Friction, Drag, and Sound
The unsung heroes of the average world
Let's be honest, most people don't really think about friction till it lets them down, and they end up sprawled on the ground in a heap. One of my oldest memories as a child is watching recorded reruns of the magic school bus, and I still remember the episode where they tried to play baseball with no friction. Everyone sliding around and bumping into each other, unable to turn or control themselves without grabbing something and pushing off of it (though if there really was no friction at all, not even that would be possible.)
So picking up the super hero physics book, I grabbed the chapter on the flash.
So the book addresses that yes, the flash could jump over a building going at the speeds that he runs at. But would it be possible to run up the side? Well it all depends on friction. Every time someone takes a step, it causes a massive catastrophic event on a molecular scale. The surfaces of atoms collide, breaking and creating bonds to create what we know as friction. So can the flash run up the side of a building? Technically, yes, though it's more like bouncing. Though I predict something like this as a result. If he runs at a angle like that, gravity is going to pull down his upper half and he's going to go back flipping down the side of the building. Also, that radical change in direction from going vertical and then to horizontal. I think all super heroes are just indestructible because nobody should be able to do this. According to my roommate, Flash has "The Speed Force" which would allow him to ignore physics. But that doesn't make everything around him immune to physics! I think the glass would shatter from the impact of a person moving that fast.
This, on the other hand, is totally possible. He's moving so fast that the water can't move out of the way fast enough to allow him to sink. It's like water skis, move fast enough and you glide along the water. Same principle. In a way, the flash is bullet proof, but only when moving in the opposite direction. A bullet can't hit you if you outrun it.