Cool math clock

[Bruce Bergman]

All you math geeks will love this! :-)

[hugh steers]

some of the values aren't strictly accurate. :-)

[Dave Shaffer (Arizona)]

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]

That is the one that I stumbled over as well.

[Marcel Samek]

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]

In that last case, aren't you assuming a one hand clock?

[Dan Grelinger]

I will admit to not understanding '10'.

[Neil Hamilton (Ottawa)]

I think that should be round(g) -- as in acceleration due to gravity (on earth).

[Dave Shaffer (Arizona)]

The value of g (acceleration of gravity at the surface of the Earth) is about 9.80 m/sec^2

[Walter B]

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)]

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]

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]

I learned g as 32ft/s². That was 35 years ago and it sticks in my brain.

[Xavier A. (Brazil)]

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]

That's an indication of repeating decimal digits.

  _

6.9  = 6.99999999999...  = 7

Regards,

Gerson.

[Xavier A. (Brazil)]

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]

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)]

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]

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]

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]

Wow Walter. Did you forget to take your medications today?

[Walter B]

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]

So, the symbol at the 10 o'clock position is really 1,000,000,000? ;-)

[Namir]

Found a similar one (black background) on Amazon for $21 and ordered it. Thanks for sharing!!!

:-)

Namir

[Alexander Oestert]

I don't buy "10" and I don't understand "11".

[Andrés C. Rodríguez (Argentina)]

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]

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]

Somebody cast a hex on the "11"...

[Siegfried (Austria)]

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