units.

Systems of units: Difference between revisions

From MoodleDocs
No edit summary
 
(4 intermediate revisions by the same user not shown)
Line 1: Line 1:
[https://docs.moodle.org/33/en/Formulas_question_type < Formulas question type]
<div style="background:#d9edf7;color:#3a87ad;0px;padding:8px;border:1px solid #bce8f1;border-radius:4px;margin:0;">
 
<p style="margin:2px 8px;">
 
This page has been moved to  '''[[Formulas:_Systems_of_units|Formulas: Systems of units]]'''  ←''click the link''
==Systems of units==
</p>
 
The '''International System of Units''' (SI, from the French ''Système international (d'unités)'') is the most widely used system of measurement. It has now been adopted accross the world, except in Liberia, Myanmar and the United States. The US is the only industrialized nation that does not mainly use the SI in its commercial and standards activities<sup>Wikipedia, International System of Units</sup>. [https://www.bipm.org/en/publications/si-brochure/ The SI is available here, free of charge. (The English version follows the French version.)]
 
In the SI, units are classified as follows (with reference to the table in the SI):
 
<div style="border:1px solid #bce8f1;border-radius:4px;padding:0px 15px 0px;">
* Base units (Table 1)
* Coherent derived units (Table 2)
* Coherent derived units with special names and symbols (Table 3)
Note that coherent derived units can include coherent derived units with special names and symbols (Table 4)
* Non-SI units accepted for use with the SI (Table 6)
* Non-SI units whose values in SI units must be obtained experimentally (Table 7)
* Other non-SI units (Table 8)
* Non-SI units associated with the CGS and the CGS-Gaussian system of units (Table 9)
* Other non-SI units not recommended of use (including the British imperial system and the United States customary system of units)
</div>
</div>
 
''Do not delete this page.''
Conversion factors for the later units are available from the US National Institute of Standards and Technology (NIST):
* [https://www.nist.gov/physical-measurement-laboratory/nist-guide-si-appendix-b8 listed alphabetically]
* [https://www.nist.gov/pml/nist-guide-si-appendix-b9-factors-units-listed-kind-quantity-or-field-science listed by kind of quantity or field of science]
 
===SI base units===
There are seven base units in the SI:
 
{| class="nicetable"
|-
! Name
! Symbol
! Formulas question<br>input
|-
| metre
| m
| m
|-
| kilogram
| kg
| kg
|-
| second
| s
| s
|-
| ampere
| A
| A
|-
| kelvin
| K
| K
|-
| mole
| mol
| mol
|-
| candela
| cd
| cd
|}
 
===Coherent derived units===
Coherent derived units are products of powers of base units, without a numerical factor. Some examples of coherent derived units are as follows:
 
{| class="nicetable"
|-
! Name
! Symbol
! colspan="2" | Formulas question<br><span style="font-weight:normal">Input from either column is acceptable</span>
|-
| square meter
| m<sup>2</sup>
| m^2
|
|-
| cubic meter
| m<sup>3</sup>
| m^2
|
|-
| meter per second
| m/s
| m/s
| m s^(-1)
|-
| meter per second squared
| m/s<sup>2</sup>
| m/s^2
| m s^(-2)
|-
| reciprocal metre
| m<sup>-1</sup>
| m^(-1)
|
|-
| kilogram per cubic metre
| kg/m<sup>3</sup>
| kg/m^3
| kg m^(-3)
|-
| kilogram per square metre
| kg/m<sup>2</sup>
| kg/m^2
| kg m^(-2)
|-
| cubic metre per kilogram
| m<sup>3</sup>/kg
| m^3/kg
| m^3 kg^(-1)
|-
| ampere per square metre
| A/m<sup>2</sup>
| A/m^2
| A m^(-2)
|-
| etc.
|
|
|
|}
 
===Coherent derived units with special names and symbols===
Some coherent derived units have special names and symbols:
 
{| class="nicetable"
|-
! Name
! Symbol
! colspan="3" | Formulas question<br><span style="font-weight:normal">Input from either column is acceptable</span>
|-
| radian
| rad
| rad
|
|
|-
| steradian
| sr
| sr
|
|
|-
| hertz
| Hz
| Hz
|
| s^(-1)
|-
| newton
| N
| N
|
| m kg s^(-2)
|-
| pascal
| Pa
| Pa
| N/m^2
| m^(-1) kg s^(-2)
|-
| joule
| J
| J
| N m
| m^2 kg s^(-2)
|-
| watt
| W
| W
| J/s
| m^2 kg s^(-3)
|-
| coulomb
| C
| C
|
| s A
|-
| volt
| V
| V
| W/A
| m^2 kg s^(-3) A^(-1)
|-
| farad
| F
| F
|
|
|-
| ohm
| Ω
|
|
|
|-
| siemens
| S
| S
|
|
|-
| weber
| Wb
| Wb
|
|
|-
| tesla
| T
| T
|
|
|-
| henry
| H
| H
|
|
|-
| degree Celcius
| ℃
| ℃
|
|
|-
| lumen
| lm
| lm
|
|
|-
| lux
| lx
| lx
|
|
|-
| becquerel
| Bq
|
|
|
|-
| gray
| Gy
|
|
|
|-
| sievert
| Sv
|
|
|
|-
| katal
| kat
|
|
|
|}
 
The base and coherent derived units of the SI form a coherent set, designated the set of coherent SI units. There are also units outside the SI.
 
===Non-SI units accepted for use with the SI===
Non-SI units accepted for use with the SI are:
 
{| class="nicetable"
|-
! Name
! Symbol
! Formulas question<br>input
|-
| minute
| min
| min
|-
| hour
| h
| h
|-
| day
| d
| d
|-
| degree (plan angle)
| °
|
|-
| minute (plan angle)
| ′
|
|-
| second (plan angle)
| ″
|
|-
| hectare
| ha
| ha
|-
| litre
| L, l
| L or l
|-
| tonne
| t
| t
|}
 
==SI Prefixes==
The '''SI''' and '''Formulas question''' prefixes are given in the table below. The only difference between the two systems is that the prefix micro is written μ in the '''SI''' but entered as u in the '''Formulas question'''.
 
{| class="nicetable"
|-
! Factor
! Name
! SI symbol
! Formulas question<br>input
!         
! Factor
! Name
! SI symbol
! Formulas question<br>input
|-
| 10<sup>1</sup>
| deca
| da
| da
|
| 10<sup>-1</sup>
| deci
| d
| d
|-
| 10<sup>2</sup>
| hecto
| h
| h
|
| 10<sup>-2</sup>
| centi
| c
| c
|-
| 10<sup>3</sup>
| kilo
| k
| k
|
| 10<sup>-3</sup>
| milli
| m
| m
|-
| 10<sup>6</sup>
| mega
| M
| M
|
| 10<sup>-6</sup>
| micro
| μ
| u
|-
| 10<sup>9</sup>
| giga
| G
| G
|
| 10<sup>-9</sup>
| nano
| n
| n
|-
| 10<sup>12</sup>
| tera
| T
| T
|
| 10<sup>-12</sup>
| pico
| p
| p
|-
| 10<sup>15</sup>
| peta
| P
| P
|
| 10<sup>-15</sup>
| femto
| f
| f
|-
| 10<sup>18</sup>
| exa
| E
| E
|
| 10<sup>-18</sup>
| atto
| a
| a
|-
| 10<sup>21</sup>
| zetta
| Z
| Z
|
| 10<sup>-21</sup>
| zepto
| z
| z
|-
| 10<sup>24</sup>
| yotta
| Y
| Y
|
| 10<sup>-24</sup>
| yocto
| y
| y
|}
 
----
 
==Formulas question system of units==
The system of units of the '''Formulas question''' type complies with the '''SI'''. '''Formulas question''' units can be any of all the units mentioned above, i.e. SI units and non-SI units.
 
<div style="background-color:#d3ffd3;
            border:1px solid #abdaac;
            color:#4f691a;
            padding:5px 15px 10px;
            margin: 15px 0 20px;
            ">'''Formulas question''' units can be either single or combined.
</div>
 
{| class="nicetable"
|-
! rowspan="2" | Formulas question<br>unit
! rowspan="2" |Type
! colspan="3" | <div style="text-align:center">Examples</div>
|-
! Name of unit
! SI symbol
! Formulas question<br>input
|-
| rowspan="21" | Single (i.e. individual) unit
| rowspan="3" | SI base unit
| meter
| m
|m
|-
| kilogram
| kg
| kg
|-
| second
| s
| s
|-
| rowspan="3" | Coherent derived SI units with special names and symbols
| hertz
| Hz
| Hz
|-
| newton
| N
| N
|-
| pascal
| Pa
| Pa
|-
| rowspan="3" | Non-SI units accepted for use with the SI
| minute
| min
| min
|-
| hour
| h
| h
|-
| day
| d
| d
|-
| rowspan="3" | Non-SI units whose values in SI units must be obtained experimentally
| electronvolt
| eV
| eV
|-
| dalton
| Da
| Da
|-
| unified atomic mass unit
| u
| u
|-
| rowspan="3" | Other non-SI units
| bar
| bar
| bar
|-
| millimetre of mercury
| mmHg
| mmHg
|-
| ångström
| Å
| Å (Ascii 143)
|-
| rowspan="3" | Non-SI units associated with the CGS and the CGS-Gaussian system of units
| erg
| erg
| erg
|-
| dyne
| dyn
| dyn
|-
| poise
| P
| P
|-
| rowspan="3" | Other non-SI units not recommended for use
| barrel of oil
| bbl
| bbl
|-
| inch
| inch
| in
|-
| foot
| ft
| ft
|-
| rowspan="13" | Combined unit (any combination of single units)
| rowspan="13" | All types
| square meter
| m<sup>2</sup>
| m^2
|-
| meter per second
| m/s
| m/s
|-
| meter per second squared
| m/s<sup>2</sup>
| m/s^2
|-
| hertz expressed in terms of SI base units
| s<sup>-1</sup>
| s^(-1)
|-
| newton expressed in terms of SI base units
| m kg s<sup>-2</sup>
| m kg s^(-2)
|-
| pascal expressed in terms of SI base units
| m<sup>-1</sup> kg s<sup>-2</sup>
| m^(-1) kg s^(-2)
|-
| pascal second
| Pa s
| Pa s
|-
| radian per second squared
| rad/s<sup>2</sup>
| rad/s^2
|-
| watt per square metre steradian
| W/(m<sup>2</sup> sr)
| W/(m^2 sr)
|-
| poise expressed in terms of CGS units
| dyn s cm<sup>-2</sup>
| dyn s cm^(-2)
|-
| foot pound
| ft lb
| ft lb
|-
| pound per inch squared
| lb/in<sup>2</sup>
| lb/in^2
|-
| Btu per hour
| Btu/h
| Btu/h
|}

Latest revision as of 04:50, 31 December 2017

This page has been moved to  Formulas: Systems of units  ←click the link

Do not delete this page.