Accurate knocback

so my game heavily involves realistic physics and i was wondering how i can make a part get knocbacked for a specific amount of studs? like set the properties of the body velocity properly such that it would make a static object move exactly in those may studs?

i am doing math to get the knocback. very unreadable math.

((speed/areawisething)/(volume(part)*ratiomod.lerp(setings.mArmourdense,setings.MArmourdense, ratiomod.reverselerp(setings.mArmourdense+1,setings.MArmourdense/6+setings.healthsbase[part.Name], part:GetAttribute("Health"))))  )  

i also testd it, the math works