system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: When we get issued plates for our IOTV vests in the army, we get told not to drop the plates or they might shatter. How can these plates that are rated for a 7.62x54mm bullet stop said bullet if they can't even hold up when they get dropped?
gpt
It's not about being so hard as to stop the bullet. It's about reducing the amount of energy the bullet is carrying. Transferring that energy into the ceramic and distributing it throughout lessens the energy. As stated above cars are made to crumple at the hood forward. That way the energy of the impact is spread into the front of the vehicle instead of in your body. It's like a stuntman coming off a high jump. If he lands directly on his feet he will snap his legs. If he rolls he distributes the energy and doesn't get injured.