Fermi Questions C

[Angstrom]

This event is going to be fun. If any of you are interested in a more precise and less "silly" (by that I only meant the type of problems) form of Fermi - i.e. the original Fermi problem with the atomic bomb, and things like that, you should check out Caltech's Order of Magnitude Physics class - http://www.its.caltech.edu/~oom/ is the link. I don't think it's a good study resource for Fermi as an event, but it's fun to go through, and for me, that's more important.

And by the way, 70! is 10^106. I say this because a couple months ago, I was evaluating factorials and my calculator stopped at 66 or 67 factorial, suggesting that that's where you hit 10^100, so sqrt(67) * 68 * 69 * 70 = 70^3.5 = 343000 * sqrt(70) = 3e6.

[quizbowl]

This event is going to be fun. If any of you are interested in a more precise and less "silly" (by that I only meant the type of problems) form of Fermi - i.e. the original Fermi problem with the atomic bomb, and things like that, you should check out Caltech's Order of Magnitude Physics class - http://www.its.caltech.edu/~oom/ is the link. I don't think it's a good study resource for Fermi as an event, but it's fun to go through, and for me, that's more important.

And by the way, 70! is 10^106. I say this because a couple months ago, I was evaluating factorials and my calculator stopped at 66 or 67 factorial, suggesting that that's where you hit 10^100, so sqrt(67) * 68 * 69 * 70 = 70^3.5 = 343000 * sqrt(70) = 3e6.

Actually, 70! is about 10^100.

[Bogoradwee]

quiz is right. I just checked with the calculator on my computer. I got 1.198e100

[lllazar]

Ok so i'm a bit perplexed right now by the answer key for this test:

Test: http://scioly.org/w/images/e/e2/2008_FermiWayzata.pdf
Key: http://scioly.org/w/images/c/cc/2008_Fe ... ataAns.pdf

Look at questions 2-4. The answers are completely wrong, or I am failing epically at math.

, and thus the answer for 2 should be . Look at 3 and 4 as well, they should be and respectively....

[hmcginny]

so for 2 it's actually saying 10 ^ (10^-10). 10^-10 is 1E-10, so the problem is really asking what is 10 ^(1E-10). 1E-10 is very close to 0 so your answer is 0. You just placed the parentheses incorrectly when you were doing it in your head.

3 is 10^(10^(10^-10)), 10^-10 is 1E-10, 10^(1E-10) is 1 as seen above, so the answer is 1.

4 is 10^(10^(10^(10^-10))), use the stuff from three to get down to 10^(10^1) which is 10^10 so the answer is 10.

I hope that helped. I think your only problem was your idea of where the parentheses would go.

[lllazar]

Thanks

[cngu23]

Are you allowed anything in with you (paper, pencil, calculator)?

Just a writing utility. Nada mas.

So for this event, will all of the problems be solved by multiplying stings of unit conversions? Or may there be a problem such as how many years will it take for the population to reach 1 trillion? (growth rate formula + conversions)
Just want to make sure because some of the questions asked in the "fermi questions marathon" do not only involve multiplication.

[Schrodingerscat]

I would personally be prepared for more than simple multiplication and conversion problems, as the rules never specifically limit it to them.

[cngu23]

I would personally be prepared for more than simple multiplication and conversion problems, as the rules never specifically limit it to them.

"In science, particularly in physics or engineering education, a Fermi problem, Fermi question, or Fermi estimate is an estimation problem designed to teach dimensional analysis, approximation, and the importance of clearly identifying one's assumptions."
-http://en.wikipedia.org/wiki/Fermi_problem

So I guess it could be more complicated than just unit conversions and multiplication. But so far, all of the sample problems haven't been more complex than that.

[quizbowl]

I found it hilarious that the Training Powerpoint is basically the wiki (exactly copied word for word at points) in powerpoint format

[rfscoach]

I found it hilarious that the Training Powerpoint is basically the wiki (exactly copied word for word at points) in powerpoint format

Fermi has been around for years. Perhaps the wiki info was taken from an earlier powerpoint, which event supervisors save and recycle when the event rotates back in....

[49ers]

so let me make sure i understand this event:
random questions with numbers and then you have to answer with a power of 10
nothing but a pencil/pen

and one question: How do you round these numbers?

[hmcginny]

Any number greater that is 5 or greater is rounded up to the next power of 10, anything lower than 5 is rounded down.

Examples:
5.001 *10^3 is 4
5 * 10^3 is 4
4.99 * 10^3 is 3

[Bogoradwee]

Is that on the rules (I haven't been able to see an official copy of the rules yet)? I was under the impression that you don't round it, and whatever the exponent is is just the answer. So 5E3 would be 3, and 5.1E3 woul still be 3. However, if you have 9.9999E3, depending on how you came to your answer, you would probably want to round up, or keep it at 3 if you know your answer is probably a little higher than the actual answer...

[49ers]

Is that on the rules (I haven't been able to see an official copy of the rules yet)? I was under the impression that you don't round it, and whatever the exponent is is just the answer. So 5E3 would be 3, and 5.1E3 woul still be 3. However, if you have 9.9999E3, depending on how you came to your answer, you would probably want to round up, or keep it at 3 if you know your answer is probably a little higher than the actual answer...

I am certain it is in the rules. I will quote: "If C is 5 or greater (to 9.99...), round C up to 10."