[Archive!] Pure mathematics, physics, chemistry, etc.: brain-training problems not related to trade in any way - page 105
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То-есть электромагнит постоянного тока - фикция?
Oops. I didn't think it through. Then there's only one option - the field generated by the wire is in the same direction as the earth's magnetic field.
You have to rotate the wire :)
Oops. I didn't think it through. Then there's only one option - the field generated by the wire is in the same direction as the earth's magnetic field.
You have to rotate the wire :)
Here's a hint. The earth's magnetic field has nothing to do with it. It is very weak and the 10A current creates a magnetic field many times higher. But why doesn't the compass detect it?
Another hint: look at the power wire of your TV, radio, printer etc.
Подсказываю. Магнитное поле Земли тут непричём. Оно очень слабо, а ток 10А создаёт магнитное поле многократно выше. Но, вот почему не обнаруживает его компас?
Ещё подсказка: посмотрите на провод питания телевизора, радиоприёмника, принтера и т.п.
Well, that's a bit of a stretch. First of all, it was talking about direct current. Secondly, it was a single wire.
In any case, that AC current, even in several parallel conductors, phoned quite strongly.
And the presence of a second conductor in a direct current does not guarantee the absence of a magnetic field outside the conductor system.
>Why did the ball float?
Because the pressure increased.
>How will the power consumption of the fan change if its outlet is completely shut off?
Not much, it will just stop pumping air through it.
>Why is there current flowing through the wire but no magnetic field indicated by the compass?
Because there is no load.
1. When the water was poured in, the ball floated up as a result of agitation. But when it touched the surface, it stuck to it as a result of surface tension forces. The change in pressure had nothing to do with it.
2. Practically, it has nothing to do with pressure change. Simply, the energy consumed will not be converted into mechanical energy (air flow) but into thermal energy.
3. The compass is not positioned correctly, its plane is perpendicular to the direction of the force line. The arrow simply cannot show this direction. But it will if the force line is in the plane of the compass, or at least has a component in that plane.
DC transformers do exist, e.g. DC/DC converters .
But, their operating principle is different from that of simple AC magnetic transformers.
Here's a problem.
Propose a function that would have the following properties:
1. F(x=0) = 0
2. F(x) << 1 on the interval [0, a]
3. F(x) increases monotonically on the interval [a, b]
4. F(x) -> 1 asymptotically at x >b
I want to make a wizard with "good" behavior. Preferably the function should be algebraic, i.e. without trigonometry, logarithms and exponents.
Answer to task 10
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The whole point is that the wire is multi-core. Power wires for televisions, monitors, computers, etc. appliances are either three-core (phase, neutral, protection) or 2-core (neutral, phase). The current in the 1st core is the same as in the 2nd core, so the magnetic fields they generate are equal in magnitude and fully compensated by each other because these currents always flow in different directions.
The sum of the currents in all cores of a cable or wire is zero.
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xeon, if there is a load, then there is a current. You are just confused with voltage. Just because there is voltage on a wire doesn't mean there is current in it.
MetaDriver, can the magnetic field created by the wire compensate for the ground magnetic field? Yes. But as I said, the earth's field is very small. So, with a small current in the conductor it is quite possible.
vegetate, Yurixx, indeed a compass will not detect the field of a conductor if it is located "wrong".
vegetate, I agree with you about parallel conductors, however it is impossible to take everything into account in the conditions of the problem.
Answer to task 8
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The answer is simple - the density of the water has changed. But why has it changed, since the temperature of the water is the same? The reason is that the bucket was filled not with ordinary light water but with heavy water. Heavy water is water based on deuterium, a heavy isotope of hydrogen. This water has a higher density than ordinary water. The condition does not say what kind of water was poured. All it says is that it is pure. And the density of the balloon was simply less than that of heavy water, so it floated up. Yurixx, what you described is indeed possible, let's consider it as the 2nd answer to this problem.
Есть такая задачка.
Предложите функцию, которая бы имела следующие свойства:
1. F(x=0) = 0
2. F(x) << 1 на интервале [0, a]
3. F(x) монотонно возрастает на интервале [a, b]
4. F(x) -> 1 ассимптотически при x >b
Хочу сделать машку с "хорошим" поведением. Желательно чтобы функция была алгебраической, т.е. без тригонометрии, логарифмов и экспонент.
Something like an arctangent shifted far to the right, compressed pi times and raised up so that the lower asymptote is zero.
If it is algebraic, then it is not a polynomial (condition 4 is violated), but the ratio of two polynomials of equal powers.
We have to think about it.