Hacker News Reader

Yes, the energy required to make permanent deformations in a material is unrelated to it's kinetic energy.

I'd rather get hit in the head by a ten pound blob of clay than a five pound iron ball. (Preferably neither, though.)

I think I'd pick the iron ball? I'd have to feel the clay first.

Would you rather be hit by a moving concrete wall or a moving concrete wall at the same speed but with 5 layers of cardboard boxes taped to it.