# Kevreyth Keswlasek Unsesow

Furv arnowydh an system metrik a vusur yw an **Kevreyth Keswlasek Unsesow**, (Frynkek - Le Système international d'unités}}; Sowsnek - International System of Units) selys war seyth unses elvennek ha devnydh an niver deg (10).

Ottomma an system musur gwella gerys y'n bys, po yn diwysyans, po adhysk po godhonieth. Kevys yw ynwedh, unsesow moy degemerys warbarth ha rol an SI.

Gwithys yw komendyans sodhogel dhe'n Kevreyth war wiasva NIST, ow komprehendya golinyans a gesberthynyans an unsesow an eyl dh'y gila. A-is yma rol a'n unsesow elvennel (kevys yw rol leun yn derivans (CODATA) a-dro dhe re erel kepar ha tooth golow.

==An seyth unses elvennel==seyth chif klass, ow settya rag-gorransow a-rag an henwyn. Pubonan a'n unsesow elvennel a sew yw sortow dyffrans a vusuransow. Pub unses aral a dheu dhyworth an seyth ma.

An seyth unses elvennel SI| Hanow | Arwodh an Unses | An pyth yw musurys | Arwodh |
| --- | --- | --- | --- |
| meter | **m** | hys | *l (lytheren vyghan)* |
| kilogram | **kg** | gronnedh | *m* |
| eylen | **s** | termyn | *t* |
| amper | **A** | fros tredan | *I (i: lytheren veur)* |
| kelvin | **K** | tempredh | *T* |
| kandela | **cd** | krefter golow | *Iv (*i *meur gans tanskrifans* v*)* |
| mol | **mole** | myns a dhevnydh | *n* |

## Rag-gorrans

Rag-gorrans savonys dhe ri a-rag an Unsesow| Liessommen | Hanow |  | deca- | hecto- | kilo- | mega- | giga- | tera- | peta- | exa- | zetta- | yotta- |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Arwodh |  | da | h | k | M | G | T | P | E | Z | Y |
| Faktor | 100 | 101 | 102 | 103 | 106 | 109 | 1012 | 1015 | 1018 | 1021 | 1024 |
|   |
| Isklass | Hanow |  | deci- | centi- | milli- | micro- | nano- | pico- | femto- | atto- | zepto- | yocto- |
| Arwodh |  | d | c | m | μ | n | p | f | a | z | y |
| Faktor | 100 | 10−1 | 10−2 | 10−3 | 10−6 | 10−9 | 10−12 | 10−15 | 10−18 | 10−21 | 10−24 |

## Nebes unsesow SI rag Fysegieth

An lythyerennek (Fysegieth)| Pyth y musurys | An ger Sowsnek | SArwodh | Unses savonek | Furvel |
| --- | --- | --- | --- | --- |
| Dyffrans potensyal | *Potential difference* | **V** | volt, V | V = I.R |
| Fros | *Current* | **I** | amper, A | I = V/R |
| Sprallansedh tredanel | *electric resistance* | **R** | ohm, Ω | R = V/I |
| Dynedh tredanel | *electric inductance* | **L** | henry, H | H = Ώ.s |
| Dalghasedh tredanel | *electric capacitance* | **C** | farad, F | F = s/Ώ |
| Kargedh | *Charge* | **Q** | coulomb, C | Q = I.t |
| Radyovewekter ha breynans radyovewek | *Radioactivity* a *Radioactive decay* | **Bq** | becquerel | 1/s po A= -λN |
| Gallosedh | *Power* | **P** | watt, W | P = V.I po P = I2.R |
| Nerth | *Energy* | **E** | joule, J | E = Q.V po V = E/Q |
| Termyn | *Time* | **t** | Eylen, s | E = F.I po P.t |
| Forsedh | *Force* | **F** | newton, N | F = m.a |
| Gronnedh | *Mass* | **m** | kilogram, kg | F = m.a |
| Poos | *Weight* neu *force* | **W** | newton, N | W = m.g |
| Dosedh | *Density* | **D** | kg/m3, kg/m3 | D = m/V |
| Torghedh | *Moment of force* po *torque* | **M** | newton-meter, Nm | IM = F.l |
| Skavder po tooth | *Speed* neu *velocity* | **v** | meter/eylen, m/s | v = p/t |
| Uskisheans | *Acceleration* | **a** | meter/eylen2, m/s2 | a = Δv/t po a = F/m |
| Gwaskedh | *Pressure* | **P** | Pascal, Pa (N/m2) | P = F/A |
| Arenebedh | *Area* | **A** | meter2, m2 | A=s2 (s = hys an tu) |
| Dalghedh | *Volume* | **V** | meter3, m3 | A=s3 (s = hys an tu) |
| Menowghder | *Frequency* | **f** po **ν** (**ν** = *nu* Grek) | hertz, Hz | f = 1/t (t = spys termyn) |
| Tonnhys | *Wavelength* | **λ** | meter, m | v = ν.λ (furvel ton) |
| Ober gwrys | *Work* po *heat* | **Wd** | joule, J | Wd = F.d |
| Nerth galladow | *Potential energy* | **EP** | joule, J | EP = m.g.Δh (h = ughelder) |
| Nerth kinetyk | *Kinetic energy* | **EC** | joule, J | EC= ½ m.v2 |

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