/sci/ - Science & Math

>>11368657
>Is crack-settling the mechanism of friction, or is it Van-Der-Waals sticking?
All of the above.
>Is the time scale for crack settling really large compared to the sticking and unsticking time for contacts?
The ratio of the length scale of grain boundaries and microscopic cracks to whatever is happening on the atomic level is ~10^3-10^4, so I would crudely estimate that yes, the time scale for crack settling is large compared to intermolecular forces.

I was sitting in a math class. My professor said "The Dirac Delta is not a function". Immediately, I stood up and asked why. He said "Distributions aren't functions. Besides: what would be the co-domain of that so-called delta function?". Typical low IQ statement. I started reciting mechanical engineering equations from my memory. My analysis professor stuttered in disbelief, dropped his books and ran out of the room. Everyone in the class stood up and cheered for me. It felt great knowing value in being able to determine the impulse response of a linear system. Suddenly, the math department chair walked in and asked for me. Everyone else sat down and I left and went to his office. He asked me why I made the analysis prof cry. I replied "Sir, you math nerds need to get your head out of dumb books. Theorems and definitions are gay. Prototypes and empirical justification is cool". He thought and then brought out an IQ test. I took it, and within 15 minutes, I had finished. My score was 1.699973E+2. While I was not surprised at all by this number, my principal was absolutely amazed and was at a loss for words. I went back to class and my crush walked up to me kissed me. The day resumed as normal until I went home. I had a letter in the mail. It was from Cal Tech.