Cool math clock « Next Oldest | Next Newest »

 ▼ Bruce Bergman Senior Member Posts: 553 Threads: 57 Joined: Sep 2006 04-04-2013, 11:50 AM All you math geeks will love this! :-) ▼ hugh steers Senior Member Posts: 536 Threads: 56 Joined: Jul 2005 04-04-2013, 12:47 PM some of the values aren't strictly accurate. :-) ▼ Dave Shaffer (Arizona) Posting Freak Posts: 776 Threads: 25 Joined: Jun 2007 04-04-2013, 01:17 PM And 4 O'Clock doesn't work very well unless you use ln (rather than log - which I usually take to be base 10) ▼ Harald Senior Member Posts: 455 Threads: 39 Joined: Jan 2011 04-04-2013, 05:51 PM That is the one that I stumbled over as well. Marcel Samek Member Posts: 189 Threads: 39 Joined: Nov 2011 04-04-2013, 05:21 PM The numbers might be perfectly accurate. You are just assuming that they are spaced at even 5 minute intervals around the dial when they might not be. ▼ Jeroen Van Nieuwenhove Member Posts: 88 Threads: 5 Joined: Mar 2011 04-04-2013, 06:52 PM In that last case, aren't you assuming a one hand clock? Dan Grelinger Senior Member Posts: 351 Threads: 49 Joined: Mar 2008 04-04-2013, 03:48 PM I will admit to not understanding '10'. ▼ Neil Hamilton (Ottawa) Senior Member Posts: 255 Threads: 22 Joined: May 2011 04-04-2013, 03:59 PM I think that should be round(g) -- as in acceleration due to gravity (on earth). ▼ Dave Shaffer (Arizona) Posting Freak Posts: 776 Threads: 25 Joined: Jun 2007 04-04-2013, 04:14 PM The value of g (acceleration of gravity at the surface of the Earth) is about 9.80 m/sec^2 ▼ Walter B Posting Freak Posts: 4,587 Threads: 105 Joined: Jul 2005 04-04-2013, 04:38 PM Quote: The value of g (acceleration of gravity at the surface of the Earth) is about 9.80 m/sec^2 The official value is 9.80665 m/(s^2) per definition. d:-) Neil Hamilton (Ottawa) Senior Member Posts: 255 Threads: 22 Joined: May 2011 04-04-2013, 05:02 PM I guess I just assumed that folks would know this was in the units of m/s^2. :-) I might have to be more careful on this forum and spell it out. ▼ Walter B Posting Freak Posts: 4,587 Threads: 105 Joined: Jul 2005 04-05-2013, 12:39 AM Maybe Dan was thinking in Royal British thumbs per s^2? Or Imperial feet per s^2? Or yards per s^2? Who dares to claim he knows ... d;-) ▼ Dan Grelinger Senior Member Posts: 351 Threads: 49 Joined: Mar 2008 04-05-2013, 08:14 AM I learned g as 32ft/s2. That was 35 years ago and it sticks in my brain. ▼ Xavier A. (Brazil) Member Posts: 103 Threads: 11 Joined: Nov 2008 04-07-2013, 02:12 PM MASK (Mètre - Ampère - Seconde - Kilogramme) is what I've learned in high school as a universal standard. Regards. By the way, what is this expression of 7? ▼ Gerson W. Barbosa Posting Freak Posts: 2,761 Threads: 100 Joined: Jul 2005 04-07-2013, 02:43 PM That's an indication of repeating decimal digits. ``` _ 6.9 = 6.99999999999... = 7 ``` Regards, Gerson. ▼ Xavier A. (Brazil) Member Posts: 103 Threads: 11 Joined: Nov 2008 04-08-2013, 08:56 AM Ah, okay, thank you, Gerson. It is a bit confusing for Europeans (French people particularly) since a dot is rather a multiplication sign than a... coma. Therefore I saw 9 as a mean value! Dan Grelinger Senior Member Posts: 351 Threads: 49 Joined: Mar 2008 04-08-2013, 12:31 PM Yes, you likely grew up outside the influence of the U.S. When I was in grade school (40 years ago) there was a failed attempt here to push the metric system into wide use. I remember a gasoline station near my home reset their pumps to dispense gasoline in liters instead of gallons. However, instead of pricing gasoline as the equivalent to the station selling in gallons next door, they priced it much higher, assuming that people would not be smart enough to know the difference. That lasted for about 6 months, but obviously people figured it out, and the station had to revert back to pricing in gallons at a competitive price. If only this station had priced their gasoline CHEAPER than competing stations selling in gallons, perhaps the SI conversion in the U.S. would have been successful. The SI units have been proposed as the 'universal standard', but when a proposal is only adopted by some and not all, it perhaps is not yet truly universal. Not that it shouldn't be. It is just that old habits are hard to break. ▼ Xavier A. (Brazil) Member Posts: 103 Threads: 11 Joined: Nov 2008 04-08-2013, 01:16 PM Good precisions, Dan. If Napoléon hadn't sold Louisiana for peanuts (money unit in the unofficial S.I), perhaps things would have changed another way. But actually... you are right. Mark Hardman Member Posts: 208 Threads: 16 Joined: Jul 2005 04-06-2013, 06:00 AM In general terms: ```1k = 1,000 (a 4 digit number) im = 1,000,000 (a 7 digit number) 1g = 1,000,000,000 (a 10 digit number ``` Just a thought. Mark Hardman ▼ Walter B Posting Freak Posts: 4,587 Threads: 105 Joined: Jul 2005 04-06-2013, 09:05 AM Quote: ```1k = 1,000 (a 4 digit number) im = 1,000,000 (a 7 digit number) 1g = 1,000,000,000 (a 10 digit number ``` No, Sir. 1M = 1.000.000 and 1G = 1.000.000.000. All pre-letters greater than k are upper case. d:-) Edited: 6 Apr 2013, 9:08 a.m. ▼ Mark Hardman Member Posts: 208 Threads: 16 Joined: Jul 2005 04-06-2013, 07:58 PM Wow Walter. Did you forget to take your medications today? ▼ Walter B Posting Freak Posts: 4,587 Threads: 105 Joined: Jul 2005 04-08-2013, 12:26 AM Mark, Quote: Wow Walter. Did you forget to take your medications today? ??? TIA for enlightenment. d:-? P.S. Can't help it, but I've seen such errors only made by US Americans. Dan Grelinger Senior Member Posts: 351 Threads: 49 Joined: Mar 2008 04-08-2013, 12:32 PM So, the symbol at the 10 o'clock position is really 1,000,000,000? ;-) Namir Posting Freak Posts: 2,247 Threads: 200 Joined: Jun 2005 04-04-2013, 05:21 PM Found a similar one (black background) on Amazon for \$21 and ordered it. Thanks for sharing!!! :-) Namir Alexander Oestert Senior Member Posts: 429 Threads: 31 Joined: Jul 2011 04-05-2013, 08:31 AM I don't buy "10" and I don't understand "11". ▼ Andrés C. Rodríguez (Argentina) Posting Freak Posts: 1,193 Threads: 43 Joined: Jul 2005 04-05-2013, 08:57 AM For me, "10" is the rounded value of acceleration of gravity on Earth, i.e. 9.8 m/s^2; "11" is 0B in hexadecimal. Other interpretations may be valid, who knows? For many practical estimations, "10" can be seen as "3 x 3" or "(pi)^2", I use these examples when discussing significant digits issues on my courses. HTH ▼ Alexander Oestert Senior Member Posts: 429 Threads: 31 Joined: Jul 2011 04-07-2013, 03:21 AM Ha! Thanks! I didn't recognize that letter in "0b" as a "b". If "10" is supposed to be "rounded 9.81", why doesn't it say so as it does with the "3"? The clock is a nice idea but has too many flaws for my taste. Jim Horn Member Posts: 151 Threads: 8 Joined: Oct 2009 04-05-2013, 12:45 PM Somebody cast a hex on the "11"... ▼ Siegfried (Austria) Junior Member Posts: 23 Threads: 3 Joined: Jan 2013 04-10-2013, 03:13 AM Would it conflict with the forum rules if the happy owners of the clocks posted links to sellers? I found the following in a German shop but most of the math exceeds my abilities. http://www.getdigital.de/products/Matheuhr/more/pic

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