Max

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Max last won the day on January 15

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    Max Keller

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  1. Max

    Tether a Spinning Ball

    I saw just for a second or so the Windows hourglass, and then everything was the same as before, filename etc. No message or other symbols appeared. But since today it suddenly works! As far as I know, I didn't change anything since the last time it wouldn't work, so it's a great mystery. The only thing I can think of is that one of those attempts to remedy the problem I mentioned in my previous post, did in fact have the desired effect, but only after restarting the computer, although there was no message to that effect. But I'm glad that I now can explore the program on my big screen. It looks great!
  2. Max

    Tether a Spinning Ball

    As I already wrote, the program runs fine on my laptop (Windows 10 home). I copied that file to my PC (Windows 10 Pro), but there it just doesn't do anything, not even saying "Unknown Publisher". I tried changing protection settings, run as Administrator, compatibility mode, all to no avail.
  3. Max

    Tether a Spinning Ball

    I've no such things that could be used, but Amazon is your friend: I ordered a set of laces, flat and 160 cm long and a set of 10 cm styropor balls.
  4. Max

    Tether a Spinning Ball

    I copied the file from my laptop to my PC, but there it still doesn't do anything...
  5. Max

    Tether a Spinning Ball

    Nothing happened, at least I didn't see anything happen, I downloaded it again, but with the samer result. This was on my PC with Windows 10 pro. I just tried it on my laptop with Windows home, and now it worked! Strange. I'll try it later again on the other computer and compare the files.
  6. Max

    Tether a Spinning Ball

    This is a fascinating subject, quite counterintuitive. I downloaded the program, but that doesn't do anything on my computer (at least I hope it doesn't do some hidden damage...). I'd like to play with such a system, but I don't have flat shoelaces or something similar that can be used to observe the twists clearly. Parhaps I should order aome of them on Amazon... I'd like some hands on experience. Rotating twice to get the original configuration back, that seems to be tied(!) to the SU(2) group and its difference from the SO(3) group. I should lookup those things again... Let me guess: if 1,2,3 works, so do 2,3,1 and 3,1,2, or just the other three?
  7. Max

    Aristotle's wheel paradox

    That is of course the fallacy. The interval [0,2] contains infinitely many points, and infinity is not a natural number, therefore the notion of density doesn't work, as the density is also infinite, and 2 * ∞ = ∞. Cantor, cardinality, continuum and all that. It isn't surprising that people like Aristotle and Galileo didn't understand such things well. Therefore those helpless attempts to consider circles "jumping" or "waiting" to make up for differences in traveled distance in Aristotle's paradox.
  8. Max

    Aristotle's wheel paradox

    I know, this was in fact just a first attempt, with the idea that I later could improve on it, I had also doubts about some of my assumptions, but as the result was fairly close to what one might expect (perhaps I was lucky?) and enough to falsify Merlin's argument, I decided to write it up. I used the frame that you posted earlier.
  9. Max

    Aristotle's wheel paradox

    As I wrote, it was an approximation, not an exact calculation. I neglected the vertical shrink factor, as the relevant vertical distance differences are much smaller than the horizontal differences. I used the width of the wheel, because the height could not accurately be measured, When I try to make an estimate for the height, I get 489, i.e. 1% less than the widthI measured. I could of course make more estimates by drawing lines with various angles through the center of the wheel, but as this "rough calculation" as I called it gave already a result that is quite close to the value expected when the wheel rolls without slipping, this was for me enough to falsify Mernlin's claim that the video didn't show a non-slipping wheel. But of course you may improve the results by using more exact calculations.
  10. Max

    Aristotle's wheel paradox

    I’ve tried to use a simple approximation for testing the video picture. First I tried to measure distances on the screen, but then I realized it would be easier and more accurate to copy the image to a graphics program and use the pixel coordinates in that program. First I calculated a “shrink factor” f by measuring the height of the wooden blocks: 123 left, 94 right (pixel coordinates in my copy of the image): f = 94/123 = 0.764 The white dots at the left give the start position and the corresponding dots at the right the end position. To measure the distance the wheel travels, I drew “vertical” lines through the dots at the left and at the right, and a line through the center of the wheel “parallel” to the lines of the system (that is, using the same shrink factor for perspective). Then I measured the distance between the intersections of this line with those “vertical” lines = 1819 – 470 = 1349. This is the “shortened” distance, DS. Next I measured the diameter of the wheel, right – left = 969 – 475 = 494. Calculating the “real” distance of the wheel, rolling without slipping during one revolution: π * DR = 1552. (DR – DS) / DS = 0.15. That is where Merlin’s “20%” comes from. He probably measured the distance at the bottom, which is extra shortened by the “up-down” perspective, increasing the deviation further. To calculate the “shortened” distance from the “real” distance we should integrate the variable shrink factor over the line from start to finish. But in the linear approximation this boils down to the average value (1 + f) / 2 = 0.882. Then we get 0.882 * 1552 = 1369. Compare with the direct measurement 1349 gives a difference of 20, a deviation of 1.4%. Not bad for such a rough calculation, I’d say.
  11. Max

    Aristotle's wheel paradox

    Strange, "choose files" works fine for me (apart from upload limits...), I just put the cursor on the desired file, hit <enter> and the picture is uploaded (apart from...) Total Commander is one of those Norton Commander type file manipulation programs for Windows, I use it because I then can avoid that horrible dragging... In general such a limit is the amount of data you can upload in a certain period (1 day, 1 week, etc.), at the end of that period the limit is reset. At the moment my limit is only 0.02 MB. You can find it at the bottom of your edit window, under "choose files": "total size 0.02 MB" in my case.
  12. Max

    Aristotle's wheel paradox

    I don't know Irfanview, but although such programs can read and write GIF files, the image in the working memory is expanded to enable viewing and editing it, so I can imagine that a simple copy/paste generates uncompressed files. BTW, personally I don't like dragging and dropping, I prefer the "choose files" option, just as I always use the Total Commander instead of the Explorer, but of course your mileage may vary.
  13. Max

    Where are you?

    Ah, finally I got the 3rd graph belonging to this post uplodaded: I just realized that I should have saved those graphs in GIF format, which in this case is much more efficient. I still had to cut a part with explanations of the symbols to get it small enough, but these are the same as on the previous graph. so that's no great loss. But I'd still like to now how long I must wait before my upload limit is reset again. Obviously more than a day; a week, a month, a year, forever...?
  14. Max

    Where are you?

    Hm, uploading the third graph doesn't work... In the second one some lines have disappeared when I made it smaller to allow it to upload. Do I have an upload limit for today or so?
  15. Max

    Where are you?

    Fig. 1