Cool math clock - Printable Version +- HP Forums (https://archived.hpcalc.org/museumforum) +-- Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum-1.html) +--- Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum-2.html) +--- Thread: Cool math clock (/thread-241595.html) Cool math clock - Bruce Bergman - 04-04-2013 All you math geeks will love this! :-) Re: Cool math clock - hugh steers - 04-04-2013 some of the values aren't strictly accurate. :-) Re: Cool math clock - Dave Shaffer (Arizona) - 04-04-2013 And 4 O'Clock doesn't work very well unless you use ln (rather than log - which I usually take to be base 10) Re: Cool math clock - Dan Grelinger - 04-04-2013 I will admit to not understanding '10'. Re: Cool math clock - Neil Hamilton (Ottawa) - 04-04-2013 I think that should be round(g) -- as in acceleration due to gravity (on earth). Re: Cool math clock - Dave Shaffer (Arizona) - 04-04-2013 The value of g (acceleration of gravity at the surface of the Earth) is about 9.80 m/sec^2 Re: Cool math clock - Walter B - 04-04-2013 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:-) Re: Cool math clock - Neil Hamilton (Ottawa) - 04-04-2013 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. Re: Cool math clock - Namir - 04-04-2013 Found a similar one (black background) on Amazon for \$21 and ordered it. Thanks for sharing!!! :-) Namir Re: Cool math clock - Marcel Samek - 04-04-2013 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. Re: Cool math clock - Harald - 04-04-2013 That is the one that I stumbled over as well. Re: Cool math clock - Jeroen Van Nieuwenhove - 04-04-2013 In that last case, aren't you assuming a one hand clock? Re: Cool math clock - Walter B - 04-05-2013 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;-) Re: Cool math clock - Dan Grelinger - 04-05-2013 I learned g as 32ft/s2. That was 35 years ago and it sticks in my brain. Re: Cool math clock - Alexander Oestert - 04-05-2013 I don't buy "10" and I don't understand "11". Re: Cool math clock - Andrés C. Rodríguez (Argentina) - 04-05-2013 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 Re: Cool math clock - Jim Horn - 04-05-2013 Somebody cast a hex on the "11"... Re: Cool math clock - Mark Hardman - 04-06-2013 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 Re: Cool math clock - Walter B - 04-06-2013 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. Re: Cool math clock - Mark Hardman - 04-06-2013 Wow Walter. Did you forget to take your medications today? Re: Cool math clock - Alexander Oestert - 04-07-2013 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. Re: Cool math clock - Xavier A. (Brazil) - 04-07-2013 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? Re: Cool math clock - Gerson W. Barbosa - 04-07-2013 That's an indication of repeating decimal digits. ``` _ 6.9 = 6.99999999999... = 7 ``` Regards, Gerson. Re: Cool math clock - Walter B - 04-08-2013 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. Re: Cool math clock - Xavier A. (Brazil) - 04-08-2013 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! Re: Cool math clock - Dan Grelinger - 04-08-2013 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. Re: Cool math clock - Dan Grelinger - 04-08-2013 So, the symbol at the 10 o'clock position is really 1,000,000,000? ;-) Re: Cool math clock - Xavier A. (Brazil) - 04-08-2013 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. Re: Cool math clock - Siegfried (Austria) - 04-10-2013 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