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

KE (Kinetic Energy) = 1/2 * m * v^(2)

Rifle rounds travel much much faster than handgun rounds. This velocity is squared in the KE equation. So, a bullet from a rifle of the same weight might have 4-10 times the energy of the handgun bullet.