[Archive!] Pure mathematics, physics, chemistry, etc.: brain-training problems not related to trade in any way - page 82

 

Look:

 

The ancient Indians used to prove theorems by drawing a diagram and writing "Look" next to it.

 

For the sake of clarity:

 

ANSWER to problem 5, about the two light bulbs:

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Now took 2 bulbs of 100W each and tried it myself. The current in the case of one bulb is 0.40A, the current in the case of 2 bulbs is 0.275A.

Note, not 0.40/2=0.2A, but slightly more - 0.275A. Which means that you, dear colleagues lea and vegetate are slightly wrong.

The current will most likely be not 0.5A, but somewhere around 1.375 times larger, i.e. about 0.687A.

Now, let me explain why this is the case. You'd be right if they weren't light bulbs, but, say, ideal resistors,

whose magnitudes don't change with temperature, but bulbs do change with temperature, they're non-linear.

I've written about this before when I was talking about the electric heat sink. So that's the physics of it. If you don't believe me, try it.

 
Richie >>:

ОТВЕТ на задачу №5, про две лампочки:

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Сейчас взял 2 лампочки мощностью по 100 Вт и попробовал сам. Ток в случае одной лампочки - 0,40 А, ток в случае 2х лампочек - 0,275 А.

Обратите внимание, не 0,40/2=0,2 А, а несколько больше - 0,275А. А это значит, что вы, дорогие коллеги lea и vegetate немного ошиблись.

Ток скорее всего будет не 0,5 А, а где-то в 1,375 раз больше, т.е. около 0,687 А.

А теперь, объясню почему так получается. Вы были бы правы, если бы это были не лампочки, а скажем идеальные сопротивления,

величины которых не меняются от температуры, а у лампочек сопротивления меняются в зависимости от температуры, они нелинейны.

Об этом я уже писал ранее, когда речь шла о электрическом радиаторе. Вот такая вот физика получается. Кто не верит - попробуйте.

However, yeah. Less current - less heat - less resistance - more current :) the truth is out there %)

 

ANSWER to problem 4, about the two gas cylinders:

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The correct answer was given first bysanyooooook . Indeed, the 2nd cylinder would remain heavier and indeed they would have the samemasses if they were turned upside down with the valves. I will explain why. The thing is that the gas in such cylinders is in 2 states at once - liquid and gaseous. The liquid phase flows only if the cylinders are turned upside down.

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To be honest, I didn't quite understand your answer at once. But, strangely enough, you are right too. The transition would indeed be continuous.

However, what you are talking about will take a very long time, that's the reality.

 
Do you need answers to problems 6 and 7?
 
Mathemat, I've been trying to understand such a thing for a long time. Maybe you can explain it to me. What do Fibonacci numbers have to do with forex anyway?
 

Richie, we don't talk about Forex in this thread. There are authorities in Fibs on Forex, you'd better ask them, because they use Fibs for real.

About the Fibonacci numbers themselves, please, I can give you a problem or two.

 
Mathemat писал(а) >>

Richie, we don't talk about Fora in this thread. There are authorities in Fibs on Forex, it is better to ask them, because they use Fibs for real.

Fibonacci numbers themselves - please, I can give you some problems.

Okay. I talked to such authorities, one known, resembled strongly the bandit and could not explain anything and said: "I can not" :)

Reason: