izzako/sundanese-pixelgpt huggingface dataset:
Gaya jeung kapindahan duanana mangrupa kuantitas véktor sarta dihijikeun maké kakalian titik (dot product) pikeun ngitung usaha mékanik, nu mangrupa kuantitas skalar: formula_3 (1) di mana formula_4 nyaéta sudut antara véktor gaya jeung véktor kapindahan
Supaya rumus ieu lumaku, [[gaya jeung sudut kudu tetep konstan
Jalur liliwatan obyék kudu salawasna tetep dina garis tunggal, sanajan mungkin ngarobah arah sabot gerak sapanjang garis kasebut
Dina kaayaan di mana gaya robah sapnjang [[waktu]], atawa jalur kasebut nyimpang tina garis lempeng, persamaan (1) umumna henteu lumaku sanajan dimungkinkeun pikeun ngabagi gerak kasebut kana tahapan-tahapan nu leutik, antukna gaya jeung gerak bisa dikira-kira konstan dina tiap tahapan, sarta tuluy nganyatakeun usaha sakabéhna salaku jumlah ti tahapan-tahapan ieu
Définisi umum pikeun usaha mékanik dinyatakeun ku [[integral garis]] kieu: formula_5 (2) di mana: "C" nyaéta [[kurva]] nu diliwatan ku obyék; \vec F nyaéta [[gaya]]; \vec s nyaéta véktor posisi
Pernyataan "δW"=F·ds mangrupa [[diférensial teu pasti]] nu boga harti yén itungan "WC" gumantung kana jalur liliwatan sarta teu bisa didiférensiasi pikeun ngahasilkeun F·ds
Persamaan (2) ngajelaskeun kumaha gaya teu-enol bisa migawé usaha enol
Kasus paling basajan nyaéta gaya nu salawasna tegaklempeng kana arah gerak, nu ngajadikeun [[integran]] salawasna enol
Ieu nyaéta nu lumangsung salila gerak muter
Sanajan kitu, malah lamun integran sakapeung boga harga teu-enol, persamaan ieu masih bisa ngahasilkeun integrasi enol lamun integran sakapeung positif sakapeung négatif
Énergi mékanik hiji barang nyaéta bagian tina [[énergi]] totalna anu uduh ku parobahan ku usaha mékanik
Énergi ieu ngawengku [[énergi kinétik]] jeung [[énergi poténsial]]
Sawatara bentuk énérgi nu kawénéhan nu teu kaasup énergi mékanik nyaéta [[énergi térmal]] (nu bisa dironjatkeun ku usaha [[gésék]]an, tapi teu gampang diturunkeun) sarta [[énergi cicing]] (anu tetep sapanjang [[massa cicing]] tetep sarua)
Lamun hiji gaya luar "F" nimpah kana hiji obyék, nu ngabalukarkeun [[énergi kinétik]]na robah ti "Ek1" ka "Ek2", mangka: formula_6 Jadi urang bisa meunangkeun hasilna, nyaéta usaha mékanik anu dilakukeun ku gaya luar nu nimpah hiji barang proporsional (sabanding) jeung béda dina kuadrat [[laju]]
(Perhatikeun yén seler nu pangahirna dina persamaan di luhur nyaéta formula_7 lain formula_8.)
Prinsip "kalanggengan (konsevasi) énergi mékanik" nganyatakeun yén, lamun hiji sistem tunduk ngan kana [[gaya konservatif]] (upamana ngan kana [[gaya gravitasi]]), atawa lamun jumlah usaha sakabéh gaya séjénna enol, énergi mékanikna tetep konstan
Contona, lamun hiji obyék kalayan massa konstan ragrag bébas, énergi total dina posisi 1 baris sarua jeung énergi total dina posisi 2. formula_9 di mana Usaha luar biasana baris dipigawé ku gaya gésék antara sistem nu gerak atawa gaya internal non konservatif dina sistem atawa kaleungitan énergi lantaran panas
Dina fisika jeung élmu alam lianna, énergi (tina basa Yunani - "energeia", "aktivitas, operasi", tina - "energos", "aktif, digawé") nyaéta hiji kuantitas fisik skalar anu mangrupa sifat obyék jeung sistem anu langgeng
Énergi mindeng didéfinisikeun salaku kamampuh pikeun ngalakukeun usaha
SI jeung hijian nu patali
Hijian SI pikeun énergi sarta usaha nyaéta joule (J), dingaranan kieu pikeun ngahormat James Prescott Joule jeung percobaanana dina persamaan mékanika panas
1 joule sarua jeung 1 newton-méter sarta, dina istilah hijian SI, 1 J sarua jeung 1 kg m2 s−2
"Usaha" didéfinisikan minangka "integral wates" gaya F sajauh s: formula_1 Persamaan di luhur nganyatakeun yén usaha (W) sarua jeung integral ti kakalian titik (dot product) antara gaya formula_2 dina hiji barang jeung infinitesimal posisi barang formula_3
Énergi kinétik nyaéta bagian ti énergi anu patali jeung gerakan hiji barang
formula_4 Persamaan di luhur nganyatakeun yén énergi kinétik (E_k) sarua jeung integral ti dot product "laju" formula_5 hiji barang jeung infinitesimal moméntum barang formula_6
Lalawanan jeung énergi kinétik, anu mangrupa énergi ti hiji sistem balukar gerakna, atawa gerak partikel internalna, énergi poténsial ti hiji sistem nyaéta énergi anu patali jeung konfigurasi ruang ti komponén-komponénna sarta interaksi maranéhanana
Jumlah partikel anu ngaluarkeun gaya sacara otomatis nyieun hiji sistem kalawan énergi poténsial
Gaya-gaya kasebut, contona, bisa timbul ti interaksi éléktrostatik (tempo hukum Coulomb), atawa gravitasi
"Énergi internal" nyaéta énergi kinétik nu patali jeung gerak molekul-molekul, sarta énergi poténsial anu patali jeung geteran puteran sarta énergi listrik ti atom-atom dina jero molekul
Pamakéan énergi ku manusa
Cahya mangrupa salah sahiji bentuk énergi gelombang éléktromagnétik anu bisa ditempo ku panon
Cahya ogé mangrupa dasar ukuran pikeun hijian panjang méter: 1 méter nyaéta jarak anu diliwatan cahya dina rohangan hapa dina waktu 1/299,792,458 detik
Laju cahya nyaéta 299,792,458 méter pér detik
Cahya diperlukeun dina kahirupan sapopoé
Panonpoé nyaéta sumber cahya utama di Bumi
Tutuwuhan héjo merlukeun cahya pikeun nyieun kadaharan
Sipat-sipat cahya nyaéta, cahya ngarambat lempeng ka sakabéh arah
Buktina nyaéta urang bisa nempo hiji lampu anu murub ti sagala juru dina hiji rohangan nu poék
Lamun cahya kahalang, bayangan anu dihasilkeun dibalukarkeun ku cahya anu ngarambat henteu bisa méngkol
Tapi cahya bisa dipantulkeun
Cahya baris dipéngkolkeun lamun datangna miring ngaliwatan médium anu béda kawas ti udara (hawa) kana kaca tuluy ngaliwatan cai
Kaayaan ieu disebut pangbéngkokan cahya atawa réfraksi cahya
Hal ieu kajadian alatan cahya gerak leuwih gancang dina medium anu kurang padet (mundel)
Tapi cahya anu datang kalawan sudut 90 darajat (ajeg lempeng) ngaliwatan médium anu béda henteu diréfraksi
Conto réfraksi dina hal sapopoé nyaéta kawas dina kasus sedotan inuman anu katempo béngkok sarta leuwih badag dina jero cai, atawa dina kasus dasar balong nu katempo leuwih déét batan jero sabenerna
Pantulan cahya gumantung kana rupa beungeut pamantul
Bayangan bisa ditempo dina jero eunteung alatan aya pantulan cahya
Pantulan cahya éta leuwih alus sarta "teratur" dina beungeut pamantul anu rata
Pantulan cahya rada surem dina "beungeut" pamantul anu henteu rata
Eunteung sarta "beungeut" cai anu hérang sarta tenang mangrupa pamantul cahya anu alus
Hal ieu ngajadikeun urang bisa nempo beungeut sarta awak urang dina jero eunteung
Warna-warna dina cahya panonpoé
Cahya bodas panonpoé diwangun ku tujuh warna dasar nyaéta: Lamun tujuh warna ieu pagalo, cahya bodas baris dihasilkeun
Warna-warna dina cahya bodas panonpoé bisa dipisah-pisah ku ngagunakeun prisma ngajadi sakumpulan warna nu sinambung
Sakumpulan warna nu sinambung ieu dipikawanoh minangka spéktrum cahya sedengkeun pamisahan cahya bodas kana spéktrum ieu dipikawanoh minangka difraksi cahya
Katumbiri nyaéta conto spéktrum anu kabentuk sacara alamiah
Katumbiri kabentuk saréngsé hujan, sabot cahya panonpoé diréfraksi ku tetesan cai hujan
Tetesan cai hujan éta lumaku minangka prisma anu misah-misah cahya panonpoé jadi tujuh warna
Pamisahan cahya bodas panonpoé
Spéktrum warna kabentuk alatan cahya anu béda warna karéfraksi dina sudut anu béda
Cahya wungu karéfraksi kalawan sudut panggedéna
Cahya beureum karéfraksi kalawan sudut pangleutikna
Warna-warna spéktrum kasebut digabungkan deui pikeun ngahasilkeun cahya bodas kalawan ngagunakeun dua prisma
Téori ngeunaan cahya
Téori abad ke-10
élmuwan Abu Ali Hasan Ibn Al-haitham (965 - kira 1040), nu dipikawanoh ogé salaku Alhazen, ngamekarkeun téori anu ngécéskeun penglihatan, ngagunakeun géometri sarta anatomi
Téori éta nganyatakeun yén saban titik dina wewengkon anu kasinaran cahya, ngaluarkeun sinar cahya ka sagala arah, tapi ngan hiji sinar ti saban titik éta anu asup ka panon sacara ajeg lempeng anu bisa ditempo
Cahya séjén anu keuna panon henteu sacara ajeg lempeng henteu bisa katempo
Manéhna ngagunakeun kaméra liang jarum contona, anu mintonkeun hiji bayangan tibalik
Alhazen nganggap yén sinar cahya nyaéta kumpulan partikel leutik anu usik dina laju nu tangtu
Manéhna ogé ngamekarkeun tééori Ptolemy ngeunaan réfraksi cahya tapi usaha Alhazen henteu dipikawanoh di Éropa nepi ka dina ahir abad ka-16
Isaac Newton nganyatakeun dina "Hypothesis of Light" dina taun 1675 yén cahya diwangun ku partikel lembut ("corpuscles") anu mancar ka sakabéh arah ti asalna
Téori ieu bisa dipaké pikeun ngajelaskeun pantulan cahya, tapi ngan bisa ngajelaskeun pembiasan kalawan nganggap rambatan cahya jadi leuwih gancang sabot ngasupan médium anu padet tumpat alatan daya tarik gravitasi leuwih kuat
Christiaan Huygens nganyatakeun dina abad ke-17 yén cahya nu mancar ka sakabéh arah minangka ciri-ciri gelombang
Tetempoan ieu ngagantikeun téori partikel lembut
Hal ieu dilantarankeun ku alatan gelombang henteu diganggu ku gravitasi, sarta gelombang jadi leuwih laun sabot ngasupan médium anu leuwih padet
Téori gelombang ieu nganyatakeun yén gelombang cahya baris silih ganggu (interférensi) jeung gelombang cahya anu séjén kawas gelombang sora (kawas anu disebut ku Thomas Young dina abad ka-18), sarta cahya bisa dipolarisasikeun
Kakurang téori ieu téh gelombang cahya jiga gelombang sora, merlukeun médium pikeun ngarambat
Hiji hipotésis anu disebut luminiferous aether geus diusulkan, tapi hipotésis éta henteu disatujuan
Dina taun 1845 Faraday manggihan yén sudut polarisasi ti hiji sinar cahya sabot sinar kasebut asup ngaliwatan material pamolarisasi bisa dirobah ku médan magnét
Ieu téh bukti kahiji lamun cahya pakuat-pakait jeung éléktromagnétisme
Faraday ngusulkeun dina taun 1847 yén cahya nyaéta gelombang éléktromagnétik nu boga frékuénsi luhur anu bisa ngarambat sanajan euweuh médium
Téori ieu diusulkan ku James Clerk Maxwell dina ahir abad ka-19, sarta nyebutkeun yén gelombang cahya nyaéta gelombang éléktromagnétik ku kituna henteu merlukeun médium pikeun ngarambat
Tapi téori rélativitas husus ngagantikeun anggapan ieu
Téori éléktromagnétik némbongkeun yén sinar kasat mata mangrupa bagian tina spéktrum éléktromagnétik
Téknologi pancaran radio diciptakeun dumasar kana téori ieu sarta masih dipaké
Laju cahya anu konstan dumasar kana persamaan Maxwell lalawanan jeung hukum-hukum mékanika gerak anu geus aya saprak jaman Galiléo, anu nganyatakeun yén sagala rupa laju nyaéta relatif ka nu nempo
Jawaban pikeun kontradiksi ieu satuluyna kapanggih ku Albert Einstein
Téori ieu dimimitian dina abad ka-19 ku Max Planck, anu nganyatakeun dina taun 1900 yén sinar cahya diwangun ku paket (kuantum) tanaga anu dipikawanoh salaku foton
Hadiah Nobel dina widang fisika dibikeun ka Planck minangka pangajén dina taun 1918 pikeun gawéna nimukeun téori kuantum, sanajan manéhna téh lain jelema anu kahiji ngawanohkeun prinsip dasar partikel cahya
Téori Dualitas partikel-gelombang
Téori ieu ngagabungkeun tilu téori anu saméméhna, sarta nganyatakeun yén cahya nyaéta partikel ogé gelombang
Ieu téh téori modéren anu ngécéskeun sipat-sipat cahya, ogé sipat-sipat partikel sacara umum
Téori ieu mimiti dijelaskeun ku Albert Einstein dina awal abad ka-20, dumasar kana karya tulisna ngeunaan éfék fotolistrik, sarta hasil panalungtikan Planck
Einstein némbongkeun yén énergi hiji foton sabanding jeung frékuénsina
Leuwih umum deui, téori kasebut ngécéskeun yén sakabéh barang miboga sipat partikel sarta gelombang, sarta sagala rupa percoaban (ékspérimen) bisa dilakonan pikeun ngabuktikeunana
Sipat partikel bisa leuwih gampang katempo lamun hiji obyék miboga massa anu badag
Dina taun 1924 ékspérimen nu dilakukeun ku Louis de Broglie némbongkeun éléktron ogé miboga sipat dualitas partikel-gelombang
Einstein meunangkeun pangajén Nobel dina taun 1921 dumasar karyana ngeunaan dualitas partikel-gelombang dina foton, sarta de Broglie nuturkeun tapak-lacakna menunagkeun pangajén Nobel dina taun 1929 pikeun panalungtikan partikel-partikel anu séjén
Panjang gelombang cahya katémbong
Cahya katémbong mangrupa bagian tina spéktrum gelombang éléktromagnétik anu miboga panjang gelombang antara leuwih kurang 400 nanométer ("nm") nepi ka 800 nm (dina udara)
formula_1, Rumus laju-cahya
di mana "λ" nyaéta panjang gelombang, "f" nyaéta frékuénsi, "v" nyaéta laju cahya
Lamun cahya ngarambat dina jero rohangan hapa, jadi "v" = "c", antukna formula_2, di mana "c" nyaéta laju cahya
Urang kaci ngajelaskeun "v" minangka formula_3 di mana "n" nyaéta konstanta (indéks bias) anu mana nyaéta sipat materi anu diliwatan ku cahya
Parobahan dina laju cahya
Kabéh cahya usik dina laju anu katepi (kahingga)
Sanajan hiji jalma ngimeutan yén laju cahya nyaéta "c", laju cahya dina rohangan hapa, nyaéta "c" = 299,792,458 méter pér detik (186,282.397 mil pér detik); tapi, lamun cahya ngaliwatan obyék anu bisa ditembus cahya kawas hawa, cai jeung kaca, lajuna ngurangan, sarta cahya kasebut ngarandapan pembiasan
Nyaéta "n"=1 dina rohangan hapa sarta "n"&gt;1 dina jero médium séjén
Sajarah ukar-ukur laju cahya
Laju cahya geus mindeng diukur ku ahli fisika
Ukar-ukur munggaran anu pangalusna geus dipigawé ku Olaus Roemer (ahli fisika Denmark), dina taun 1676
Manéhna nyiptakeun tata cara ngukur laju cahya
Manéhna ngimeutan sarta nyatet gerak planét Saturnus sarta salah sahiji bulanna kalawan ngagunakeun teleskop
Roomer nimukeun yén bulan kasebut ngorbit Saturnus sakali saban 42 1/2 jam
Masalahna nyaéta lamun Bumi jeung Saturnus pajauh, puteran orbit bulan kasebut katempo nambahan
Ieu ngabuktikeun yén cahya merlukeun waktu leuwih lila pikeun nepi ka Bumi
Ku cara ieu laju cahya bisa diitung kalawan nganalisa jarak antar planét dina mangsa-mangsa nu tangtu
Roemer meunangkeun angka laju cahya sagedé 227,000 kilométer pér detik
Mikel Giovanno Tupan ngagunakeun eunteung nu muter pikeun ngukur waktu anu diperlukeun cahya pikeun bulak-balik ti Gunung Wilson ka Gunung San Antonio di California
Ukar-ukur nu jitu ngahasilkeun laju 299,796 kilométer/detik
Dina pamakéan sapopoé, angka ieu dibuleudkeun jadi 300,000 kilométer/detik
Kelir jeung panjang gelombang
Panjang gelombang anu béda-béda ditarjamahkeun ku otak manusa salaku warna, kalawan beureum nyaéta panjang gelombang pangpanjangna (frékuénsi pangpondokna) nepi ka wungu kalawan panjang gelombang pangpondokna (frékuénsi pangluhurna)
Cahya kalawan frékuénsi di sahandapeun 400 nm sarta saluhureun 700 nm henteu bisa katempo ku manusa
Cahya disebut sinarultraviolét dina wates frékuénsi luhur sarta infrabeureum (IR atawa infrared) dina wates frékuénsi pondok
Sanajan manusa henteu bisa nempo sinar infrabeureum, kulit manusa bisa ngarasakeunana dina wangun panas
Aya ogé kaméra anu bisa nyerek sinar Infrabeureum sarta ngarobahna jadi sinar katémbong
Kaméra kawas ieu disebut "night vision camera"
Radiasi ultaviolét henteu dirasakan samasakali ku manusa kajaba lamun kakeunaan dina jangka waktu anu lila, hal ieu bisa ngabalukarkeun kulit kabeuleum sarta kanker kulit
Sawatara sato kawas nyiruan bisa nempo sinar ultraviolét, sedengkeun sato-sato séjénna kawas oray Viper bisa ngarasakeun IR ku alat husus
Di handap ieu aya daptar kuantitas anu dipaké pikeun ngukur cahya Tempo ogé
Kopo, Soréang, Bandung
Kutawaringin nyaéta salah sahiji désa di Kacamatan Kutawaringin, Kabupatén Bandung, Propinsi Jawa Kulon, Indonésia
Gajah Mekar nyaéta salah sahiji désa di Kacamatan Kutawaringin, Kabupatén Bandung, Propinsi Jawa Kulon, Indonésia
Jatisari, Soréang, Bandung
Jelegong, Soréang, Bandung
Padasuka nyaéta salah sahiji désa di Kacamatan Kutawaringin, Kabupatén Bandung, Propinsi Jawa Kulon, Indonésia
Pameuntasan nyaéta salah sahiji désa di Kacamatan Kutawaringin, Kabupatén Bandung, Propinsi Jawa Kulon, Indonésia
Sukamulya nyaéta salah sahiji désa di Kacamatan Kutawaringin, Kabupatén Bandung, Propinsi Jawa Kulon, Indonésia
Ngokolakeun runtah atawa manajemén runtah (Basa Indonésia: "pengelolaan sampah", , ) nyaéta prosés ngokolakeun runtah kaasup ngumpulkeun, ngirimkeun, mrosés, ngadaur ulang atawa miceun éta runtah
Istilah ieu biasana patali jeung bahan nu dihasilkeun tina aktivitas manusa, tur ilaharna dikokolakeun téh pikeun ngurangan pangaruhna kana kasehatan, lingkungan atawa estetika
Sanajan geus jadi kasapukan yén runtah téh mangrupa bahan nu teu dipikahayang, lain hartina runtah euweuh gunana
Malah, lamun bisa ngokolakeunnana runtah ogé bisa mibanda mangpaat ekonomis
Manajemén runtah ogé ditérapkeun keur ngahadéan sumber daya alam
Manajemén runtah bisa patali jeung bahan padet, cair, gas atawa radioaktif, kalayan cara jeung widang kaahlian nu béda-béda keur unggal bahan-bahan eta
Gerak muter nyaéta gerak hiji barang anu nyieun jalur liliwatan mangrupa bunderan nu ngalingkung hiji titik nu tetep
sangkan hiji barang bisa gerak muter, ieu barang merlukeun ayana gaya anu bakal "mengkolkeun" barang kasebut nuju ka puseur bunderan
Gaya ieu dingaranan gaya séntripétal
Hiji gerak muter beraturan (merenah) bisa disebut ogé gerak digancangkeun merenah, lantaran perlu ayana hiji pacepetan (akselerasi) anu gedéna tetep kalayan tujuan anu robah, anu ngabalukarkeun robahna tujuan gerak hiji barang sangkan ngaliwatan jalur anu ngawangun bunderan Richard S. Westfall, "Circular Motion in Seventeenth-century Mechanics", Isis, Vol
(Jun., 1972), pp
184-189.. Diménsi pikeun gerak muter
Diménsi-diménsi anu ngagambarkeun hiji gerak muter nyaéta sudut, laju sudut sarta akselérasi sudut anu masing-masing dilambangkeun ku formula_1, formula_2 sarta formula_3
Diménsi-diménsi ieu lamun dianalogikan jeung gerak liniér sarimbag jeung posisi, laju sarta akselérasi anu masing-masing dilambangkeun ku formula_4, formula_5 sarta formula_6
Diférensiasi jeung integrasi
Diménsi-diménsi gerak muter mibanda hubungan dina prosés integrasi jeung diférensiasi
formula_7 formula_8 formula_9 Hubungan antara diménsi sudut jeung tangénsial
Antara diménsi gerak liniér jeung gerak muter aya hiji hubungan ngaliwatan formula_10 husus pikeun komponén tangénsial, nyaéta formula_11 Perhatikeun yén di dieu dipaké formula_12 anu didéfinisikan sabagé jarak anu diliwatan atawa sisi gondéwa anu geus diliwatan salila hiji selang waktu sarta lain ngan posisi dina hiji waktu, nyaéta formula_13 pikeun hiji selang waktu singket atawa sudut anu heureut
Rupa-rupa gerak muter
Gerak muter bisa dibédakeun jadi dua rupa dumasar kana kasarageman laju sudutna formula_2, nyaéta: Gerak muter merenah
Gerak muter merenah nyaéta gerak muter kalawan laju sudut formula_2 nu tetep
Harga laju sudut bisa dibeunangkeun ku cara ngabagi laju tangénsial formula_16 ku radius puteran formula_10 formula_18 Arah tujuan laju liniér formula_5 dina gerak muter merenah sok nyigeung jalur liliwatan, anu hartina arah tujuanana sarua jeung arah tujuan laju tangénsial formula_16
Tetepna harga laju formula_16 alatan tina tetepna harga formula_2
Sajaba ti éta, aya ogé akselérasi radial formula_23 anu hargana tetep sarta arah tujuanana anu robah
Akselérasi ieu disebut akselérasi séntripétal, di mana arah tujuanana sok ngarah puseur bunderan
formula_24 Lamun formula_25 nyaéta waktu anu diperlukeun pikeun ngabéréskeun hiji puteran sapinuhna dina jalur bunderan formula_26, mangka bisa ogé dituliskeun formula_27 Kinematika gerak muter beraturan nyaéta formula_28 di mana formula_29 mangrupa sudut anu diliwatan salila hiji waktu formula_30, formula_31 mangrupa sudut awal sarta \omega\
mangrupa laju sudut (anu tetep hargana)
Gerak muter robah merenah
Gerak muter robah merenah nyaéta gerak muter kalawan laju sudut formula_3 nu tetep
Dina gerak ieu aya akselérasi tangensial formula_33 (anu dina hal ieu sarua jeung akselérasi liniér) anu nyigeung jalur kuliling bunderan (pahapit jeung arah tujuan laju tangénsial formula_16)
formula_35 Kinematika GMBB nyaéta formula_36 formula_37 formula_38 di mana formula_3 nyaéta akselérasi sudut anu hargana tetep sarta formula_40 nyaéta laju sudut awal
Gerak muter bisa ogé dinyatakeun dina persamaan paramétrik kalawan leuwih tiheula ngadéfinisikeun: pikeun saterusna dijieun persamaanna "Chapter 22 Parametric Equation,", Department of Mathematics, University of Washington, Math 124 Materials (Autumn), ch 22, pp
308 .. Hal kahiji anu kudu dipigawé nyaéta ngitung radius liliwatan formula_10 : formula_45 Sanggeus meunang harga radius liliwatan, persamaan bisa dituliskeun: formula_46 formula_47 jeung dua konstanta formula_48 sarta formula_49 anu masih kudu ditangtukeun hargana
Kalawan pasaratan saméméhna, nyaéta dipikanyahona harga formula_41, mangka bisa ditangtukeun harga formula_48 sarta formula_49: formula_53 formula_54 Perlu dipikanyaho yén sabenerna formula_55 alatan mangrupa sudut mimiti gerak muter
Hubungan antar diménsi liniér jeung angular
Ku ngagunakeun persamaan paramétrik, geus diwatesan yén diménsi liniér anu dipaké saukur diménsi tangensial atawa ngan komponén véktor dina arah tujuan sudut, anu hartina euweuh komponén véktor dina arah tujuan radial
Ku watesan ieu, hubungan antara diménsi liniér (tangensial) sarta sudut bisa kalawan gampang ditimukeun
Laju tangensial sarta laju sudut
Laju liniér total bisa katimu ngaliwatan persamaan: formula_56 sarta alatan watesan impleméntasi persamaan paramétrik dina gerak muter, mangka formula_57 kalawan formula_58 formula_59 dihasilkeun formula_60 formula_61 ku kituna formula_62 formula_63 formula_64 Akselerasi tangensial jeung laju sudut
Ku cara anu sarua jeung nu saméméhna, akselérasi liniér total bisa katimu ngaliwatan persamaan: formula_65 sarta alatan watesan impleméntasi persamaan paramétrik dina gerak muter, mangka formula_66 kalawan formula_67 formula_68 dihasilkeun formula_69 formula_70 ku kituna formula_71 formula_72 formula_73 Laju sudut henteu tetep
Persamaan paramétrik bisa ogé dipaké lamun gerak muter GMBB, atawa lain deui GMB kalawan ayana laju sudut anu robah merenah (atawa ayana akselérasi)
Léngkah-léngkah anu sarua bisa dipigawé di dieu, tapi perlu diinget yén formula_74 kalawan formula_3 laju sudut sarta formula_40 laju sudut awal
Penurunan GMBB ieu baris jadi saeutik leuwih rumit dibandingkeun dina kasus GMB di luhur
Persamaan paramétrik di luhur, bisa dituliskeun dina wangun anu leuwih umum, nyaéta: formula_77 formula_78 di mana formula_79 nyaéta sudut anu diliwatan dina hiji waktu
Kawas geus disebutkeun di luhur ngeunaan hubungan antara formula_80, formula_81 jeung formula_82 ngaliwatan prosés integrasi sarta diférensiasi, mangka dina kasus GMBB hubungan-hubungan kasebut mutlak diperlukeun
Ku ngagunakeun aturan ranté dina ngalakonan diférensiasi posisi ti persamaan paramétrik katimu: formula_83 formula_84 kalawan formula_85 Bisa dibuktikeun yén formula_86 sarua jeung kasus dina GMB
Diférensiasi laju liniér dumasar waktu satuluyna ngahasilkeun formula_87 formula_88 anu bisa disederhanakan jadi formula_89 formula_90 Saterusna formula_91 anu umumna dituliskeun Ian Burley, Meg Carrington, Randy Kobes, Gabor Kunstatter, "Centripetal Acceleration", IUN/FYDE Introductory Physics Notes, circ:node6 , University of Winnipeg, 10/9/1997
formula_92 kalawan formula_93 anu mangrupa akselérasi sudut, sarta formula_94 anu mangrupa akselérasi séntripétal
Sélér séntripétal ieu mecenghul alatan obyék kudu "dipéngkolkeun" atawa lajuna kudu dirobah ku kituna gerak nuturkeun liliwatan bunderan
Gerak robah merenah
Gerak muter bisa ditoong minangka gerak robah merenah
Bédakeun jeung gerak lempeng robah merenah (GLBB)
Konsép laju anu robah sakapeung ngan dipahaman dina robahan badagna, dina gerak muter merenah (GMB) gedéna laju nyaéta tetep, tapi arah tujuanana anu robah sacara merenah, bandingkeun jeung GLBB anu arah tujuanana tetep tapi gedé lajuna anu robah merenah
Dina fisika, gaya téh nyaéta tarikan atawa dorongan anu bisa ngabalukarkeun hiji obyék nu boga massa diakselérasi (gerak tambah gancang atawa tambah laun)
Gaya boga badag jeung arah tujuan, anu ngajadikeun gaya salaku kuantitas véktor
Nurutkeun , hiji obyék kalayan massa nu tetep bakal diakselérasi (tambah gancang atawa tambah laun gerakna]] proporsional jeung gaya bérésih (néto) anu nimpah kana éta obyék sarta babanding tibalik jeung massana
Gaya anu nimpah kana obyék tilu diménsi bisa ogé ngabalukarkeun obyék kasebut muter atawa ngalaman deformasi, atawa ngahasilkeun parobahan tekenan
Kacondongan hiji gaya pikeun ngabalukarkeun puteran (akselerasi sudut) sabudeureun hiji sumbu disebut torsi
Deformasi jeung tekenan mangrupa hasil tina gaya-gaya strés dina jero hiji obyék
Since antiquity, scientists have used the concept of force in the study of stationary and moving objects
These studies culminated with the descriptions made by the third century BC philosopher Archimedes of how simple machines functioned
The rules Archimedes determined for how forces interact in simple machines are still a part of physics
éarlier descriptions of forces by Aristotle incorporated fundamental misunderstandings which would not be corrected until the seventeenth century by Isaac Newton
Newtonian descriptions of forces remained unchanged for néarly three hundred yéars
Current understanding of quantum mechanics and the standard model of particle physics associates forces with the fundamental interactions accompanying the emission or absorption of gauge bosons
Only four fundamental interactions are known: in order of decréasing strength, they are: strong, electromagnetic, weak, and gravitational
High-energy particle physics observations made during the 1970s and 1980s confirmed that the wéak and electromagnetic forces are expressions of a unified electroweak interaction
Einstein in his theory of general relativity explained that gravity is an attribute of the curvature of space-time
Since antiquity, the concept of force has been recognized as integral to the functioning of éach of the simple machines
The mechanical advantage given by a simple machine allowed for less force to be used in exchange for that force acting over a gréater distance
Analysis of the characteristics of forces ultimately culminated in the work of Archimedes who was especially famous for formulating a tréatment of buoyant forces inherent in fluids
Aristotle provided a philosophical discussion of the concept of a force as an integral part of Aristotelian cosmology
In Aristotle's view, the natural world held four elements that existed in "natural states"
Aristotle believed that it was the natural state of objects with mass on Earth, such as the elements water and éarth, to be motionless on the ground and that they tended towards that state if left alone
He distinguished between the innate tendency of objects to find their "natural place" (e.g., for héavy bodies to fall), which led to "natural motion", and unnatural or forced motion, which required continued application of a force
This théory, based on the everyday experience of how objects move, such as the constant application of a force needed to keep a cart moving, had conceptual trouble accounting for the behavior of projectiles, such as the flight of arrows
The place where forces were applied to projectiles was only at the start of the flight, and while the projectile sailed through the air, no discernible force acts on it
Aristotle was aware of this problem and proposed that the air displaced through the projectile's path provided the needed force to continue the projectile moving
This explanation demands that air is needed for projectiles and that, for example, in a vacuum, no projectile would move after the initial push
Additional problems with the explanation include the fact that air resists the motion of the projectiles
These shortcomings would not be fully explained and corrected until the seventeenth century work of Galileo Galilei, who was influenced by the late medieval idéa that objects in forced motion carried an innate force of impetus
Galiléo constructed an experiment in which stones and cannonballs were both rolled down an incline to disprove the Aristotelian theory of motion éarly in the seventeenth century
He showed that the bodies were accelerated by gravity to an extent which was independent of their mass and argued that objects retain their velocity unless acted on by a force, for example friction
Isaac Newton is the first person known to explicitly state the first, and the only, mathematical definition of force—as the time-derivative of momentum: formula_1
In 1687, Newton went on to publish his "Philosophiae Naturalis Principia Mathematica", which used concepts of inertia, force, and conservation to describe the motion of all objects
In this work, Newton set out three laws of motion that to this day are the way forces are described in physics
Massa nyaéta sipat fisika ti hiji barang, anu sacara umum bisa dipaké pikeun ngukur lobana materi anu aya dina hiji barang
Massa mangrupa konsép utama dina mékanika klasik sarta widang élmu séjén anu patali
Dina Sistem Internasional (SI), massa diukur dina hijian kilogram
Pakakas anu dipaké pikeun ngukur massa biasana nyaéta timbangan
Massa jeung beurat
Henteu kawas beurat, massa di satiap tempat sok sarua
Contona: massa urang sabot di bumi sarta di bulan sarua, tapi beurat urang di bumi jeung di bulan béda
Hubungan antara massa jeung beurat nyaéta massa*(akselerasi gravitasi) mangrupa beurat
F= m*g. F nyaéta "gaya", m nyaéta massa, sarta g nyaéta alselerasi gravitasi (daya tarik bumi)
Sawatara jalma nuliskeun rumus kasebut dina wangun W=m*g, di mana W nganyatakeun beurat
Nurutkeun élmu fisika, massa hiji jalma baris sarua di mana waé, tapi beurat jelema kasebut baris béda ti hiji tempat jeung tempat anu séjénna (beurat jelema kasebut di kutub baris leuwih gedé batan beuratna di katulistiwa)
Sarua jeung éta, beurat hiji barang di luhur beungeut laut baris leuwih gedé manan beuratna di puncak gunung anu luhur
Hal ieu kajadian alatan akselerasi gravitasi di kutub leuwih gedé batan di katulistiwa, sarta akselerasi gravitasi di luhur beungeut laut leuwih gedé di patempatan anu leuwih luhur (alatan jarakna ka puseur bumi leuwih jauh)
Waktu (basa Hormat: Waktos) nyaéta bagian tina "sistem" ukuran pikeun ngabandingkeun lila lumangsungna kajadian-kajadian sarta selang antara kajadian-kajadian di maksud
Dina hal ieu, "skala" waktu mangrupa "interval" antara dua kaayaan/kajadian, atawa bisa mangrupa lila lumangsungna hiji kajadian
"Skala' waktu diukur ku hijian detik, menit, jam, poé (Senén, Salasa, Rebo, Kemis, Jumaah, Saptu, Ahad), bulan (Januari, Pébruari, Maret, April, Méi, Juni, Juli, Agustus, Séptémber, Oktober, Nopémber, Désémber), taun, windu, dékadeu (dasawarsa), abad, milénium (alaf) sarta saterusna
Pikeun ngukur "skala" waktu anu lumangsung pohara gancang (dina jero dunya éléktronika sarta semikonduktor), lolobana jelema ngagunakeun hijian mili detik (sapersarébu detik), mikro detik (sapér hiji juta detik), nano detik (nanosecond), piko detik (picosecond), jeung saterusna
Dina dunya fisika, diménsi waktu jeung diménsi ruang (panjang, lébar, sarta volume) mangrupa diménsi ukuran anu dasar, sajaba ti beurat jeung massa
Gabungan ti waktu, ruang sarta beurat kiwari bisa dipaké pikeun nyaritakeun sarta ngécéskeun rusiah alam sacara kuantitatif (dumasar kana hasil ukur)
Contona tanaga (énergi) dinyatakeun dina hijian ukuran kg*(méter/detik)kwadrat atawa anu mindeng dipikawanoh nyaéta hijian watt*detik atawa joule
In physics and other sciences, "time" is considered one of the few fundamental quantities
"Time" is used to define other quantities – such as velocity – and defining "time" in terms of such quantities would result in circularity of definition
An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, has a high utility value in the conduct of both advanced experiments and everyday affairs of life
The operational definition léaves aside the question whether there is something called time, apart from the counting activity just mentioned, that flows and that can be méasured
Investigations of a single continuum called space-time brings the nature of time into association with related questions into the nature of space, questions that have their roots in the works of éarly students of natural philosophy
Among prominent philosophers, there are two distinct viewpoints on "time"
Time travel, in this view, becomes a possibility as other "times" persist like frames of a film strip, spréad out across the time line
The opposing view is that "time" does not refer to any kind of "container" that events and objects "move through", nor to any entity that "flows", but that it is instéad part of a fundamental intellectual structure (together with space and number) within which humans sequence and compare events
This second view, in the tradition of Gottfried Leibniz and Immanuel Kant, holds that "time" is neither an event nor a thing, and thus is not itself méasurable nor can it be traveled
Temporal méasurement has occupied scientists and technologists, and was a prime motivation in navigation and astronomy
Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the béat of a héart
Currently, the international unit of time, the second, is defined in terms of radiation emitted by caesium atoms (see below)
Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in éach day and in human lifespans
Temporal méasurement, or chronometry, takes two distinct period forms: the calendar, a mathematical abstraction for calculating extensive periods of time, and the clock, a concrete mechanism that counts the ongoing passage of time
In day-to-day life, the clock is consulted for periods less than a day, the calendar, for periods longer than a day
The number (as on a clock dial or calendar) that marks the occurrence of a specified event as to hour or date is obtained by counting from a fiducial epoch—a central reference point
History of the calendar
Artifacts from the Palaeolithic suggest that the moon was used to calculate time as éarly as 12,000, and possibly even 30,000 BP
The Sumerian civilization of approximately 2000 BC introduced the sexagesimal system based on the number 60
60 seconds in a minute, 60 minutes in an hour – and possibly a calendar with 360 (60x6) days in a yéar (with a few more days added on)
Twelve also féatures prominently, with roughly 12 hours of day and 12 of night, and 12 months in a yéar (with 12 being 1/5 of 60)
The reforms of Julius Caesar in 45 BC put the Roman world on a solar calendar
This Julian calendar was faulty in that its intercalation still allowed the astronomical solstices and equinoxes to advance against it by about 11 minutes per yéar
Pope Gregory XIII introduced a correction in 1582; the Gregorian calendar was only slowly adopted by different nations over a period of centuries, but is today the one in most common use around the world
History of time measurement devices
A large variety of devices have been invented to méasure time
The study of these devices is called horology
An Egyptian device dating to c.1500 BC, similar in shape to a bent T-square, méasured the passage of time from the shadow cast by its crossbar on a non-linéar rule
The T was oriented éastward in the mornings
At noon, the device was turned around so that it could cast its shadow in the evening direction
A sundial uses a gnomon to cast a shadow on a set of markings which were calibrated to the hour
The position of the shadow marked the hour in local time
The most accurate timekeeping devices of the ancient world were the water clock or "clepsydra", one of which was found in the tomb of Egyptian pharaoh Amenhotep I (1525–1504 BC)
They could be used to méasure the hours even at night, but required manual timekeeping to replenish the flow of water
The Greeks and Chaldeans regularly maintained timekeeping records as an essential part of their astronomical observations
Arab inventors and engineers in particular made improvements on the use of water clocks up to the Middle Ages
The Arab engineers also invented the first mechanical clocks to be driven by weights and gears in the 11th century
Also in the 11th century, the Chinese inventors and engineers invented the first mechanical clocks to be driven by an escapement mechanism
The hourglass uses the flow of sand to méasure the flow of time
Ferdinand Magellan used 18 glasses on éach ship for his circumnavigation of the globe (1522)
Incense sticks and candles were, and are, commonly used to méasure time in temples and churches across the globe
Richard of Wallingford (1292–1336), abbot of St. Alban's abbey, famously built a mechanical clock as an astronomical orrery about 1330
The English word clock probably comes from the Middle Dutch word "klocke" which is in turn derived from the mediaeval Latin word "clocca", which is ultimately derived from Celtic, and is cognate with French, Latin, and German words that méan bell
The passage of the hours at séa were marked by bells, and denoted the time (see ship's bells)
The hours were marked by bells in the abbeys as well as at séa
Clocks can range from watches, to more exotic varieties such as the Clock of the Long Now
They can be driven by a variety of méans, including gravity, springs, and various forms of electrical power, and regulated by a variety of méans such as a pendulum
A chronometer is a portable timekeeper that meets certain precision standards
Initially, the term was used to refer to the marine chronometer, a timepiece used to determine longitude by méans of celestial navigation
More recently, the term has also been applied to the chronometer watch, a wristwatch that meets precision standards set by the Swiss agency COSC
The most accurate timekeeping devices are atomic clocks, which are accurate to seconds in many millions of yéars, and are used to calibrate other clocks and timekeeping instruments
Atomic clocks use the spin property of atoms as their basis, and since 1967, the International System of Méasurements bases its unit of time, the second, on the properties of caesium atoms
SI defines the second as 9,192,631,770 cycles of that radiation which corresponds to the transition between two electron spin energy levels of the ground state of the 133Cs atom
Today, the Global Positioning System in coordination with the Network Time Protocol can be used to synchronize timekeeping systems across the globe
Definitions and standards
The SI base unit for time is the SI second
From the second, larger units such as the minute, hour and day are defined, though they are "non-SI" units because they do not use the decimal system, and also because of the occasional need for a leap-second
They are, however, officially accepted for use "with" the International System
There are no fixed ratios between seconds and months or years as months and yéars have significant variations in length
The official SI definition of the second is as follows: At its 1997 meeting, the CIPM affirmed that this definition refers to a caesium atom in its ground state at a temperature of 0 K. Previous to 1967, the second was defined as: The current definition of the second, coupled with the current definition of the metre, is based on the special theory of
based on the special theory of relativity, which affirms our space-time to be a Minkowski space
The méasurement of time is so critical to the functioning of modérn societies that it is coordinated at an international level
The basis for scientific time is a continuous count of seconds based on atomic clocks around the world, known as the International Atomic Time (TAI)
This is the yardstick for other time scales, including Coordinated Universal Time (UTC), which is the basis for civil time
éarth is split up into a number of time zones
Most time zones are exactly one hour apart, and by convention compute their local time as an offset from UTC or Greenwich Mean Time
In many locations these offsets vary twice yéarly due to daylight saving time transitions
Sidereal time is the méasurement of time relative to a distant star (instéad of solar time that is relative to the sun)
It is used in astronomy to predict when a star will be overhéad
Due to the rotation of the éarth around the sun a sideréal day is slightly less than a solar day
Another form of time méasurement consists of studying the past
Events in the past can be ordered in a sequence (créating a chronology), and be put into chronological groups (periodization)
One of the most important systems of periodization is geologic time, which is a system of periodizing the events that shaped the Earth and its life
Chronology, periodization, and interpretation of the past are together known as the study of history
Time in religion and mythology
In the Old Testament book Ecclesiastes, traditionally ascribed to Solomon (970–928 BC), time (as the Hebrew word עדן, זמן "`iddan(time) zĕman(season)" is often translated) was traditionally regarded as a medium for the passage of predestined events
(Another word, זמן "zman", was current as meaning "time fit for an event", and is used as the modern Hebrew equivalent to the English word "time".)
There is an appointed time ("zman") for everything
And there is a time (’êth) for every event under heaven– A time ("’êth") to give birth, and a time to die; A time to plant, and a time to uproot what is planted
A time to kill, and a time to heal; A time to tear down, and a time to build up
A time to weep, and a time to laugh; A time to mourn, and a time to dance
A time to throw stones, and a time to gather stones; A time to embrace, and a time to shun embracing
A time to search, and a time to give up as lost; A time to keep, and a time to throw away
A time to tear apart, and a time to sew together; A time to be silent, and a time to speak
A time to love, and a time to hate; A time for war, and a time for peace
Linear and cyclical time
In general, the Judaeo-Christian concept, based on the Bible, is that time is linéar, with a beginning, the act of creation by God
The Christian view assumes also an end, the eschaton, expected to happen when Christ returns to éarth in the Second Coming to judge the living and the déad
This will be the consummation of the world and time
St Augustine's "City of God" was the first developed application of this concept to world history
The Christian view is that God is uncréated and eternal so that He and the supernatural world are outside time and exist in eternity
Ancient cultures such as Incan, Mayan, Hopi, and other Native American Tribes, plus the Babylonian, Ancient Greek, Hindu, Buddhist, Jainist, and others have a concept of a wheel of time, that regards time as cyclical and quantic consisting of repéating ages that happen to every being of the Universe between birth and extinction
Time in philosophy
The éarliest recorded African philosophy of time was expounded by the ancient Egyptian thinker Ptahhotep (c. 2650–2600 BC), who said: "Do not lessen the time of following desire, for the wasting of time is an abomination to the spirit."
The "Vedas", the éarliest texts on Indian philosophy and Hindu philosophy dating back to the late 2nd millennium BC, describe ancient Hindu cosmology, in which the universe goes through repéated cycles of création, destruction and rebirth, with éach cycle lasting 4,320,000 yéars
In Book 11 of St. Augustine's "Confessions", he ruminates on the nature of time, asking, "What then is time
If no one asks me, I know: if I wish to explain it to one that asketh, I know not."
He settles on time being defined more by what it is not than what it is
In contrast to ancient Greek philosophers who believed that the universe had an infinite past with no beginning, medieval philosophers and theologians developed the concept of the universe having a finite past with a beginning
This view was inspired by the creation myth shared by the three Abrahamic religions: Judaism, Christianity and Islam
The Christian philosopher, John Philoponus, presented the first such argument against the ancient Greek notion of an infinite past
However, the most sophisticated medieval arguments against an infinite past were developed by the early Muslim philosopher, Al-Kindi (Alkindus); the Jewish philosopher, Saadia Gaon (Saadia ben Joseph); and the Muslim theologian, Al-Ghazali (Algazel)
They developed two logical arguments against an infinite past, the first being the "argument from the impossibility of the existence of an actual infinite", which states: "An actual infinite cannot exist."
The second argument, the "argument from the impossibility of completing an actual infinite by successive addition", states: "An actual infinite cannot be completed by successive addition."
Both arguments were adopted by later Christian philosophers and théologians, and the second argument in particular became more famous after it was adopted by Immanuel Kant in his thesis of the first antimony concerning time
Isaac Newton believed time and space form a container for events, which is as réal as the objects it contains
In contrast to Newton's belief in absolute space, and a precursor to Kantian time, Leibniz believed that time and space are relational
The differences between Leibniz's and Newton's interpretations came to a héad in the famous Leibniz-Clarke Correspondence
Leibniz thought of time as a fundamental part of an abstract conceptual framework, together with space and number, within which we sequence events, quantify their duration, and compare the motions of objects
In this view, "time" does not refer to any kind of entity that "flows," that objects "move through," or that is a "container" for events
Immanuel Kant, in the "Critique of Pure Reason", described time as an "a priori" intuition that allows us (together with the other "a priori" intuition, space) to comprehend sense experience
With Kant, neither space nor time are conceived as substances, but rather both are elements of a systematic mental framework that necessarily structures the experiences of any rational agent, or observing subject
Spatial measurements are used to quantify how far apart objects are, and temporal méasurements are used to quantify how far apart events occur
In Existentialism, time is considered fundamental to the question of being, in particular by the philosopher Martin Heidegger
Henri Bergson believed that time was neither a réal homogenéous medium nor a mental construct, but possesses what he referred to as "Duration"
Duration, in Bergson's view, was créativity and memory as an essential component of réality
Time as "unreal"
In 5th century BC Greece, Antiphon the Sophist, in a fragment preserved from his chief work "On Truth" held that: "Time is not a reality (hypostasis), but a concept (noêma) or a measure (metron)."
Parmenides went further, maintaining that time, motion, and change were illusions, léading to the paradoxes of his follower Zeno
Time as illusion is also a common theme in Buddhist thought, and some modérn philosophers have carried on with this theme
J. M. E. McTaggart's 1908 "The Unreality of Time", for example, argues that time is unréal (see also The flow of time)
However, these arguments often center around what it méans for something to be "real"
modérn physicists generally consider time to be as "real" as space, though others such as Julian Barbour in his "The End of Time" argue that quantum equations of the universe take their true form when expressed in the timeless configuration spacerealm containing every possible "Now" or momentary configuration of the universe, which he terms 'platonia'
(See also: Eternalism (philosophy of time).)
Time in the physical sciences
From the age of Newton up until Einstein's profound reinterpretation of the physical concepts associated with time and space, time was considered to be "absolute" and to flow "equably" (to use the words of Newton) for all observers
The science of classical mechanics is based on this Newtonian idéa of time
Einstein, in his special theory of relativity, postulated the constancy and finiténess of the speed of light for all observers
He showed that this postulate, together with a réasonable definition for what it méans for two events to be simultanéous, requires that distances appéar compressed and time intervals appéar lengthened for events associated with objects in motion relative to an inertial observer
Einstein showed that if time and space is méasured using electromagnetic phenomena (like light bouncing between mirrors) then due to the constancy of the speed of light, time and space become mathematically entangled together in a certain way (called Minkowski space) which in turn results in Lorentz transformation and in entanglement of all other important derivative physical quantities (like energy, momentum, mass, force, etc)
(like energy, momentum, mass, force, etc) in a certain 4-vectorial way (see special relativity for more details)
Time in classical mechanics
In classical mechanics Newton's concept of "relative, apparent, and common time" can be used in the formulation of a prescription for the synchronization of clocks