You do it with trigonometry, though I have no idea what that page of numbers means
Science questions not worth a thread I: I'm a moron!
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You do it with trigonometry, though I have no idea what that page of numbers means
PlutonianEmpire
King of the Plutonian Empire
Actually, I posted my question on more scientifically-inclined website forum too, and got an easy-to-understand reply. Thank you for trying to help.You do it with trigonometry, though I have no idea what that page of numbers means
Actually, I posted my question on more scientifically-inclined website forum too, and got an easy-to-understand reply. Thank you for trying to help.
I´d be interested in the solution too. Could you link to it?
You compare the star's position from two observations made at two points in the Earth's orbit. The difference in position creates two angles of a triangle. With that, and the fact you know the two measurements were taken 2 AU apart, you can determine the star's distance.
Think of it like a 3D camera -- there's two lenses that record slightly different pictures.
PlutonianEmpire
King of the Plutonian Empire
Here: http://www.shatters.net/forum/viewtopic.php?f=15&t=16804
Sadly, the site, at the time of me posting this, the site has crashed (CFC ain't the only one with server issues), and when the site crashes on weekends, it's normally not back up until Monday.
(I got the link from a subscription notice e-mail.)
GoodGame
Red, White, & Blue, baby!
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If I remember right the principle is that you vary the position of a magnet (i.e. windigs on a rotor) within a larger magnetic field (i.e. larger static magnet adjacent to the rotor) and that generates a variable magnetic field that co-propagates an electric field which can be captured as electrical current.
I think it boils down to maximizing the number of magnetic "windigs" you have per surface volume of the central rotor versus the amount of kinetic energy you have to input into turning the rotor within a magnetic field. Probably a surface area versus size of static magnetic field that you can generate versus the mass of the rotor (which directly relates to the kinetic energy needed to rotate the rotor).
So under that theory a large diameter rotor would be more efficient than a small diameter one?
meromorph
Chieftain
Right, the voltage induced in the coil is proportional to the rate of change of the magnetic flux. The magnetic flux is proportional to cross sectional area (perpendicular to the magnetic field). As a formula:
EMF = - N d/dt (magnetic flux)
where N is the number of coils per unit length
The larger rotor will deliver more electric power at a given RPM than the small rotor. But by itself this doesn't necessarily make it more efficient, since in both cases we have
power out = power in - losses
The losses are mostly due to friction, and also resistive losses. The electrical power lost to resistance heating is P = i^2 R, so it is better to have a low current at a high voltage (which corresponds to the larger rotor). The friction depends on the velocity (higher RPM will have more friction) and the contact area of the axle (large rotor will have more area and more friction). This is why it's hard to give a general answer, but the friction due to the rotational speed of the rotor is the most limiting factor, and to generate more power at a given speed requires a larger rotor.
rugbyLEAGUEfan
Deity
Why does cottage cheese develop little pools of water in the tub once the first spoonful has been consumed and returned to the fridge ? It's not "melting" and it's consistency never changes until a spoonful has been taken .
In retrospect this question probably is worthy of it's own thread
In retrospect this question probably is worthy of it's own thread
Are any moons known that have satellites of their own?
SS-18 ICBM
Oscillator
Maybe it's because it's been opened. A spoonful taken out would provide air though. How dry is it where you live?
rugbyLEAGUEfan
Deity
It's not just the opening ( I actually tested by opening a tub but not taking a spoonful . It remained unchanged) . It's not particularly dry but does this matter since it's in the fridge ?
Could it be in anyway related to the phenomena whereby an ice cream cone tends to melt a lot quicker once the first lick is taken but can retain it's integrity for quite a while unlicked ?
Could it be in anyway related to the phenomena whereby an ice cream cone tends to melt a lot quicker once the first lick is taken but can retain it's integrity for quite a while unlicked ?
GoodGame
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I'm not an engineer, so I defer to meromorph or an engineer. I don't think there's an easy answer as in small vs large since there's probably at least three variables that factor into the (mass of the rotor, most efficient use of the surface volume of the rotor as a place to hang 'windigs", and also the static magnet).
I don't think so... Nor do I think a stable orbit is likely to form. The planet [A] the satellite is orbiting is going to have a much stronger pull on a hypothetical satellite's satellite [C] than the satellite itself. Thus, the body [C] would probably escape the gravitational pull of the primary satellite and just orbit the planet [A] proper.
However, there's plenty of examples of stable three-body problems (Sun / Earth / Moon for the obvious example) that I'd imagine such a scenario is possible. Of course, my knowledge of physics is pretty limited....
(edited for clarity)
When you take a spoonful, are you leaving a depression in the container? Er, what I'm trying to ask is that are you leaving an uneven surface where the whey can pool?
rugbyLEAGUEfan
Deity
Yes . Cottage cheese is pretty thick so it just leaves a large scoop
Try this. Open a container, take a scoop, but then mix the container up, leaving an even surface. Does whey still pool in the same manner?
rugbyLEAGUEfan
Deity
I'm kinda embarrassed that this has taken up so much of the thread as I acknowledge this is not one of the pressing scientific questions of our time . But Contre , we've come this far so let's hopefully get there .
Yes , when I flattened out the tub as best I could , this watery stuff still forms in the tiny little depressions left due to the lumpy nature of cottage cheese . Unquestionably the water does not form until 1. The tub is opened and 2. A scoop is taken .
I'll pour it out before having a serve , and sure enough it's there next time .
Yes , when I flattened out the tub as best I could , this watery stuff still forms in the tiny little depressions left due to the lumpy nature of cottage cheese . Unquestionably the water does not form until 1. The tub is opened and 2. A scoop is taken .
I'll pour it out before having a serve , and sure enough it's there next time .
I googled watery cottage cheese but after half the results had vagina or discharge in the title, I closed the window. Enjoy your cottage cheese now.
Okay in seriousness, I'd recommend emailing the company. I'd be curious as to the result.
Okay in seriousness, I'd recommend emailing the company. I'd be curious as to the result.
GoodGame
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I'd describe cottage cheese as cheese + water. It is a colloidal mixture (non-homogenous mixture) of cheese curd and whey (probably another colloid?). I'd buy what SS-ICBM was getting at in that you allow oxygen/air pressure into the container once you pop off the protective plastic film on a new container. Over time maybe that air pressure presses the water out. In a way you are getting a more proper cheese from your cottage cheese! 
Alternatively, is there an active microbial processes in cottage cheese? Does popping the lid allow oxygen in which allows some further fermentation (the cottage cheese basically is partly fermented cheese)?
It's definitely not a phase change-the increase in water separation does not represent a phase change, unless you actually froze the cottage cheese first. Nothing is melting.
To be snippy: IMHO, complaining about the water separation in cottage cheese it is like complaining about the way specific nuts self-filter as you eat a tin of mixed nuts.
Alternatively, is there an active microbial processes in cottage cheese? Does popping the lid allow oxygen in which allows some further fermentation (the cottage cheese basically is partly fermented cheese)?
It's definitely not a phase change-the increase in water separation does not represent a phase change, unless you actually froze the cottage cheese first. Nothing is melting.
To be snippy: IMHO, complaining about the water separation in cottage cheese it is like complaining about the way specific nuts self-filter as you eat a tin of mixed nuts.
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