stanford-oval/wikipedia huggingface dataset:
Keracunan talium

| Keracunan talium |
| --- | --- |

Talium
Informasi umum
Spesialisasi: Kedokteran gawat darurat 
Talium dan senyawa-senyawanya sangat beracun. Bersentuhan dengan unsur ini saja sangat berbahaya, dan diperlukan ventilasi yang cukup saat sedang melelehkan logam ini. Banyak senyawa talium(I) yang dapat larut dengan mudah di dalam air dan dapat masuk ke dalam kulit. Paparan terhadap talium tidak boleh melebihi 0,1 mg per m2 untuk kulit dalam rata-rata waktu selama 8 jam. Talium juga diduga merupakan bahan karsinogen.
Salah satu alasan mengapa talium sangat beracun adalah karena ion talium(I) berlaku seperti kation-kation logam alkali, khususnya kalium (karena memiliki jari-jari ionik yang serupa). Maka dari itu, senyawa ini dapat masuk ke dalam tubuh seperti kalium. Di sisi lain, talium memiliki banyak perbedaan dengan logam alkali, sepertinya afinitasnya terhadap ligan sulfur yang tinggi. Maka dari itu, penggantian kalium atau natrium dengan talium mengakibatkan gangguan pada proses-proses biologis pada sel. Contohnya, talium dapat menyerang protein yang mengandung sulfur (seperti residu sisteina dan feredoksin).
Beberapa efek keracunan talium adalah rambut rontok (sehingga talium pernah digunakan untuk merontokkan bulu dan rambut sebelum bahayanya diketahui) dan kerusakan terhadap saraf periferal (korban dapat mengalami rasa seperti berjalan di atas batu bara panas), walaupun rambut rontok biasanya hanya terjadi jika dosisnya rendah; dalam dosis yang tinggi, talium akan membunuh korbannya sebelum rambutnya bisa rontok. Talium pernah dijadikan senjata pembunuh yang efektif sebelum penawarnya ditemukan ("Biru Prusia"). Bahkan talium pernah diberi julukan "racunnya peracun" karena talium tidak berwarna, tidak berbau, dan tidak memiliki rasa; racunnya berdampak secara perlahan, menyebabkan rasa sakit dan juga gejala-gejala lainnya yang sering disalahtafsirkan sebagai penyakit yang lain.
Talium pernah digunakan sebagai racun tikus dan semut, tetapi kini sudah dilarang penggunaannya di berbagai negara.
Catatan kaki

1 2  Thallium Toxicity di eMedicine
1 2  "Biology of Thallium". webelemnts. Diakses tanggal 2008-11-11.
↑  "A Homogenous Thallium Flux Assay for High Throughput Screen of Potassium Channels" (PDF). Diarsipkan dari versi asli (PDF) tanggal 2014-10-21. Diakses tanggal 2018-01-30.
↑  "Eliminating Thallium (poisoning)". Diarsipkan dari versi asli tanggal 2015-10-23. Diakses tanggal 2018-01-30.
↑  Blum, The Poisoner's Handbook, 256
↑  Douglas, K. T.; Bunni, M. A.; Baindur, S. R. (1990). "Thallium in biochemistry". International Journal of Biochemistry. 22 (5): 429–438. doi:10.1016/0020-711X(90)90254-Z.
↑  Amy Ellis Nutt & Sue Epstein, A 15-year-old case yields a timely clue in deadly thallium poisoning, The Star-Ledger, February 13, 2011
Daftar spesies Ribes

Daftar spesies Ribes ini menunjukkan banyak dari sekitar 200 spesies yang diterima dalam tanaman genus Ribes, genus tunggal dalam Saxifragales famili Grossulariaceae. Secara tradisional, ini telah dibagi menjadi sejumlah subgenera, seperti subgenus Ribes  (kismis) dan subgenus Grossularia (gooseberry).
Subgenus Ribes L. > Bagian Berisia Spach

Bagian ini terdiri dari kismis Alpen (Alpine currants), spesies dioecious yang didistribusikan melalui Eurasia.
| Flowers | Fruit | Scientific name | Distribution |
| --- | --- | --- | --- |
|  |  | Ribes acuminatum Wall. ex G.Don | India |
|  |  | Ribes armenum Pojark. | South Caucasus |
|  |  | Ribes alpinum L. – alpine currant | northern Europe from Finland and Norway south to the Alps and Pyrenees and Caucasus, Georgia |
|  |  | Ribes diacanthum Pall. – Siberian currant | (Russia, Mongolia, Korea, northeastern China (Heilongjiang, Jilin, Inner Mongolia) |
|  |  | Ribes giraldii Jancz. | China (E Gansu, Liaoning, Shaanxi, SW Shanxi.) |
|  |  | Ribes glabricalycinum L.T.Lu | China (Sichuan) |
|  |  | Ribes glabrifolium L.T.Lu | China (W Hubei, S Shaanxi) |
|  |  | Ribes glaciale Wallich – glacier currant | China (SE Gansu, Henan, W Hubei, Shaanxi, Sichuan, SE Xizang, NW Yunnan), Bhutan, N India, Kashmir, N Myanmar, Nepal, Sikkim |
|  |  | Ribes henryi Franch. | China (W. Sichuan, Hubei) |
|  |  | Ribes heterotrichum C.A.Mey. | Central Asia to Mongolia and N. Pakistan. |
|  |  | Ribes humile Jancz. | China (Sichuan) |
|  |  | Ribes hunanense Chang Y.Yang & C.J.Qi | China ( Guangxi, Hunan) |
|  |  | Ribes kialanum Jancz. | China (W. Sichuan, NW. Yunnan) |
|  |  | Ribes komarovii Pojark. | Russian Far East, northern and central China, North Korea |
|  |  | Ribes laurifolium Jancz. – evergreen currant | China (W. Sichuan, Guizhou, Yunnan) to Myanmar. |
|  |  | Ribes luridum Hook. & Thoms. – purple currant | Nepal to China (W. Sichuan, NW. Yunnan) |
|  |  | Ribes maximowiczii Batal. – common Korean currant | China (Heilongjiang, Jilin, E Liaoning),Japan, Korea, Russia |
|  |  | Ribes orientale Desf. – Siberian currant | China (W Sichuan, Xizang, NW Yunnan),Bhutan, India, Kashmir, Nepal, Russia; SW Asia, SE Europe |
|  |  | Ribes saxatile Pall. | China (Xinjiang), Russia |
|  |  | Ribes takare D.Don | China, Bhutan, N India, Kashmir, Myanmar, Nepal, Sikkim |
|  |  | Ribes tianquanense S.H.Yu & J.M.Xu | China (Sichuan) |
|  |  | Ribes pseudofasciculatum K.S.Hao | China (Xizhang, Sichuan, Qinghai) |
|  |  | Ribes pulchellum Turcz. | S. Siberia to N. China. |
|  |  | Ribes rubrisepalum L.T.Lu | China (Gansu, S Shaanxi, W Sichuan, NW Yunnan.) |
|  |  | Ribes tenue Jancz. | China ( E Gansu, W Henan, W Hubei, NW Hunan, SW Shaanxi, Sichuan, Yunnan) |
|  |  | Ribes vilmorinii Jancz. | China (Hebei, W Sichuan, NW Yunnan.) |
|  |  | Ribes xizangense L.T.Lu | China (Xizang) |
Subgenus Ribes L. > Section Calobotrya (Spach) Jancz.

Bagian ini terdiri dari spesies Amerika Utara yang biasa dikenal sebagai kismis hias.
| Flowers | Fruit | Scientific name | Distribution |
| --- | --- | --- | --- |
|  |  | Ribes brandegeei Eastw. | Mexico |
|  |  | Ribes canthariforme Wiggins – Moreno currant | California |
|  |  | Ribes cereum Douglas – Squaw currant, wax currant, white field currant, whiskey currant | British Columbia, Alberta, and much of the western United States, from Washington, Oregon, and California east as far as the western Dakotas and the Oklahoma Panhandle |
|  |  | Ribes ceriferum Coville & Rose | Mexico (Durango and Chihuahua) |
|  |  | Ribes ciliatum Humb. & Bonpl. | Mexico |
|  |  | Ribes dugesii Greenm.  | Mexico |
|  |  | Ribes indecorum Eastw. – white-flowered currant | Santa Barbara County in California south into northern Baja California. |
|  |  | Ribes malvaceum Sm. – Chaparral currant | California and northern Baja California |
|  |  | Ribes mescalerium Coville – Mescalero currant | southeastern New Mexico, western Texas, and the Mexican State of Chihuahua. |
|  |  | Ribes neglectum Rose | Mexico |
|  |  | Ribes nelsonii Coville & Rose | Mexico (Sonora, Chihuahua) |
|  |  | Ribes nevadense Kellogg – Sierra currant, Jaeger's currant, Nevada currant | California, Nevada, Oregon |
|  |  | Ribes orizabae Rose | Mexico (Veracruz) |
|  |  | Ribes pringlei Rose | Central & SW. Mexico. |
|  |  | Ribes grande Rose | Mexico (Puebla) |
|  |  | Ribes sanguineum Pursh – flowering currant, redflower currant, blood currant, sticky blood currant, blackseed blood currant, winter currant | western United States and Canada. |
|  |  | Ribes tortuosum Benth. | Mexico |
|  |  | Ribes viscosissimum Pursh – sticky currant | United States, Canada |
|  |  | Ribes wolfii Rothr. – Wolf's currant | northern Idaho, northeastern Oregon, and southeastern Washington.  Utah, Colorado, Arizona, and New Mexico, Mexico |
Subgenus Ribes L. > Section Coreosma (Spach) Jancz.

Bagian ini terdiri dari kismis hitam (black currants) Eurasia dan Amerika.
| Flowers | Fruit | Scientific name | Distribution |
| --- | --- | --- | --- |
|  |  | Ribes americanum Mill. – American blackcurrant, wild blackcurrant | Canada (from Alberta to Nova Scotia) and the northern United States (from New England to Washington, with additional populations in Colorado and New Mexico) |
|  |  | Ribes bracteosum Douglas ex Hook. – stink currant | southeastern Alaska to Mendocino County in California |
|  |  | Ribes dikuscha Fisch. ex Turcz. | Siberia to Russian Far East. |
|  |  | Ribes hudsonianum Richards – northern blackcurrant, Hudson Bay currant, western blackcurrant | Canada, from Quebec westwards; and parts of the United States (Alaska, the Great Lakes region, the northern Rockies, Cascades, Blue Mountains, and other parts of the Northwest) |
|  |  | Ribes janczewskii Pojark. | Kazakhstan, Kyrgyzstan, Tajikistan |
|  |  | Ribes japonicum Maxim. – Japanese blackcurrant, thornless blackcurrant | Japan (Hokkaido, Honshu, Shikoku) |
|  |  | Ribes malvifolium Pojark. | Tadzhikistan |
|  |  | Ribes nigrum L. – Blackcurrant, European blackcurrant | northern Europe and northern Asia |
|  |  | Ribes procumbens Pall. – trailing redcurrant | Siberia to N. Korea, Japan (C. Honshu) |
|  |  | Ribes ussuriense Jancz. – Korean blackcurrant | Siberia to N. Korea, Japan (C. Honshu) |
|  |  | Ribes viburnifolium A.Gray – Island gooseberry | Southern California |
Subgenus Ribes L. > Section Symphocalyx Berland.

| Flowers | Fruit | Scientific name | Distribution |
| --- | --- | --- | --- |
|  |  | Ribes aureum Pursh – buffalo currant, clove currant, golden currant. Includes well-known cultivar 'Gwen.' | Canada, most of the United States (except the southeast) and northern Mexico. |
Subgenus Ribes L. > Section Grossularioides ( Jancz.) Rehd.

Bagian ini terdiri dari kismis berduri atau bertangkai Gooseberry dari Amerika Utara.
| Flowers | Fruit | Scientific name | Distribution |
| --- | --- | --- | --- |
|  |  | Ribes lacustre (Pers.) Poir. – black gooseberry, prickly currant, black swamp gooseberry | California to Alaska and across North America east to Pennsylvania and Newfoundland, and south as far as New Mexico. |
|  |  | Ribes montigenum McClat. – gooseberry currant | Washington south to California and east as far as the Rocky Mountains |
Subgenus Ribes L. > Section Heritiera Jancz.

| Flowers | Fruit | Scientific name | Distribution |
| --- | --- | --- | --- |
|  |  | Ribes erythrocarpum Coville & Leiberg – Crater Lake currant | Cascade Mountains in the US State of Oregon |
|  |  | Ribes acerifolium T.J Howell – maple currant, mapleleaf currant | Canadian Province of British Columbia as well as to the northwestern United States (Washington, Idaho, Oregon) |
|  |  | Ribes glandulosum Grauer ex Weber – skunk currant, fetid currant | United States (Alaska, the Great Lakes region, the Appalachian Mountains, and the Northeast) |
|  |  | Ribes laxiflorum Pursh – trailing blackcurrant | from Alaska and Yukon south as far as northern California and New Mexico |
Subgenus Ribes L. > Section Parilla Jancz.

| Flowers | Fruit | Scientific name | Distribution |
| --- | --- | --- | --- |
|  |  | Ribes andicola Jancz. | Colombia |
|  |  | Ribes albifolium Ruiz & Pav. | Peru |
|  |  | Ribes austroecuadorense Freire-Fierro | Ecuador |
|  |  | Ribes chachapoyense Weigend & Breitkopf | Peru |
|  |  | Ribes colandina Weigend | Peru |
|  |  | Ribes contumazensis Weigend | Peru |
|  |  | Ribes costaricense Weigend | Costa Rica |
|  |  | Ribes cucullatum Hook. & Arn. | Argentina and Chile |
|  |  | Ribes dombeyanum  (Spach) Jancz. | Peru |
|  |  | Ribes ecuadorense Jancz. | Colombia, Ecuador |
|  |  | Ribes erectum Freire-Fierro | Colombia, Ecuador |
| | |  | Ribes fasciculatum Siebold & Zucc. – Japanese currant | China, Japan, and Korea, |
|  |  | Ribes hirticaule J.F.Macbr. | Peru |
|  |  | Ribes hirtum Willd. ex Roem. & Schult. | Colombia to Ecuador. |
|  |  | Ribes incarnatum Wedd. | Peru to W. Bolivia. |
|  |  | Ribes incertum J.F.Macbr. | Peru. |
|  |  | Ribes integrifolium Phil. | Chile |
|  |  | Ribes lehmannii Jancz. | Ecuador. |
|  |  | Ribes luteynii Weigend | Ecuador |
|  |  | Ribes macrobotrys Ruiz & Pav. | Peru |
|  |  | Ribes macrostachyum Jancz. | Peru. |
|  |  | Ribes magellanicum Jancz. | Chile and Argentina |
|  |  | Ribes nanophyllum Freire-Fierro & L.Endara | Ecuador |
|  |  | Ribes nitidissima Neger. | Chile |
|  |  | Ribes ovalifolium Jancz. | Peru |
|  |  | Ribes parvifolium Phil. | Chile. |
|  |  | Ribes pentlandii Britton | Peru to W. Bolivia |
|  |  | Ribes peruvianum Jancz. | Peru. |
|  |  | Ribes polyanthes Phil. | Chile. |
|  |  | Ribes praecox J.F.Macbr. | Peru |
|  |  | Ribes punctatum Ruiz & Pav. | Chile |
|  |  | Ribes ruizii Rehder. | Chile |
|  |  | Ribes sanchezii Weigend | Peru. |
|  |  | Ribes sardoum Martelli – Sardinian currant | Sardegna |
|  |  | Ribes steinbachiorum Weigend & Binder | Bolivia |
|  |  | Ribes sucheziense Jancz. | Bolivia |
|  |  | Ribes tolimense Cuatrec. | Colombia |
|  |  | Ribes trilobum Meyen. | Central & S. Central Chile. |
|  |  | Ribes valdivianum Phil. | Chile |
|  |  | Ribes weberbaueri Jancz. | Peru |
Subgenus Ribes L. > Section Ribes L.

| Flowers | Fruit | Scientific name | Distribution |
| --- | --- | --- | --- |
|  |  | Ribes altissimum Turcz. ex Pojark. – tall currant | Mongolia, Russia (Siberia), China (Xinjiang) |
|  |  | Ribes biebersteinii Berland. ex DC. | E. Turkey to NW. Iran. |
|  |  | Ribes griffithii Hook.f. & Thomson | Nepal to China (W. Sichuan, NW. Yunnan) |
|  |  | Ribes himalense Royle ex Decne.– smooth rock currant | Pakistan to SW China |
|  |  | Ribes latifolium Jancz. – broadleaf currant | China (S. Jilin) to N. Korea, Sakhalin to N. Japan |
|  |  | Ribes longeracemosum Franch. – Tibet thornless blackcurrant | China (Sichuan, Yunnan, W. Hubei). |
|  |  | Ribes mandshuricum (Maxim.) Kom. | Russian Far East to N. & E. Central China and Korea. |
|  |  | Ribes meyeri Maxim. – Meyer's currant | Central Asia to Mongolia and NE. Afghanistan |
|  |  | Ribes moupinense Franch. | Central & S. China. |
|  |  | Ribes multiflorum Kit. – manyflower currant | Central Italy, Balkan Peninsula to W. Central Turkey |
|  |  | Ribes pallidiflorum Pojark. | northeastern China to Russia |
|  |  | Ribes petraeum Wulf. – rock currant, rock redcurrant, Bieberstein's rock currant | Europe |
|  |  | Ribes rubrum L. – redcurrant, white currant | Europe |
|  |  | Ribes sachalinense (F.Schmidt) Nakai | Sakhalin to Japan (Hokkaido, Honshu, Shikoku). |
|  |  | Ribes setchuense Jancz. | China (Sichuan, SE. Gansu) |
|  |  | Ribes spicatum Robson – Nordic redcurrant, Nordic currant, downy currant | northern Europe and northern Asia |
|  |  | Ribes soulieanum Jancz. | Tibet to China (NW. Yunnan). |
|  |  | Ribes triste Pall. – northern redcurrant or swamp redcurrant, wild redcurrant | Canada and the northern United States, as well as in eastern Asia (Russia, China, Korea, Japan) |
|  |  | Ribes turbinatum Pojark. | Kazakhstan |
Subgenus Grossularia (Mill.) Pers. > Section Grossularia(Mill.) Nutt.

| Flowers | Fruit | Scientific name | Distribution |
| --- | --- | --- | --- |
|  |  | Ribes aciculare Sm. – needle-spined gooseberry | northern China, Siberia. |
|  |  | Ribes alpestre Wall. ex Decne. | from Afghanistan to SW China |
|  |  | Ribes ambiguum Maxim. | China South-Central, Japan |
|  |  | Ribes burejense F.Schmidt | China, N Korea, Mongolia, Russia |
|  |  | Ribes curvatum Small – Granite gooseberry | United States (Texas, Oklahoma, Louisiana, Arkansas, Tennessee, Georgia, Alabama) |
|  |  | Ribes cynosbati L. – prickly gooseberry, eastern prickly gooseberry, dogberry, dog bramble | eastern and central United States and Canada |
|  |  | Ribes divaricatum Douglas – spreading gooseberry, wild gooseberry, coast gooseberry, coastal black gooseberry, Parish's gooseberry, Worcesterberry | western North America from British Columbia to California |
|  |  | Ribes echinellum (Cov.) Rehder – Miccosukee gooseberry | Florida, South Carolina |
|  |  | Ribes formosanum Hayata | Taiwan. |
|  |  | Ribes grossularioides Maxim. – Japanese gooseberry, catberry | Japan |
|  |  | Ribes hirtellum Michx. – North American gooseberry, hairystem gooseberry, currant gooseberry | Canada and the northern United States |
|  |  | Ribes horridum Rupr. – thorny currant | Russian Far East to N. Korea, Japan |
|  |  | Ribes inerme Rydb. – whitestem gooseberry, Klamath gooseberry | British Columbia to California and westward to the Rocky Mountains |
|  |  | Ribes missouriense Nutt. – Missouri gooseberry | north-central United States (Great Lakes, upper Mississippi and lower Missouri Valleys) |
|  |  | Ribes niveum Lindl. – snow gooseberry, slender-branched gooseberry | western United States (Washington, Idaho, Oregon, and Nevada with isolated populations in Colorado and New Mexico) |
|  |  | Ribes oxyacanthoides L. – American mountain gooseberry, Canadian gooseberry, stream gooseberry, Henderson's gooseberry, Idaho gooseberry | Alaska through much of Canada and the western and north-central United States |
|  |  | Ribes rotundifolium Michx. – Appalachian gooseberry, round-leaved gooseberry | Massachusetts and the Appalachian Mountains south as far as South Carolina and Tennessee |
|  |  | Ribes sinanense F.Maek. – Chinese gooseberry | Japan (C. Honshu) |
|  |  | Ribes stenocarpum Maxim. – narrow-fruited currant | S. & E. Qinghai to China Gansu, Shaanxi, NW. Sichuan |
|  |  | Ribes uva-crispa L. – gooseberry, wild gooseberry, European gooseberry, English gooseberry | Europe, the Caucasus and northern Africa |
Subgenus Hesperia A.Berger

| Flowers | Fruit | Scientific name | Distribution |
| --- | --- | --- | --- |
|  |  | Ribes amarum McClatchie – bitter gooseberry | California |
|  |  | Ribes californicum Hook. & Arn. – Hillside gooseberry, California gooseberry, Monterey gooseberry | California |
|  |  | Ribes cruentum Greene – shinyleaf currant, Oregon currant | California, Oregon |
|  |  | Ribes leptosma (Coville) Fedde | California |
|  |  | Ribes menziesii Pursh – Canyon gooseberry, Menzies' gooseberry | California and Oregon |
|  |  | Ribes roezlii Reg. – Sierra gooseberry, Roezl's gooseberry | California, its distribution extending east into Nevada and north into Oregon |
|  |  | Ribes victoris Greene – Victor's gooseberry | California |
Subgenus Lobbia A. Berger

| Flowers | Fruit | Scientific name | Distribution |
| --- | --- | --- | --- |
|  |  | Ribes binominatum A.Heller – ground gooseberry | northern California and western Oregon. |
|  |  | Ribes lasianthum Greene – alpine gooseberry | California, Nevada |
|  |  | Ribes leptanthum A.Gray – trumpet gooseberry | Arizona, Colorado, New Mexico, Texas, and Utah |
|  |  | Ribes lobbii A.Gray – gummy gooseberry | United States (Siskiyou Mountains, eastern Columbia Gorge, Crater Lake National Park, Mount Rainier National Park, Olympic National Park) and British Columbia in Canada |
|  |  | Ribes marshallii Greene – Hupa gooseberry | southern Oregon and northern California |
|  |  | Ribes microphyllum Kunth | Guatemala, Mexico |
|  |  | Ribes pinetorum Greene – orange currant | Arizona and New Mexico. |
|  |  | Ribes quercetorum Greene – rock gooseberry | California |
|  |  | Ribes sericeum Eastw. – Lucia gooseberry | California |
|  |  | Ribes tularense (Coville) Fedde. – Tulare gooseberry | southern California |
|  |  | Ribes velutinum Greene – desert gooseberry, Gooding's gooseberry | Montana, Idaho, Washington, Oregon, Utah, Nevada, California, and Arizona |
|  |  | Ribes watsonianum Koehne – spring gooseberry | Washington and Oregon. |
Subgenus Lobbia A. Berger > Section Robsonia Berland.

| Flowers | Fruit | Scientific name | Distribution |
| --- | --- | --- | --- |
|  |  | Ribes speciosum Pursh – fuchsia-flowered gooseberry | southern California and Baja California |
|  |  | Ribes thacherianum (Jeps.) Munz | coast of California |
Hybrids

| Flowers | Fruit | Scientific name | Parents |
| --- | --- | --- | --- |
|  |  | Ribes x bethmontii Jancz. | Ribes malvaceum x R. sanguineum |
|  |  | Ribes × culverwellii | Ribes nigrum x  Ribes uva-crispa |
|  |  | Ribes × futurum Jancz. | Ribes rubrum × Ribes warszewiczii |
|  |  | Ribes x gonduini Jancz. | Ribes petraeum × Ribes rubrum |
|  |  | Ribes × gordonianum Lem. | Ribes odoratum × Ribes sanguineum |
|  |  | Ribes × holocericeum Otto & A.Dietr. | Ribes petraeum × Ribes spicatum |
|  |  | Ribes × houghtonianum Jancz. | Ribes rubrum × Ribes spicatum |
|  |  | Ribes × koehneanum Jancz. | Ribes multiflorum × Ribes rubrum |
|  |  | Ribes × nidigrolaria Rud.Bauer & A.Bauer – Jostaberry | R. divaricatum x  R. uva-crispa |
|  |  | Ribes x varoi Blanca | Ribes uva-crispa × Ribes petraeum |

Ribes achurjani Mulk.
Ribes hartwegianum Jancz.
Ribes melananthum Boiss. & Hohen.
Ribes van-fleetianum (A.Berger) Standl.
Kecepatan relatif

Kecepatan relatif, dilambangkan  {\vec {v}}_{B}\mid _{A} (juga  {\vec {v}}_{BA}atau  {\vec {v}}_{BrelA}), adalah kecepatan sebuah benda A relatif terhadap kecepatan benda B.
Mekanika klasik > Dalam bidang satu dimensi (non-relativitas)

Kita mulai dengan gerakan relatif dalam fisika klasik, (atau non relativitas, atau fisika Newtonian) bahwa semua kecepatan jauh lebih lambat daripada kecepatan cahaya. Batas ini dikaitkan dengan transformasi Galileo. Gambar tersebut menunjukkan seorang pria di atas kereta, di tepi belakang. Pada pukul 1 siang dia mulai berjalan maju dengan kecepatan berjalan 10 km/jam (kilometer per jam). Kereta ini melaju dengan kecepatan 40 km/jam. Gambar tersebut menggambarkan pria dan kereta api pada dua waktu yang berbeda: pertama, saat perjalanan dimulai, dan juga satu jam kemudian pada pukul 14.00. Angka tersebut menunjukkan bahwa pria tersebut berada 50 km dari titik awal setelah melakukan perjalanan (dengan berjalan kaki dan dengan kereta api) selama satu jam. Ini, menurut definisi, adalah 50 km/jam, yang menunjukkan bahwa rumus untuk menghitung kecepatan relatif dengan cara ini adalah dengan menjumlahkan kedua kecepatan.
Gambar tersebut menampilkan jam dan penggaris untuk mengingatkan pembaca bahwa meskipun logika untuk kalkulasi ini tampak benar, namun membuat asumsi yang salah tentang bagaimana jam dan penggaris berperilaku. (Lihat Eksperimen pemikiran kereta api dan platform.) Untuk mengenali bahwa model klasik gerakan relatif ini melanggar relativitas khusus, kami menggeneralisasi contoh ke dalam persamaan:
\underbrace {{\vec {v}}_{M\mid E}} _{\text{50 km/jam}}=\underbrace {{\vec {v}}_{M\mid T}} _{\text{10 km/jam}}+\underbrace {{\vec {v}}_{T\mid E}} _{\text{40 km/jam}}
keteranggan:
{{\vec {v}}_{M\mid E}} adalah kecepatan M relatif terhadap E
{{\vec {v}}_{M\mid T}} adalah kecepatan M relatif terhadap T
{{\vec {v}}_{T\mid E}} adalah kecepatan T realatif terhadap E
Ekspresi yang sepenuhnya sah untuk "kecepatan A relatif terhadap B" mencakup "kecepatan A terhadap B" dan "kecepatan A dalam sistem koordinat di mana B selalu diam". Pelanggaran relativitas khusus terjadi karena persamaan kecepatan relatif ini salah memprediksi bahwa pengamat yang berbeda akan mengukur kecepatan yang berbeda ketika mengamati gerakan cahaya.