1. Isisindo (w)
Amandla adonsela phansi, noma ngokuvamile afushaniswa njengesisindo, amandla adonsela phansi asebenza entweni enobunzima. Uphawu lwamandla adonsela phansi ngu-w, olumele isisindo.
Ifomula yokubala amandla adonsela phansi ivela kufomula Umthetho wesibili kaNewton :
F = ma
Kusetshenziswa ukubala amandla adonsela phansi:
w = mg
I-Keterangan :
F = amandla (iyunithi yamazwe ngamazwe = iNewton)
w = amandla adonsela phansi (iyunithi yamazwe ngamazwe = iNewton)
m = isisindo sento (amayunithi aphesheya = kg)
kuze = ukusheshisa (iyunithi yamazwe ngamazwe = m/s2)
g = ukusheshisa ngenxa yamandla adonsela phansi (amayunithi aphesheya = m/s2)
2. Amandla Ajwayelekile
Amandla avamile amandla asebenza ezintweni ezimbili ezithintanayo, lapho isiqondiso samandla avamile siqonde ngqo ebusweni bendawo yokuxhumana.
Bheka into emile phezu kwetafula. Isisindo noma amandla adonsela phansi nawo asebenza entweni. Izinto aziwi ngokukhululeka njengesithelo esiwa esihlahleni ngoba kukhona amandla avamile alinganisela amandla adonsela phansi. Amandla adonsela phansi kanye namandla avamile anobukhulu obufanayo kodwa aphambene ngakho amandla aphumelayo asebenza entweni ayi-zero.
