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How fast does light travel in 1 ft? 
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#1
Aug707, 11:26 PM

P: 2

Hello everyone,
I was wondering if anyone could help solve my problem... ...How much time in seconds (or milleseconds) would light travel in 1ft? (assuming that it was traveling in a vacuum.) I spent 2 and a half hours yesterday trying to solve this problem, but without much luck. I remember back in school, I would know how to do this kind of stuff, but now...well, you know. If anyone knows the answer to this problem (and if possible, a formula), I would much apreciate it. 


#2
Aug707, 11:31 PM

P: 2,050

speed = distance / time. Use google calculator. Welcome to PF.



#3
Aug707, 11:55 PM

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How much time to cover 300,000,000 meters (that's about 1,000,000,000 ft)? So, how much time to cover 1 ft?



#4
Aug807, 12:12 AM

P: 2

How fast does light travel in 1 ft?
Wow, I don't believe how I could forget something so simple. Thanks anyways for reminding me. 


#6
Aug807, 08:14 AM

P: 2,046




#7
Aug807, 09:01 AM

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Light travels at 1 foot / attofortnight, everyone knows that.



#8
Aug807, 03:50 PM

P: 1,345




#9
Aug807, 04:58 PM

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No, a real nerd uses c = 1.8 terafurlongs per fortnight



#10
Aug807, 07:03 PM

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#11
Aug807, 11:21 PM

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#12
Aug807, 11:24 PM

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That would be a good homework question, what is planck's constant in the furlong/firkin/fortnight system.



#13
Aug807, 11:34 PM

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#14
Aug907, 12:29 AM

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h is in Jouleseconds or kg*(m/s)^2*s = kg*m^2/s Although http://en.wikipedia.org/wiki/FFF_System says that firkin is a mass, according to http://en.wikipedia.org/wiki/Firkin and google, firkin is a volume: http://www.google.com/search?q=firkin+in+m%5E3 . However, since it is used with water (whose density is about 1000 kg/m^3), we have an expression for the mass in kg of a firkin of water http://www.google.com/search?q=kg+in...+kg%2Fm%5E3%29 So, since google has a problem with numerical constants in the unit conversion, http://www.google.com/search?q=h%2F1...E2%2Ffortnight h / 1 000 = 4.8405995 × 1034 (firkin * (kg / (m^3)) * (furlong^2)) / fortnight or h = 4.8405995 × 10^(34) (firkin of water) * (furlong^2) / fortnight (FYI: http://www.google.com/search?q=c+in+...+per+fortnight yields the speed of light = 1.8026175 × 10^12 furlongs per fortnight) 


#15
Aug907, 09:21 AM

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Well done, although a traditionalist would say that mass should be a firkin of ale not water!
Some interesting units I hadn't heard of here http://en.wikipedia.org/wiki/List_of...of_measurement 


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