Why can’t a bullet proof vest protect you from a knife stab?

Question

I mean, it’s designed to stop a bullet which delivers much more force than a human being can ever produce during stabbing

In: 784

Answer 1

Kevlar is really good at resisting stretching. Like 5-10 times stronger than steel kind of good. But it’s made of tiny fibers and those fibers can be cut (although they’re tough, they’re not so tough that a steel edge can’t cut them).

Compare it to a fishing net. It’s a really strong fishing net, strong enough to catch bullets. But a knife is a knife, so it cuts the fibers and goes through.