Vector2 VelocityVectorDelta(GameObject parent, int framePlus)
{
SystemObject parentSystemObject = parent.GetComponent <SystemObject>();
float pull = parentSystemObject.gravityPull;
Vector2 parentPosition = parentSystemObject.PositionAtTime(framePlus);
Vector2 myPosition = PositionAtTime(framePlus);
float invSquare = 1.0f / (Vector2.Distance(parentPosition, myPosition) * Vector2.Distance(parentPosition, myPosition));
Vector2 normalizedDirection = (parentPosition - myPosition).normalized;
return(new Vector2(normalizedDirection.x * pull * invSquare, normalizedDirection.y * pull * invSquare));
}