why can’t kevlar stop rifle bullets even though it’s strong than steel on an equal weight basis?

Question

Ar500 steel plate can stop rifle bullets. In my brain I’m thinking like “well if kevlar is stronger than steel, then slab of kevlar of the same size of an ar500 plate should stop rifle bullets too”. Clearly it doesn’t and I don’t understand why

In: Engineering

Answer 1

Big difference? Speed. A typical rifle round leaves the firearm at 1600-2000MPH. A typical handgun round is doing about 800MPH.

If I accidentally toss a baseball at a window, there’s a good chance it won’t even break. A MLB pitcher takes the same baseball and flings it? it’s going through that window and maybe the sheetrock across the room!