Talk:Coin rotation paradox
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Issues with the Article
[edit]- For one thing, Coin Rotation Paradox is not a hoax.
- It has plenty of sources, both on the web and in books.
- Wolfram Mathworld is most reliable source you can ever get for mathematics related articles.
Novonium (talk) 10:19, 3 August 2012 (UTC)
This article needs sources (RefImprove template)
[edit]The article has no citation in all sections. Only the lead has one.
Siyeou (talk) 14:28, 29 February 2020 (UTC)
Unequal radii
[edit]The formula R/r + 1 is correct. However, the reference – author Y. Nishiyami – doesn't give the formula, much less prove it is true for any R and r. Also, Nishiyama says, “Separating revolution from rotation is helpful for understanding, but doing so does not provide a fundamental solution.” This latter part is not true. For a coin with radius r to make one revolution around a stationary coin with radius R, the center of the moving coin travels a circular path with radius R + r. (R + r)/r = R/r + 1. Likewise, the circumference of the path is 2*pi*(R + r)/(2*pi*r) = R/r + 1 times the circumference of the revolving coin. Rotation is irrelevant. Merjet (talk) 10:33, 20 June 2020 (UTC)
Please, stop this embarrassment!
[edit]Why is English Wikipedia embarrassing itself with this hoax article?! Just take two coins of the same size, draw a line on both and circle one around the standing other. You'll see for yourself that this is ridiculously wrong. And after that, you should burn this article with fire! 141.136.215.208 (talk) 09:01, 1 October 2022 (UTC)
- you should see the new Video from Veritasium Osw719 (talk) 17:17, 1 December 2023 (UTC)
- This isn't even a paradox, it's just geometry. This term has been used in some internet videos or in few books which rather target maths learners than scientific demands. But since it isn't really a paradox and covered by regular geometry, this doesn't need an article for it's own. And even if it does it describes more a phenomen of popular culture than physics. - Flexman (talk) 01:12, 27 December 2023 (UTC)
- Uh, this article is just fine, and plus, multiple people wanna keep this. TheguyinterestedinstuffIG (talk) 22:47, 1 January 2024 (UTC)
- I'm not sure who is arguing for or against the article, but I think it should stay, and support the fact that this is NOT a paradox, not when the person contemplating it uses logic and common sense. This started some years ago when a few students wrote in to the SAT board stating that the question regarding one circle whose radius was 1/3 of a larger circle's radius. The question stated plain and simple, How Many REVOLUTIONS does Circle A make as it travels around the larger circle B? The answer was B, 3 times. And in fact, that is the right answer. Still, the question was thrown out, and this effected the scores of many students who got the answer correct. But fact is, there is.... No paradox. People who support this say that we cannot be concerned with the starting point of the circle where touches the larger circle, even though THAT is in fact the starting point, NOT some marking on the circle, (or coin in this article's case). When the smaller circle starts its path along the larger circle, any letter or upright orientation marking will in fact revolve one more time during the circle's trip around the larger circle. Upright markings on a coin, or the head of a coin, are NOT the starting point of the coin's rotation, and in the case of 2 quarters, the moving coin starts from its bottom, at its six o clock position. When it completes its journey, that coin travels only once along its circumference, and ending once again, at its 6 o clock position... Dijcks | InOut 00:31, 25 July 2025 (UTC)
- The sources clearly consider the topic to be a paradox. That is all that matters to Wikipedia. Johnjbarton (talk) 00:47, 25 July 2025 (UTC)
- I understand, and respect that. A lot of really smart people used to think that "bleeding" patients would heal several illnesses. I don't mean to be combative. I simply pose the idea that when you take JUST the syntax of what is/was being asked when posing these questions, that what happens does logically happen. In the case of the original SAT question, it specifically asked, "How many revolutions...", NOT how many upright turns does a point on the circle (or coin in this case) make.
- I get the idea behind "Herd Immunity". So many people, smart ones too, math whizzes, etc., have supported these arguments, but in every case that I've read, the argument and the points being argued are not the same. I understand that this is an old argument, and those who watch or protect A given article can be adamant, but that doesn't make its statement, correct. Note, I won't drag this out. I just felt the need to make a comment. 172.112.133.7 (talk) 22:19, 27 July 2025 (UTC)
- The sources clearly consider the topic to be a paradox. That is all that matters to Wikipedia. Johnjbarton (talk) 00:47, 25 July 2025 (UTC)
- I'm not sure who is arguing for or against the article, but I think it should stay, and support the fact that this is NOT a paradox, not when the person contemplating it uses logic and common sense. This started some years ago when a few students wrote in to the SAT board stating that the question regarding one circle whose radius was 1/3 of a larger circle's radius. The question stated plain and simple, How Many REVOLUTIONS does Circle A make as it travels around the larger circle B? The answer was B, 3 times. And in fact, that is the right answer. Still, the question was thrown out, and this effected the scores of many students who got the answer correct. But fact is, there is.... No paradox. People who support this say that we cannot be concerned with the starting point of the circle where touches the larger circle, even though THAT is in fact the starting point, NOT some marking on the circle, (or coin in this article's case). When the smaller circle starts its path along the larger circle, any letter or upright orientation marking will in fact revolve one more time during the circle's trip around the larger circle. Upright markings on a coin, or the head of a coin, are NOT the starting point of the coin's rotation, and in the case of 2 quarters, the moving coin starts from its bottom, at its six o clock position. When it completes its journey, that coin travels only once along its circumference, and ending once again, at its 6 o clock position... Dijcks | InOut 00:31, 25 July 2025 (UTC)
- Uh, this article is just fine, and plus, multiple people wanna keep this. TheguyinterestedinstuffIG (talk) 22:47, 1 January 2024 (UTC)
Reverse the GIF of the coin
[edit]Requesting that the GIF depicting the coin made to rotate around another coin be reversed. This is to help viewers compare the coin rotation with the cardioid depiction being done right below it. Understandably this may lead to conflicts with other wiki, so I put this request up for discussion on the TALK page to see if there may be hurdles to consider with this request. Exoscope (talk) 18:16, 9 November 2024 (UTC)
- I have gone ahead and attempted a change that adds this reversed rotation. If there are any concerns, the edition can be reverted by the admin/moderator who keeps track of this page. Exoscope (talk) 18:34, 10 November 2024 (UTC)
Variations
[edit]Ive seen variations of the puzzle where the outside coin is to rotate around the inside coin to arrive at its original point, and believe it or not they had an incorrect answer forgetting the infinitessinal extra distance thst is required for it to go from before the starting point to the starting point. This eas the wording in a famous test which no students apparently got right and even after they still dont count the infinitessinal. They are supposed to be mathematicians striving for correctness snd accuracy. 2405:6E00:2824:6DE2:466:21C6:2933:6AD5 (talk) 21:27, 19 February 2025 (UTC)