re: #74 LudwigVanQuixote

OK guys, I am a little shocked that I need to write this.

Energy is conserved. If you fire a bullet up into the air, and forget about air resistance, it comes down at the exact same speed that it started with.

However, velocity is a vector and speed is not velocity.

What matters to this question, is how much of the velocity was pointed at the target at time of impact. So say some fool fires a bullet straight up - or nearly straight up. The velocity is almost all in the vertical direction. So, if you are standing under a bullet when it comes down it is exactly like you had lain on your tummy and someone shot horizontally at your head. On the other hand, if you are vertical and the bullet is not coming down directly on top of you, it has very little horizontal velocity or momentum. It will graze.

What I’ve bolded makes a big difference once you shift from the theoretical into the reality.