Feynman's wobbling plate: how to recover from burnout

I decided that it was time for a very radical change. So I deliberately went and looked for a profession I would otherwise never even have considered. A friend of mine invited me to a book binding workshop. The old fashioned kind that is. Before that I have never ever done anything with my hands. I was utterly convinced I didn't have this sort of thing in me at all, but I gave it a try anyway because this was exactly the kind of radical change I was looking for. I fell in love with it immediately and have never looked back again. It turned out to be such a wonderful and fulfilling job. No more stress, no more over-ambition. Instead I get to learn a fascinating profession and I go home every day feeling utterly and completely satisfied.

I do still write code, but strictly in my spare time and strictly those projects I know I will enjoy doing. This ensures that it will always remain as much fun as it was when I first started out.

Unfortunately, the stupid losers at Microsoft and Apple never picked up on this, and eventually the glyph for the apostrophe was standardized as that ugly vertical piece of shit you probably see on your screen right now, which comes from the typewriter days when you would overstrike it with a period in order to make a shitty exclamation point, thus eliminating the need for one key on your cheap-shit typewriter; and the backtick was standardized as being an accent grave with no fucking letter underneath it, which makes a lot of sense when you're printing things out on a fucking dot-matrix printer with backspace, but not on a VT100, let alone a fucking window system.

Well, in the early 2000s, the folks at the X Consortium decided to standardize on making X-Windows apostrophes look like the shitty Microsoft Windows apostrophes, instead of waiting for the douchenozzles at Microsoft to catch up to the ASCII typography we had in the 1970s. So now instead of having shitty quotes only on Microsoft and Macintosh systems, we have shitty quotes everywhere, unless you use non-ASCII characters. (To be fair, all the glyphs looked shitty on X back then, so it's not like we were giving up some kind of Caslonian paradise.) The saving grace is that you actually can use non-ASCII characters now, and they will work everywhere with no problems. They look like this: “Hello, world!” .

Anyway, the reason you still sometimes see the old kind of ASCII quote marks is that not every fucking document on the web gets thrown away in six months, because some of us fucking try to write shit that people will still want to read ten or twenty or a hundred years from now. When you see ``this'', you're looking back in time, to the days when characters were bytes and men were men. I mean, you’re looking back—oh, fuck it.

The basic reason is due to perpendicular axis theorem. If you have a plate, there is some moment of inertia about the axis perpendicular to the plate, and a different moment of inertia about any axis in the plane of the plate. The perpendicular axis theorem says that the moment of inertia about the axis perpendicular to the plate is twice that about the axis in the plane of the plate.

Now, suppose you attach a rod through the plate, but at a bit of an angle, and then you spin the plate around this rod. As you can imagine, it'll take some effort to keep the plate spinning about the rod; it'll be rattling around trying to spin in a different way. Because you're not spinning it about any axis of symmetry, the angular velocity vector is not lined up with the angular momentum vector and so it requires some torque to keep the plate spinning around the axis you want. But if you're just throwing a plate up in the air, you can't exert any torque on it---it's just going on its own. So if the plate is spinning about some funny axis, it has to do so in a special way in order that the angular momentum vector lines up with the angular velocity vector.

So, draw a diagram of this lopsided plate turning around a rod. The angular velocity will have some component perpendicular to the plate and some component parallel to the plate so that the overall angular velocity is parallel to the rod. Let's suppose that the angular momentum vector's component perpendicular to the plate is exactly as long as the component of the angular velocity perpendicular to the plate. Because the moment of inertia in the plane of the plate is half that perpendicular to the plate, the length of the component of angular momentum in the plane of the plate is half the length of the component of angular velocity in the plane of the plate. As you can see, the angular velocity vector is not lined up with the angular momentum vector.

Now we decouple the plate from the rod so that it can also spin about an axis perpendicular to the plate. If we spin the plate about this axis backwards at half the speed it was originally spinning about this axis, the length of the component of angular momentum perpendicular to the plate is now half the length of the same component of the angular velocity. And so the angular momentum vector is now lined up with the rod that we're spinning the overall system around. But because the angular momentum vector and the angular velocity vector are parallel, there's no need to exert any torque on the system to keep it going. So we can remove the rod entirely and the plate will wobble in the air in a ratio of 2:1.