Ta'n siyraghey, ny bieauaghey keayrtyn, ny chormid arraghee t'ayn tra dy vel tappeeys ny bieauid nhee arraghey.

Ta formley ry-gheddin lesh y mooad d'obbraghey magh myr ta:

bieauaghey = arraghey bieauid / am gowit gys y bieauid d'arraghey

ny

'Sy chooish shoh

a = bieauaghey
u = bieauid hoshee
v = bieauid yerrinagh
t = am gowit

T'ad ny h-unnidyn ta gowit lesh y bieauaghey na meaderyn 'sy tullagh ny kilomeaderyn 'syn oor myr ta m/s as km/h.