Umthetho Wokuqala KaNewton ithi yonke into ephumule izohlala iphumule noma ... noma iphumule ... berukunyakaza okuqondile okufanayo izoqhubeka nokuhamba emgqeni oqondile ngesivinini esingaguquki uma amandla aphelele, noma amandla aphumelayo asebenza entweni, elingana no-zero. Isitatimende sezibalo somthetho wokuqala kaNewton:
Cabanga ngento ekuzungezile, njengetafula, idwala, noma yini enye. Itafula eliphumule lizohlala liphumule ngaphandle kokuthi lisuswe noma lifakwe amandla angaphandle, njengokusunduzwa noma ukudonswa. Kunjalo nangezinye izinto eziphumule.
Awekho yini amandla asebenza etafuleni noma edwaleni noma kunoma iyiphi enye into ephumule? Kukhona amandla asebenza entweni, kodwa isamba sawo wonke amandla asebenza entweni noma amandla aphumelayo silingana no-zero. Amandla asebenza entweni ephumule yi- gravity kanye namandla avamile . Isiqondiso samandla adonsela phansi siqonde emhlabathini sibheke enkabeni yomhlaba, isiqondiso samandla avamile siqonde emhlabathini. Ubukhulu bala mandla amabili buyafana kodwa buphambene ngakho amandla aphumelayo alingana no-zero.
Kuthiwani ngento ehamba ngomugqa oqondile ngesivinini esingaguquki? Ukuze kucaciswe lokhu, ake sithi ucindezela into, njengengcezu yensimbi, phansi. Ngemva kokusunduzwa, ingcezu iyehla ijubane bese ima ngenxa yokungqubuzana . Ukuze wenze ingcezu iqhubeke noma ihambe isikhathi eside, udinga ukwenza ingcezu ihambe kahle. Uma ingcezu ibushelelezi, ingcezu izohamba kakhulu. Uma ingcezu ibushelelezi ngokuphelele futhi ingenakho ukungqubuzana, ingcezu ibizoqhubeka ihambe futhi ingami. Awekho yini amandla asebenza engcezu yensimbi ehamba phansi ebushelelezi ngokuphelele? Kukhona amandla asebenza engcezu yensimbi, okungukuthi amandla adonsela phansi kanye namandla ajwayelekile. Lawa mandla amabili asebenza ngokuqondile futhi awathinti ukunyakaza kwengcezu ohlangothini oluvundlile.
