[Archive!] Pure mathematics, physics, chemistry, etc.: brain-training problems not related to trade in any way - page 198
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I uncovered it a long time ago. The wire consists of two wires. Each core carries current equal in magnitude but opposite in direction.
The field of one core fully compensates the field of the other core. The distance between the cores is much smaller than the distance from the core to the compass,
so the compass doesn't show anything.
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That's why I asked what you're designing. If you are involved in room projects, you probably know about the magnetic field strengths of underfloor heating, where it is better to use a two-core cable:
http://www.teplolux.ua/teplye_poly.htm (at the end of the page).
A crook and a thug. I had to dig through the branch.
Question: Why is the current flowing through the wire, but the compass does not indicate the presence of a magnetic field?
Found a follow-up discussion.
The mystery of the non-magnetic wire is not solved, but my question fell away.
With the lamp and the clamp meter, there's a catch, too. Either it is the device mode or there is another lamp hidden behind the first one.
There are all kinds of current clamps.
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Tomorrow.
Okay. Tomorrow. No catch here. The current of a 36W bulb - let's say around 300mA.
Let the clamps stand on the 1A range. The current frequency is the usual - 50Hz. No second bulbs.
Here, by the way, is another exam question for students, a similar one:
The pliers are put on the electrolyser. A voltage is applied to the electrodes of the electrolyser. A current is flowing through the wires to the electrolyser electrodes.
Will the pliers show it?
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А чего там с треугольником правильным? Моё решение проигнорировано как-то. Я не понял - намёк что неправильное? Или наоборот - "зачёдбэзвапросов"?
"Zachodnosvaprosamy". Sorry, I didn't reply to your last post with "homothety rules": I still haven't had time to come up with solutions with homothety (I got too carried away with the Mandavoha problem). I'll check your solution - I'll definitely write back.
P.S. This problem with the square in the triangle is also on the geometrical transformations.
P.P.S. Got it(here). Super! Fundamental! A couple of thoughts:
1. Criterion circles by the very nature of their construction have radii, equal to the radius of our Y. Their centres are constructed even simpler - by intersecting arcs of circles from A and O with radii of AO.
2. It is not obvious that these geometrical places are exactly circles. But it is very easy to prove it analytically.
2 alsu - regarding construction of triangle by sidelines and bisector: I see that direct construction of geometrical places becomes a popular method for solving problems here :)
One more thing about mucic. The problem is amazing by unexpectedness of the result - if you don't see the basic formula for partial sum of a harmonic series. I should not have written out the solution at once, but I should have written it down strictly for you with this formula, so that people would have a hard time :) There are a couple of considerations:
1. A muzik can crawl even not with constant speed, but slow down - and still be able to reach the other end of the hose. Let's say it travels 0.01/ln(n+1) m for every second, then the row will still diverge.
2. The divergence of the series is a non-critical condition for the success of the mucic. It is certainly sufficient, but not necessary. The main thing is that the partial sum of the series in brackets ever reaches 100, i.e. the alpha reaches exactly 1. At that point the mucic can stop moving and retire. Therefore it can slow down even more intensely than by the law of the inverse logarithm - for example, by a power function like 0.01*n^(-epsilon).
Another one (simple).
The island is shaped like an acute angle. The woodsman needs to walk to each of the two shores and return to his hut. How should he walk to cover the shortest distance?
Another one (simple).
The island is shaped like an acute angle. The forester needs to walk to each of the two shores and return to his hut. How should he walk to cover the shortest distance?
Along the perimeter, probably.
Question: Can a diamond be cut with a jet of clean air at no more than 3 atmospheres?
Question: Can a bolt with 27 threads (turns) be unscrewed with 3 turns without breaking it, if the bolt
was tightened all the way to 27 threads?
Вопрос: можно ли разрезать алмаз струёй чистого воздуха под давлением не более 3х атмосфер?
it is possible if the temperature of the jet exceeds 850 degrees Celsius