Answer: Multiple ethnic groups
Step-by-step explanation:
A centrifugal force in the context of geography refers to forces, factors or events that act to cause disunity and pull people apart.
In the case of the former Yugoslavia and the surrounding Balkans, the centrifugal force would be the existence of multiple ethnic groups in one country and region which included the Serbs, Croats, Albanians, Slovenians, Macedonians, etc.
These groups struggled for dominance especially the Serbs and it led to conflict as the other groups refused. Eventually Yugoslavia was broken up.