Isihloko mayelana nomthetho kaNewton wokunyakaza
1. Incazelo yamandla
Amandla yinto ebangela ukuba izinto zisheshise. Ngamanye amazwi, amandla yinto ehambayo, emisa, noma eshintsha indlela yokunyakaza kwento. Amandla ayinani le-vector, ngakho-ke, anobukhulu kanye nesiqondiso. Uphawu lwamandla ngu-F (Amandla). U-F uphawu olujwayelekile lwamandla. Kunezinhlobo eziningana zamandla futhi akuwona wonke amandla anophawu u-F. Iyunithi yesistimu yamazwe ngamazwe ingu-kg m/s2 aka Newton.
2. Incazelo yamandla aphelele
Amandla aphumayo (ΣF) yisamba sawo wonke amandla asebenza entweni. Amandla ayinani levektha, ngakho-ke amandla aphelele abalwa ngokusekelwe emthethweni wokwengeza ivektha.
Amandla aphelele = amaNewton ayi-10, isiqondiso samandla aphelele ngakwesokudla.
Amandla aphelele = amaNewton ayi-8, isiqondiso samandla aphelele ngakwesokudla.
Amandla aphelele = 0
Amandla aphelele = 0
3. Imithetho kaNewton yokunyakaza
Imithetho kaNewton yokuhamba yimithetho yefiziksi mayelana nokuhamba kwento ephakanyiswe yisazi sefiziksi saseNgilandi, u-Isaac Newton.
3.1 Umthetho Wokuqala KaNewton
Umthetho Wokuqala KaNewton uthi yonke into ephumule kufanele ihlale iphumule, noma yonke into ehamba iqonde ngesivinini esingaguquki
izoqhubeka nokuhamba iqonde ngesivinini esingaguquki uma amandla aphelele asebenza entweni engu-zero.
ΣF = 0
Lesi sibalo siyisitatimende sezibalo esivela emthethweni wokuqala kaNewton.
Bona into ekuzungezile, njengetafula noma itshe noma iyiphi into. Itafula eliphumule lizohlala liphumule uma lingashukunyiswa noma linganikezwanga amandla angaphandle njengokucindezela noma ukudonsa. Awekho yini amandla asebenza ematafuleni noma emadwaleni noma ezintweni eziphumule? Kukhona amandla asebenza entweni, kodwa isamba sawo wonke amandla asebenza entweni noma amandla aphelele angu-zero. Amandla asebenza ezintweni ezisebusweni bamaplanethi afana nomhlaba adonsela phansi (w) kanye namandla avamile (N). Isiqondiso samandla adonsela phansi siqonde enkabeni yomhlaba, isiqondiso samandla avamile siqonde phezulu. Ubukhulu bala mandla amabili buyafana, kodwa anohlangothi oluphambene, ngakho-ke amandla aphelele alingana no-zero.
Kuthiwani ngezinto ezihamba ziqonde ngesivinini esingaguquki? Ukuze kucaciswe le nkinga, ake sithi ucindezela into, isibonelo, ucezu lwensimbi, ebusweni bephansi. Ngemva kokusunduzwa, insimbi yehlisa ijubane futhi yema ngenxa yokungqubuzana. Ukuze izingcezu zensimbi zihambe ziqhubeke noma zibe zinde, kufanele ulungise ubuso bephansi kanye nobuso bepuleti lensimbi. Uma ubuso bephansi bubushelelezi futhi kungekho ukungqubuzana, ipuleti lensimbi lizoqhubeka nokuhamba futhi lingami. Awekho yini amandla asebenza epuletini lensimbi elihamba ebusweni bephansi eliphelele, elibushelelezi? Kukhona amandla asebenza ezipuletini zensimbi, okungukuthi amandla adonsela phansi kanye namandla avamile. Womabili la mandla asebenza ngendlela eqondile futhi awathinti ukunyakaza kwamapuleti ensimbi ohlangothini oluvundlile uma phansi lubushelelezi.
3.2 Umthetho Wesibili KaNewton
Umthetho Wesibili kaNewton uthi uma amandla aphelele asebenza entweni engalingani no-zero, khona-ke into izoshesha. Ubukhulu bokusheshisa buhambisana nobukhulu bamandla aphelele futhi buhambisana nobunzima bento. Isiqondiso sokusheshisa sifana nesiqondiso samandla aphelele.
ΣF = ma
ΣF = amandla aphelele (kg m/s2), m = isisindo (kg), a = ukusheshisa (m/s2)
Isibalo 1.2 siyisitatimende sezibalo esivela emthethweni wesibili kaNewton.
Uma ukusheshisa kulingana no-zero (a = 0) khona-ke i-equation 1.2 iyashintsha ibe yi-equation 1.1. Ngakho-ke, umthetho wokuqala kaNewton uyisibonelo esikhethekile somthetho wesibili kaNewton. Ngokusekelwe ku-equation 1.2 kuphethwa ngokuthi lapho amandla emakhulu, ukusheshisa kukhulu. Ngokuphambene nalokho, lapho isisindo sikhulu, ukusheshisa kuncane. Ubudlelwano phakathi kwamandla, isisindo, kanye nokusheshisa buqondwa kangcono ngemva kokwenza ukuhlolwa mayelana nalokhu.
Inkinga yesampula 1:
Nquma ubukhulu kanye nesiqondiso sokusheshisa kwezinto ngokusekelwe esithombeni esingenhla…
Isixazululo:
ΣF = ma
4 kg m/s2 = (1 kg) a
a = 4 kg m/s2 : 1 kg = 4 m/s2
Ubukhulu bokusheshisa = 4 m/s2, indlela yokusheshisa ngakwesokudla.
Inkinga yesampula 2:
Nquma ubukhulu kanye nesiqondiso sokusheshisa ngokusekelwe esithombeni esingenhla ...
Isixazululo:
ΣF = ma
4 kg m/s2 – 1 kg m/s2 = (1 kg) a
3 kg m/s2 = (1 kg) a
a = 3 kg m/s2 : 1 kg
a = 3 m/s 2
Ubukhulu bokusheshisa = 3 m/s2, indlela yokusheshisa ngakwesokudla.
3.2.1 Isisindo (w)
Isisindo amandla adonsela phansi asebenza entweni enkulu.
ΣF = ma
w = mg
Isibalo 1.3 yisibalo sokubala isisindo sento.
w = isisindo (kg m/s2), m = isisindo (kg), g = ukusheshisa kwamandla adonsela phansi (m/s2). Ubukhulu bokusheshisa kwamandla adonsela phansi (g) ebusweni bomhlaba bungu-9.8 m/s2Ukuze kube lula ukubala, u-g uzungezwa ku-10 m/s2.
3.2.2 Amandla ajwayelekile (N)
Amandla avamile amandla asebenza ezintweni ezimbili ezithintanayo, lapho isiqondiso samandla avamile siqonde ngqo ebusweni bendiza yokuthinta.
Bheka izinto ezisesengaphezulu kobuso betafula. Amandla adonsela phansi noma isisindo nawo asebenza entweni. Izinto aziwi ngokukhululeka njengesithelo esiwa esihlahleni ngoba kukhona amandla ajwayelekile. Isisindo (w) kanye nesijwayelekile (N) ziyafana kodwa ziphambene ngakho amandla aphelele entweni ayi-zero.
ΣF = 0
N – w = 0
N = w
3.3 Umthetho Wesithathu KaNewton
Umthetho wesithathu kaNewton uthi uma into 1 inika amandla into 2, khona-ke into 2 inika amandla into 1. Amandla amabili afana, kodwa isiqondiso samandla amabili siphambene. Amandla elilodwa libizwa ngokuthi isenzo, elinye libizwa ngokuthi ukusabela.
Isenzo sika-F = – ukusabela kuka-F
Isibalo 1.3 yisitatimende sezibalo esivela emthethweni wesithathu kaNewton. Uphawu olubi kusibalo 1.3 luchaza indlela amandla aqondiswa ngayo.
Zama ukuze uqonde kangcono umthetho wesithathu kaNewton. Uma une-skateboard, cindezela udonga umi ku-skateboard. Ngemva kokusunduza udonga, i-skateboard iya emuva. Isiqondiso samandla akho sibheke phambili, kanti isiqondiso se-skateboard sibheke emuva.
Lokhu kubonisa ukuthi udonga luyakuphoqelela. Uma ucindezela udonga, ngesikhathi esifanayo, udonga luyakusunduza. Amandla akho okusunduza asebenza odongeni, kuyilapho amandla okusunduza odongeni esebenza kuwe. Womabili la mandla ayafana kodwa ahlukene. Ungabiza amandla elilodwa ngokuthi isenzo kanti elinye ngokuthi ukusabela.
Olunye uvivinyo olungenziwa ukufutha ibhaluni lerabha bese kuthi ngemva kokuba ibhaluni lerabha likhule ngoba ligcwele umoya, likhulule ibhaluni. Ngemva kokukhululwa, ibhaluni "liyandiza". Isiqondiso sokunyakaza kwebhaluni siphambene nesiqondiso sokuphuma komoya ebhaluni. Ungakuchaza kanjani lokhu?
Uma umlomo webhaluni ukhishwa, ibhaluni likhipha umoya. Ngesikhathi esifanayo, umoya uphinde uphushe ibhaluni. Amandla omoya acindezela ibhaluni abangela ukuba ibhaluni lindize. Amandla ebhaluni ayasebenza edlala, amandla omoya asebenza ebhaluni. Amandla amabili afana, kodwa isiqondiso siphambene.
Bheka isithombe 2 bese usiqhathanisa nesithombe 3. Amandla avamile asebenza entweni (N) amandla anikezwa ubuso obuyisicaba, njengobuso betafula. Ngesikhathi esifanayo, izinto nazo zinikeza amandla ebusweni betafula (N'). Womabili la mandla avamile (N no-N') anobukhulu obufanayo, kodwa asemaceleni ahlukene futhi asebenza ezintweni ezahlukene. Ngokungafani no-w no-N abanobukhulu obufanayo futhi abasebenza entweni efanayo. Ngakho-ke u-N no-N 'bangamandla okusabela kwesenzo.
