And that's when I met you
YEAH!
It's been an interesting week. Back at uni, waking up at a respectable time. My timetable is actually quite good though. No really long days. And so far my classes have been interesting so that'll keep me awake too. There has been an area of my thoughts in the past few weeks which I have endeavoured to keep out of my blog, appart from the subtle things between the lines as per usual. But I just want to say that I have been feeling quite happy with myself and actually smiling a whole lot more than usual. Hopefully one day I'll elaborate on this, though I'm sure most of you know by now since word travels faster around here than an ethiopean with a cheeseburger. :P
Perhaps in a fortnight I'll be able to say something here. Who knows. Here's to hoping.
I've got interesting homework for theoretical (physics) in which we have to estimate the answer to strange questions without actually looking things up. These questions are known as Fermi Questions.
Some examples include:
What frequency of radiation is used in TV transmission?
How long would it take a solar sail powered spaceship to travel to mars?
How long does it take a deceased human body to reach room temperature?
How large a moon can you jump off of?
According to my calculations the largest moon which you could jump off of has a radius of 4.5 kilometers. Any larger than that and the gravity would hold you on, even though very loosely. Perhaps a 5km radius you could jump 3km off of the surface but would eventually sail back to it instead of floating off into space. This is of course based on several assumptions. That the highest I can jump on earth is moving my centre of mass up by about 60cm. That a typical moon is made of similar rocks to what we have here which have a density of about 3 times that of water so 3000kg per cubic metre.
Hmm I'm going to look up to see if anybody real has done this calculation before to see how realistic my guess was? :)
Ok, seems like they havent. Or haven't put it anywhere easy to find from google.
I'm really curious how to estimate the TV one. I gather it's possible based on how much information needs to be transmitted to a tv for the picture to be clear but i'm not entirely sure how much, and how much can be sent by different frequency of radio waves.
It's been an interesting week. Back at uni, waking up at a respectable time. My timetable is actually quite good though. No really long days. And so far my classes have been interesting so that'll keep me awake too. There has been an area of my thoughts in the past few weeks which I have endeavoured to keep out of my blog, appart from the subtle things between the lines as per usual. But I just want to say that I have been feeling quite happy with myself and actually smiling a whole lot more than usual. Hopefully one day I'll elaborate on this, though I'm sure most of you know by now since word travels faster around here than an ethiopean with a cheeseburger. :P
Perhaps in a fortnight I'll be able to say something here. Who knows. Here's to hoping.
I've got interesting homework for theoretical (physics) in which we have to estimate the answer to strange questions without actually looking things up. These questions are known as Fermi Questions.
Some examples include:
What frequency of radiation is used in TV transmission?
How long would it take a solar sail powered spaceship to travel to mars?
How long does it take a deceased human body to reach room temperature?
How large a moon can you jump off of?
According to my calculations the largest moon which you could jump off of has a radius of 4.5 kilometers. Any larger than that and the gravity would hold you on, even though very loosely. Perhaps a 5km radius you could jump 3km off of the surface but would eventually sail back to it instead of floating off into space. This is of course based on several assumptions. That the highest I can jump on earth is moving my centre of mass up by about 60cm. That a typical moon is made of similar rocks to what we have here which have a density of about 3 times that of water so 3000kg per cubic metre.
Hmm I'm going to look up to see if anybody real has done this calculation before to see how realistic my guess was? :)
Ok, seems like they havent. Or haven't put it anywhere easy to find from google.
I'm really curious how to estimate the TV one. I gather it's possible based on how much information needs to be transmitted to a tv for the picture to be clear but i'm not entirely sure how much, and how much can be sent by different frequency of radio waves.
posted by Steve at 12:26 PM
6 Comments:
Might be able to use the dimensions of your roof antenna to do it, though tv is radio isn't it? which is several metres which wouldn't work out right. Hmm.
yeah thats my initial thought too. With the same stumping point too. Seems odd
Don't forget that an antanae half or 1/4 (or double, 4x, etc) the length as required to pick up a particular radio frequency will still be effective, although at a diminished capacity.
Also, the different crossbeams on your roof antanae are for different channels. I know the short ones do SBS and channel 31, but not sure about the others.
Mildly interesting trivia: generated radio signals such as those used by TV are polarised, and so to avoid interference some towns require thier residents to mount the antanae virtically rather than horizontally.
Hmm that's interesting. Perhaps the length of the sections rather than their spacing can be used then.
Well yeah... the spacing is largely irrelevant as long as it's sufficient that they don't interfere with each other.
I think he meant the spacing between them because waves can only fit through gaps that are roughly the same size as their wavelengths. But yeah in this case they arent fitting through, they are hitting those bars.
Either way i tried by considering how much info must be sent per second. and got the right order of magnetude
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