[Trig]

If a 2x4 was moving at 10 mph and hit me, I would not fall over. However, if a car hit me traveling 10 mph, I would most certainly fall over.

It seems that the mass behind the item striking me has something to do with the way my body will react when struck.

I've heard Yoda talk about "effective mass" being more important than clubhead speed. But I must confess, it's not a concept I claim to understand.