Iphepha Lefiziksi Ngemithetho KaNewton
I-Pendahuluan
I-physics iyigatsha lesayensi yemvelo elifunda izenzakalo nokuziphatha kwendawo yonke ngokubuka, ukulinganisa, kanye nokwakhiwa kwemithetho esebenzayo ngokuvamile. Esinye sezisekelo eziyinhloko ze-physics yakudala yi-Newton's Laws of Motion. Le mithetho yasungulwa nguSir Isaac Newton ngekhulu le-17 futhi isebenza njengesisekelo sokuqonda ukuthi izinto zihamba kanjani nokuthi amandla athonya kanjani izinguquko kulokho kunyakaza. Naphezu kokuvela kwe-relativity yanamuhla kanye ne-quantum mechanics, i-Newton's Laws isasebenza kakhulu ekuchazeni izenzakalo ezahlukahlukene zansuku zonke, ikakhulukazi esikalini sezinto ezihamba ngesivinini esincane kakhulu kunesivinini sokukhanya.
Imithetho kaNewton ayiyona nje isethi yamafomula, kodwa iwuhlaka lwesayensi lokucabanga ngobudlelwano phakathi kwamandla, ubukhulu, kanye nokusheshisa. Ukusetshenziswa kwayo kukhulu, kusukela ekubaleni ukuhamba kwezimoto kanye nokwakhiwa kwebhuloho kuya ekuhlaziyweni kwezemidlalo ngisho nasebuchwephesheni bezindiza kanye nesikhala. Leli phepha lizoxoxa ngokuhlelekile ngemithetho emithathu kaNewton, imiqondo yamandla kanye nobukhulu, kanye nezibonelo zokusetshenziswa kwayo ekuphileni kwansuku zonke.
Imiqondo Eyisisekelo: Amandla, Isisindo, Nokunyakaza
Ngaphambi kokuxoxa ngemithetho emithathu kaNewton, kubalulekile ukuqonda imiqondo eyinhloko ehilelekile. Amandla ayindlela yokucindezela noma yokudonsa engashintsha isimo sokunyakaza kwento. Amandla anobukhulu kanye nesiqondiso, okwenza kube yi-vector quantity. Iyunithi yamandla ye-SI yiNewton (N), echazwa njengamandla adingekayo ukuze kunikezwe ukusheshisa okungu-1 m/s² esisindweni esingu-1 kg.
Isisindo siyisilinganiso sokungaguquguquki kwento, okungukuthi, ukuthambekela kwayo ekulondolozeni isimo sayo sokunyakaza. Uma isisindo sento sikhulu, kuba nzima kakhulu ukusheshisa noma ukuma. Isisindo sihlukile kwesisindo. Isisindo singamandla adonsela phansi asebenza entweni, ngakho-ke kuncike ekusheshiseni kwamandla adonsela phansi kwendawo.
Ukunyakaza ku-physics kuvame ukufundwa ngesikhundla samanani, ijubane, kanye nokusheshisa. Ijubane libonisa ukuthi isikhundla sishintsha ngokushesha kangakanani maqondana nesikhathi, kuyilapho ukusheshisa kubonisa ushintsho lwejubane ngesikhathi ngasinye. Imithetho kaNewton ixhumanisa amandla nokusheshisa, ngaleyo ndlela ihlinzeka ngebhuloho phakathi kwembangela (amandla) kanye nomphumela (ushintsho ekunyakazeni).
Umthetho Wokuqala KaNewton (Umthetho Wokungabi Nandaba)
UMthetho Wokuqala KaNewton uthi: "Into izohlala iphumule noma ihambe emgqeni oqondile ngesivinini esingaguquki uma amandla asebenzayo kuyo engu-zero." Lokhu kusho ukuthi uma kungekho mandla asebenzayo athinta into, into ngeke ibhekane noshintsho lwejubane.
Umqondo oyinhloko kulo mthetho yi-inertia. I-Inertia ichaza ukuthi kungani abagibeli bezimoto besunduzelwa phambili lapho imoto ibhuleka ngokuzumayo. Njengoba imoto yehlisa ijubane, umzimba womgibeli uvame ukugcina ukunyakaza kwawo phambili ngenxa ye-inertia. Yingakho amabhande esihlalo ebaluleke kangaka, njengoba enikeza amandla avimba umzimba ukuthi uqhubeke nokuya phambili.
Esinye isibonelo into esetafuleni. Into ihlala iphumule ngoba awekho amandla avundlile abangela ukuthi ihambe; amandla adonsela phansi adonsela phansi kanye namandla aphezulu etafuleni ayalingana, ngakho amandla aphumelayo ayi-zero. Ngakho-ke, umthetho wokuqala ugcizelela ukuthi ushintsho ekuhambeni lwenzeka kuphela uma kukhona amandla aphumelayo angewona u-zero.
Umthetho Wesibili KaNewton (Ubudlelwano Phakathi Kwamandla, Ubuningi, Nokusheshisa)
UMthetho Wesibili kaNewton uwumgogodla wezindlela zakudala futhi uthi: "Ukusheshisa kwento kuhambisana namandla asebenzayo kuyo futhi kuhambisana nobunzima bayo ngokuphambene." Ngokwezibalo, yakhiwe kanje:
ΣF = m · a
Lapha, u-ΣF ungamandla aphumayo (N), u-m uyisisindo (kg), kanti u-a uyisivinini (m/s²). Le fomula ibonisa amaphuzu amabili abalulekile. Okokuqala, uma amandla asetshenziswa entweni enobunzima obungaguquki, kulapho ukusheshisa okuphumayo kuba kukhulu. Okwesibili, ngamandla afanayo, into enobunzima obukhulu izobhekana nokusheshisa okuncane.
Isibonelo, ukusunduza inqola yokuthenga engenalutho kulula kunokusunduza egcwele. Inqola egcwele inobunzima obukhulu, ngakho-ke ukusheshisa kuncane ngenxa yamandla afanayo okusunduza. Izibonelo zezemidlalo nazo zicacile: ibhola lethenisi kulula ukulisheshisa kunebhola le-bowling ngoba ubunzima balo buncane kakhulu.
UMthetho Wesibili KaNewton uphinde usize ekuhlaziyeni amandla asebenza entweni, njengokungqubuzana, ukucindezeleka entanjeni, amandla entwasahlobo, kanye namandla adonsela phansi. Lapho kuxazulula izinkinga, umdwebo womzimba okhululekile uvame ukusetshenziswa ukumaka wonke amandla asebenzayo ukuze amandla avelayo abalwe kahle.
Umthetho Wesithathu KaNewton (Isenzo Nokusabela)
UMthetho Wesithathu kaNewton uthi: "Kuyo yonke into, kukhona ukusabela okulinganayo nokuphambene." Lokhu kusho ukuthi uma into A isebenzisa amandla entweni B, khona-ke into B isebenzisa amandla alinganayo entweni A kodwa ngakolunye uhlangothi.
Lo mthetho uvame ukungaqondwa kahle ngoba abantu bacabanga ukuthi isenzo nokusabela kuyahlukanisana. Eqinisweni, la mandla amabili asebenza ezintweni ezimbili ezihlukene, ngakho awahlukani entweni efanayo. Isibonelo, lapho umuntu emi phansi, izinyawo zakhe zikhipha amandla phansi (isenzo), kanti phansi kukhipha amandla ajwayelekile aphezulu ezinyaweni zakhe (ukusabela). Ngenxa yokuthi amandla okusabela avela phansi makhulu ngokwanele ukulinganisela isisindo sakhe, umuntu angama ngaphandle kokuwa.
Esinye isibonelo esaziwa kakhulu ukunyakaza kwerokhethi. Irokhethi idubula igesi emuva ngesivinini esikhulu (isenzo), bese igesi iphoqa phambili irokhethi (ukusabela), iqhube irokhethi iye phezulu. Isimiso esifanayo sisebenza ebhaluni elishiywe lingaboshiwe: umoya uyaphuma ohlangothini olulodwa bese ibhaluni liphushwa ohlangothini oluphambene.
Ukusetshenziswa Kwemithetho KaNewton Empilweni Yansuku Zonke
Imithetho kaNewton ingatholakala emisebenzini eminingi. Ekuthuthweni, ukwakheka kwemoto kubheka amandla ahlukahlukene njengamandla enjini, ukumelana nomoya, kanye nokungqubuzana kwamathayi. Lapho imoto ijika, kudingeka amandla aphakathi nendawo ukuze kulondolozwe indlela eyindilinga yemoto; uma ukungqubuzana kunganele, imoto ingagudluza.
Kobunjiniyela, ukwakhiwa kwezakhiwo namabhuloho kudinga ukuhlaziywa kwebhalansi yamandla (uMthetho Wokuqala kaNewton). Izakhiwo kumele zakhiwe ngendlela yokuthi amandla nezikhathi eziphumayo ezindaweni ezithile zingabangeli ukuwohloka. Kubuchwepheshe bemishini esindayo, uMthetho Wesibili kaNewton usetshenziswa ukunquma amandla adingekayo ukuze umshini uphakamise noma uhambise umthwalo othize.
Kwezemidlalo, abasubathi basebenzisa umthetho wokusabela ngesenzo. Umgijimi usunduza phansi, okusunduza umgijimi phambili. Umbhukudi usunduza emanzini, okusunduza umbhukudi phambili. Uma amandla okudonsa esebenza kahle, kulapho ukusheshisa okuvelayo kuba kukhulu khona.
Ukulinganiselwa Kwemithetho KaNewton
Nakuba iwusizo kakhulu, imithetho kaNewton inemikhawulo. Inembile kakhulu ezintweni ze-macroscopic ngesivinini esiphansi. Ngesivinini esisondela esivinini sokukhanya, inkolelo-mbono ka-Einstein yokuhlobana iba neqiniso kakhulu ngoba isisindo nesikhathi esisebenzayo asisaphelele. Ngesilinganiso sama-athomu nezinhlayiya ezingaphansi kwe-atomic, i-quantum mechanics iyadingeka ngoba ukuziphatha kwezinhlayiya akunakuchazwa kuphela ngamandla akudala kanye nezindlela zokuhamba.
Kodwa-ke, ezinkingeni eziningi zansuku zonke kanye nezicelo eziningi zobunjiniyela, iMithetho kaNewton iseyindlela eyinhloko ngoba ilula, iyasebenza, futhi inembe ngokufanele.
Isiphetho
Imithetho kaNewton iyisisekelo esibalulekile ku-physics yakudala echaza ubudlelwano phakathi kwamandla nokunyakaza. Umthetho Wokuqala kaNewton uthi into izogcina isimo sayo sokunyakaza uma amandla aphumayo engu-zero. Umthetho Wesibili kaNewton uchaza ukuthi ukusheshisa kuhambelana ngqo namandla aphumayo futhi kuhambisana ngokuphambene nobunzima, okwakhiwe njengo-ΣF = m·a. Umthetho Wesithathu kaNewton ugcizelela isimiso sokusabela kwesenzo, ukuthi wonke amandla ahlala enomlingani olingana ngobukhulu futhi ophambene.
Ngokuqonda le mithetho emithathu, singahlaziya izinhlobonhlobo zezenzakalo zemvelo nezobuchwepheshe, kusukela ekunyakazeni okulula ekuphileni kwansuku zonke kuya ekwakhiweni kwemishini nezimoto. Naphezu kokulinganiselwa kwayo ezimweni ezimbi kakhulu, iMithetho kaNewton isasebenza futhi yakha enye yempumelelo enkulu emlandweni wesayensi.
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Uma ufisa, ngingangeza uhlu lwezincwadi, isandulela, noma ngidale inguqulo "yefomethi yesikole" (enesizinda, isitatimende senkinga, izinhloso, ingxoxo, kanye nesiphetho).
