Stupid Questions - September 2017

No, the dumbbell-on-a-table is not using any energy to keep from falling down. What takes energy, in general, is not exerting a force but moving things against an opposing force. Getting the dumbbell up into the air takes energy; letting it fall again will release some energy; but that's a one-off, and there isn't any ongoing energy cost to keeping it in the same place.

(Why does the stuff on the surface of the earth not all fall inward and the earth collapse into a black hole? Because as well as the inward force those things experience due to gravity, there are also outward forces, mostly arising from electrostatic repulsion between the electrons on nearby atoms, and when something is sitting motionless on the ground that's because those forces balance one another. This is also what's happening to the dumbbell on the table.)

So maybe the real question here is not "how can the table hold the dumbbell up without expending energy?", but "how come my arm needs to use energy to hold the dumbbell up?". The answer to that is: while there are structures, like a table, that can hold a dumbbell up without using energy, your arm is not built one of them: because it's made from flexibly-articulated bits, and it's only able to achieve the same effect the table can by less efficient means. (But in exchange for that it gets the ability to do things the table can't, like moving the dumbbell around.)

This is a good question. The answer is that it shouldn't take any energy to hold something in place, but your arms are very inefficient. When you keep one of your muscles contracted the individual cells in that muscle are all contracting and relaxing repeatedly. This burns energy. So for a human holding a dumbbell takes energy. But this is just an unfortunate consequence of the way muscles work. If the human body had some way to "lock" the skeleton into place then you would be able to hold a dumbbell for as long as you wanted.

The typical distance between your eyes and the display is closer for a smartphone than for a monitor. If you had both and they had the same resolution the smartphone-pixel would usually take up more of your field of view than the monitor-pixel. The closer the display is to your eyes, the more pixels you'd like it to have. Think about VR headsets as an extreme case: their displays have resolutions like 2160x1200 and people complain that they can see every pixel.

And relating to that, adding more pixels has diminishing returns. Personally for instance I don't care about adding more pixels to current-gen monitors (while keeping the size constant; larger screens need more pixels). Some people would certainly be able to make use of it, but I would hardly benefit. Improvements in color would be very nice though and it's nice to see things start moving into that direction.

My understanding is that there is a limit of what resolution the human eye can resolve.

https://en.wikipedia.org/wiki/Retina_Display

https://www.macworld.co.uk/feature/apple/what-retina-hd-display-are-they-worth-money-apple-3466732/

When Steve Jobs launched the iPhone 4, and with it the first Retina display, he described it as having a screen with so many pixels packed closely together that they were imperceptible to the human eye at a distance of twelve inches. He went to great lengths to explain that, because the iPhone 4’s screen packed in 300 pixels per inch, most people wouldn’t see them at all when the phone was a foot from their eyes.

They are. For instance, here are some you can buy from Amazon. Maybe the question is why they aren't trying very hard to sell us higher-resolution monitors, and I don't know the answer to that. At no time have I understood why users and vendors of computer displays seem so uninterested in their resolution.

But I think part of the story is that if, at roughly fixed physical size, you increase the resolution a lot then either everything becomes very small or you need some sort of fancy resolution-dependent scaling, and the first is bad for users and the second requires either extra work from all software creators or some sort of cleverness in the operating system that delivers nice-looking results even on displays whose resolution is very different from what applications are implicitly expecting.

Those are both things that are just starting to happen recently in the world of Actual Computers. It was able to happen earlier in the world of mobile devices because the OS vendors have more power and individual application authors have less freedom there, and because the whole industry got started later when it was easier to see that display resolutions might improve a lot.

I don't think there is much material records you're supposed to have besides the administrative and medical history polymathwannabe mentioned.

However, as mental record I would add are the memories of the places you've lived in, and significant experiences you've had. You can make some up, but you're supposed to have a story to tell if someone asks small talk questions, unless you're prepared to signal "I don't want to talk about my childhood".

At the barest minimum, your birth certificate (and associated papers that prove your relatedness to people you hope to inherit from), your high school diploma (unless you already have a university degree AND don't intend to pursue another one), and any vitally important medical records.