Saturday, April 22, 2006

4/22/06 Exarads

I continue to play that "Da Vinci Code" game. I complete the puzzle today and got a question: To the nearest whole number what is 1 divided by the permeability of free space, the divided by the permittivity of free space, in exarads? As you know by now, I'm a bit of a nerd and actually tried to figure out the answer. I got as far as "c ^2" (The speed of light squared). (Note: I could be wrong. But I seriously doubt that anyone who reads this is going to try and prove otherwise). Then, I searched on the unit "exarad". Nothing. I got one page that showed "exarad" as a unit with no explanation. I need some help here. What the hell is an exarad?

On the suggestion of my neighbor, James, I picked up the movie Waking Life at the library. I finally watched it last night. I will pass on the high recommendation to you. It's a very trippy, yet though provoking independent film.

5 comments:

Mister Abrams said...

Exa is a prefix...meaing 10^18 (quintillion)

http://www.alcyone.com/max/reference/physics/prefixes.html

Rad is short for radian (which you know what that is...)

Hope that helps...

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Mister Abrams said...

Exa is a prefix...meaing 10^18 (quintillion)

http://www.alcyone.com/max/reference/physics/prefixes.html

Rad is short for radian (which you know what that is...)

Hope that helps...

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It's Your Source for Science!

Mister Abrams said...

Exa is a prefix meaning a quintillion. (10^18)

http://en.wikipedia.org/wiki/Exa

Rad is short for radians which you know what they are.

I have completed all of the puzzles and not gotten that type of question....

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www.nachosrule.com said...

Now I'm REALLY confused. A radian is a dimensionless unit of measure. So now I'm supposed to convert velocity (meters/second or miles/hour or whatever) into something without units?

http://en.wikipedia.org/wiki/Radian

The good news is - I tried the puzzle again and, once completed, gave me a new, easier question.

The bad news - Despite Bob's excellent explanation, I remain as confused as ever. (Which probably indicates that my original answer of c^2 is wrong).

Joanna said...

Nope, you're right! Bob is a tad off. The answer works out to be c^2 (c = light speed = 299,792,458 m/s, obviously). But they want it in exarads! Eep! Rads don't refer to radians here, but radiation (http://en.wikipedia.org/wiki/Rad_%28unit%29), which is expressed in J/kg (joules per kilogram), which can be converted to m^2/s^2 (http://www.vsg.cape.com/~pbaum/si.htm). So by rounding up to the nearest whole number you get an answer of 9. This game was made for geeks like us! :P