"Bulletproof" vests are designed to stop bullets. Nothing more. They do so by spreading the force out over a larger area. You can imagine it like a trapeze safety net....only the holes in the netting are smaller. A person falling hits the net and, being larger than the holes, is caught and stopped. If you dropped a baseball onto that same net, however, it would go through the holes in the net easily.
Standard "bulletproof" vests, being made from layers of fabric with holes through them (microscopic netting), don't work against any pointed or cutting object....icepicks, knives, arrows, razors etc...and the makers make sure you know that. The points go through the holes and they spread the fibers open. You can visit any website of any body armor manufacturer (do a web search) and they will tell you that.
Armor designed to stop pointed objects and cutting is called "special purpose body armor" and in most cases won't stop a bullet. Prison guards wear "special purpose" armor that stops stabbings and cuttings but won't stop most any bullet since they aren't threatened by them.
Armor that *does* stand up to both bullets and stabbing is called "multi-threat armor" and is more rare. It tends to be heavier, thicker, and a lot harder to wear comfortably.
Armor made to stop one threat always tends to be flawed in stopping other threats. Old plate armor could stop a cut etc but wasntt proof against impact weapons like maces and flails. Chain mail could stop any cut/slash, but was easily defeated by stabbing/impact weapons etc. Padded/quilted armor that was designed to stop injuries from maces and flails was easily cut etc. To make armor that stopped ALL threats, you ended up with a guy with a hundred pounds of armor that can't fight effectively....the same holds true to this day.
In response to JD (yet again):
"""So YES, a bullet-proof vest will stand up to an arrow NOTE **** I CHALLENGE ANYONE ON YAHOO ANSWERS TO PROVE THAT AN ARROW HAS PENETRATED BODY ARMOR. THE PARTIES THAT CLAIM IT , HAVE NO DOCUMENTATION TO PROVE THIS HAS EVER HAPPENED.... """
To "prove this has ever happened" is garbage semantics, bud. Simply more of you twisting words. To "prove that it *can* happen", I'll simply copy and paste a paragraph off of a well-known dealer's site:
"Vests provide excellent protection against most SLASHING attacks - but are not as effective against THRUSTING attacks with daggers or ice picks.
Pointed and streamlined objects such as an ice picks, arrowheads, and knives, etc. can penetrate if THRUST with enough force. Because of the “pointedness” they can get in-between the Kevlar® or aramid fiber weave to penetrate. We do offer some of our models with a special aramid weave to provide stab-resistant AND ballistic protection. Also you can add Stab Resistant Inserts to regular ballistic vests."
There is a reason why *some* vests also include an NIJ Standard 0115.00 rating and why most don't. Feel free to read up on it.