No, you don't understand. That's just an example in CSS. In fact that physics happens in all HL2-engine games and FEAR and some other games --- an entity which has huge mass will be rejected by an entity which has tiny mass but their rejectile distances are the same! In CSS, sometimes I just hit a little wine bottle then I'm rejected back a long distance! That's not real. I has huge mass, that little bottle has tiny mass, we impacts, the bottle should gain more momentum than me because I have more mass! ft=mv or something else?
and sorry for my English in Physics