Incazelo yamayunithi aphesheya
Uhlelo Lwezinyunithi
Isibonelo, uma ulinganisa ubude bakho bese ububika njengo-100, umphumela awunamsebenzi. Ngokufanayo, uma ulinganisa isisindo somzimba wakho bese ububika njengo-20, umphumela nawo awunamsebenzi futhi awuqondakali kwabanye. Ngaphandle kokubika inombolo noma isibalo esithile, isilinganiso kumele sihambisane neyunithi. Uma uthi ukuphakama kwakho kungama-fathom ama-2, khona-ke u-2 yinombolo yokulinganisa kanti ama-fathom yiwo amayunithi owasebenzisayo. Abantu abajwayele ukusebenzisa ama-fathom bayaqonda lesi silinganiso. Noma, uma ulinganisa ubude betafula olisebenzisa ekilasini bese ububika njengobubanzi obu-5, umphumela uyaqondakala kwabanye abasebenzise ububanzi njengeyunithi.
Kunezinhlobo eziningi zamayunithi asetshenziswa emhlabeni, kuye ngamasiko endawo. Isibonelo, iyunithi yobude eyake yasetshenziswa eNgilandi yayiyiyadi, noma iyunithi yobude eyake yasetshenziswa eFrance yayiyinyawo, noma iyunithi yobude eyake yasetshenziswa eGibhithe lasendulo yayiyingalo. Uma ujwayele ukusebenzisa iyunithi yespan noma yefathom bese ufunda isihloko esithi intaba ephakeme kunazo zonke emhlabeni ingamamitha ayi-10.000, isibonelo, uzodideka futhi ungabi nasithombe esicacile sokuphakama kwentaba.
Incazelo ye-span eyodwa ibanga eliphakathi kwesihloko sesithupha nesihloko somunwe wokukhomba lapho weluliwe. I-fathom eyodwa ibanga eliphakathi kwesihloko somunwe ophakathi nesihloko sengalo lapho isandla seluliwe. I-yard eyodwa ibanga eliphakathi kwesihloko sekhala lenkosi yaseNgilandi (1120 AD) nesihloko sengalo yakhe eyeluliwe. I-1 foot ubude bonyawo lweNkosi uLouis XIV, iNkosi yaseFrance. Ingalo eyodwa ibanga eliphakathi kwengalo nesihloko somunwe ophakathi lapho weluliwe. I-span eyodwa noma i-fathom eyodwa noma i-yard eyodwa noma i-1 foot, iyisibonelo seyunithi eyisisekelo yobude. Uma ubude betafula = ama-span ama-5 khona-ke ubude betafula buphindwe kahlanu kunobude bomuntu olilinganisayo. Kulokhu, i-span yomuntu isetshenziswa njengeyunithi ejwayelekile yokulinganisa ubude.
Kubalulekile ukuqonda ukuthi umzimba womuntu uyakhula, ngakho-ke ububanzi, i-fathom, ingalo, unyawo, noma igceke kungashintsha. Ngokufanayo, ukusebenzisa amayunithi ahlukene kungabangela ukudideka kulabo abangawazi. Ukuze kutholakale izilinganiso ezinembile nezithembekile, kudingeka inani eliyisisekelo elijwayelekile elingaguquki futhi eliphindaphindwayo ukuze lisetshenziswe emhlabeni jikelele.
Uhlelo Lwamazwe Ngamazwe Lwamayunithi
Uhlelo lwamayunithi olusetshenziswa ososayensi nonjiniyela emhlabeni wonke ekuqaleni lwalubizwa ngokuthi uhlelo lwe-metric. Kusukela ngo-1960, luye lwabizwa ngokuthi uhlelo lwamazwe ngamazwe, noma i-SI ngamafuphi. Amayunithi e-SI e- inani eliyinhloko kungabonakala etafuleni lezinto eziyisisekelo.
Iyunithi inani elitholiwe ingachazwa ngamayunithi amabili noma ngaphezulu okulinganisa ayisisekelo; isibonelo, iyunithi yendawo ingu-m2, iyunithi yesivinini ingu-m/s, iyunithi yobuningi ingu-kg/m3, iyunithi yokusheshisa ingu-m/s2, iyunithi yamandla yi-kg m/s2, amayunithi omsebenzi namandla angama-kg m2/s2, iyunithi yamandla yi-kg m2/s3.
Amanye amanani atholakalayo amayunithi awo aqukethe amayunithi ayisisekelo amaningana anikezwa amagama akhethekile; isibonelo, iyunithi yamandla kg m/s2 okubizwa ngokuthi iNewton (N), iyunithi yomsebenzi kanye namandla kg m2/s2 okubizwa ngokuthi iJoule (J), iyunithi yamandla kg m2/s3 ebizwa ngokuthi uWatt (W).
Isiqalo Seyunithi
Singachaza amayunithi e-SI njengamakhulu noma amancane sisebenzisa iziqalo zamayunithi. Iziqalo zamayunithi ziyiziphindaphindo eziyi-10 zeyunithi eyisisekelo. Iziqalo zamayunithi zivame ukungezwa kumayunithi e-SI ukudala amayunithi amasha.
Izibonelo zeziqalo zamayunithi ezingezwe kumayunithi ayisisekelo
Izibonelo zeziqalo zamayunithi ezingezwe kumayunithi asuselwe kuwo:
1 kW (kilowatt) = 103 W = 1000 W —> W = Watt (Iyunithi yamandla)
1 MW (megawatt) = 106 W = 1000.000 W —> W = Watt (Iyunithi yamandla)
1 MV (megavolt) = 106 V = 1000.000 V —> V = Volt (Iyunithi yevolthi kagesi)
1 nC (nanocoulomb) = 1 nC = 10-9 C —> C = Coulomb (Iyunithi yamandla kagesi)
1 kPa (kilopascal) = 103 Pa —> Pa = Pascal (Iyunithi yokucindezela)
1 GHz (gigahertz) = 109 I-Hz —> Hz = i-Hertz (Iyunithi yemvamisa)
