Do bulletproof vests protect against punches and hammer blows?

[tade]

i was wondering about this, because I learned that those vests don't protect against knives.

 

[phinds]

They protect against force trauma of any kind in the same way, by spreading the impact out over a large area. I doubt that would do much good against a really hard sledge-hammer blow since it would like still crush your chest, just as they won't protect against broken ribs if you are hit with a very hefty, but soft slug.