Fermi Questions Marathon

[hmcginny]

oh and my question is: How many acres in a square lightyear?

[harryk]

Schrodingerscat: I think you're bus size estimates are a little high, I got e6

So a lightyear is about 10^16m and there is 1600m in a mile so
e16/-e3 = e13
And square lightyear
e13*e13 =e26
And theres 640 acres in a sq mile
So e26*+e2 =+e26
So my answer is e27, I think

Q: How many years would it take someone to count to a googol?

[hmcginny]

its E28 for acres in a square lightyear, you were good up to the conversion to acres, and then you should have had E28 not E27 E26*+E2 = E28

so a googol is 1E100, so lets say you're counting in your head, so ignore breathing time and eating time. lets say you can count 20 hours a day and sleep the other 4 just so you have enough energy to survive. and the numbers get progressively longer but lets say on average every number takes a minute to think (when it has 50 digits and you have to think about counting without getting lost and the fact that you are continually losing your mind). so you can do E3 every day, so you need E97 days which is E94 years...

How many minutes did people in the United States spend talking on their cell phones in 2010 (just so its possible to google the answer)?

[nejanimb]

2 minutes for 2 days for 8 people.

12.

If all of the Christmas gifts bought in the United States since the year 2000 had been bought using the coin that bears Monticello on one side, how many femtograms of that coin would have been spent?

(good goodness I love this event. I'm so excited to be a supervisor for this.)

[JohnHa]

2 minutes for 2 days for 8 people.

12.

If all of the Christmas gifts bought in the United States since the year 2000 had been bought using the coin that bears Monticello on one side, how many femtograms of that coin would have been spent?

(good goodness I love this event. I'm so excited to be a supervisor for this.)

Population of US: 3E8 times
Presents per person: 7? times
Price of a present: $100 times
nickels in a dollar: 20 times
grams in a nickel: 5 times
femtograms in a gram: 1E15

= 2.1E28 femtograms 13. How much iron is contained in all the red blood cells of an average human?

[Angstrom]

A human breathes about once for every three heartbeats, and every breath most likely is a third of a liter - so each heartbeat (that is, what it takes to refill all the blood in the human body with oxygen) is 100 mL of oxygen. 100 mL / (22.4 L/mol) = 4/1000 moles. Fe2O3 is probably the balance of oxidation, but refilling probably doesn't drain all the iron - so let's assume there is twice as many iron atoms as are refilled as oxygen, so 1/100 moles of iron, times 50 g/mol = 0.5 g.

That seems oddly high, but I don't know how to measure so I'll go with it.

How much energy is lost to sound (does NOT count heat) in a plane flight from New York to LA?

[harryk]

Well partially since I don't know how to solve the above, and also because I have a question I really want to post... I'm going to skip it

If you were to stack all the iPods(all models) sold since it's introduction, how many times taller would the stack be than the tallest building in the world?
And by stacking I mean face-to-back

[quizbowl]

Well partially since I don't know how to solve the above, and also because I have a question I really want to post... I'm going to skip it

If you were to stack all the iPods(all models) sold since it's introduction, how many times taller would the stack be than the tallest building in the world?
And by stacking I mean face-to-back

Well I remember reading that of all the iPods sold, theres enough to give one to every american.
So thats around 3E8 iPods
I'd say an ipod is about 1E-2 meters thick, so thats 3E8*1E-2= 3E6meters tall
The tallest building is the Burj Dubal - I think it was around 1/2 a mile high, so thats around 8E2 meters
3E6/8E2 = 3.8E3 times taller, so the answer is 3.

If molten gold was poured to completely fill a ten gallon hat, what would its weight be, in Newtons?

[hmcginny]

So gold has a density around 20 g/cm^3, and a gallon is around 4 liters. so 10 gallons is ~40 liters or 4E4 ml or cm^3, and thus 8E5 grams. But since you asked for newtons, there are 9.8 newtons in a kg, and 8E5 grams is 8E2 kg or ~7.8E3 newtons, so 4 is my answer.

How many baseballs would it take to cover every baseball park in the world (no stacking)?

[quizbowl]

So gold has a density around 20 g/cm^3, and a gallon is around 4 liters. so 10 gallons is ~40 liters or 4E4 ml or cm^3, and thus 8E5 grams. But since you asked for newtons, there are 9.8 newtons in a kg, and 8E5 grams is 8E2 kg or ~7.8E3 newtons, so 4 is my answer.

Well, mine was a trick question - a 10 gallon hat only holds about 4 liters! So you'd probably be off by 1 order of magnitude, but good job.