Which was more expensive, the atomic bombing of Hiroshima or the firebombing raid on Tokyo in 1943?

It depends what you mean by cost. The total cost of the Manhattan Project was $2 billion. So if you apportion half of that to Hiroshima, that's $1 billion, far more than the cost of the ordnance dropped on the single Tokyo raid..

But only 10% of that cost was actually for the construction of the bombs, so again, 10% of $1 billion is $100 million.

There were multiple Tokyo raids, from the small Doolittle raid in 1942,

I assume the Raid you are referring to though is Operation Meetinghouse, March 9–10 1944, during which 1665 tons of bombs were dropped by 282 B-29s that actually made it to the target. I was not able to find the cost of the ordnance used, but if you divide $100 million by 1665 tons, you get about $60 thousand dollars per ton. These were mostly 500 pound bombs, so that would mean $15,000 per bomb in order to equal the cost of the Hiroshima bomb.

I doubt those conventional incendiary bombs cost $15k each, but I could be wrong. Someone more familiar with WW2 ordnance cost may know more, but I seem to recall that torpedoes cost around $20k, and they are far more complicated, obviously.

Again, I’d welcome comments. I think my methodology is solid, just not sure about the unit cost of an E-46 cluster bomb, or the smaller and cheaper 100 pound M47 incendiaries.

Fun Fact: The overall cost of the Manhattan Project, that developed atomic weapons, was $2 billion dollars ($27 billion 2016 dollars)

The plane that carried the bombs, the Boeing B-29 Superfortress, had an overal development cost $3 billion dollars ($41+ billion 2016 dollars)

So the plane development cost more than the bomb development (some estimates put B-29 costs at $3.7 billion ($50+ billion 2016 dollars), and was the most costly single weapon development project in WW2.

What should be my basic book for engineering mathematics? (ECE)

Thanks for the A2A.

Well, this essentially depends on how comfortable you are with Mathematics.

Though, the recommended book for Engineering Mathematics in NSIT is Advanced Engineering Mathematics by Jaggi and Mathur , however you can also use Erwin Kreyzig Advanced Engineering Mathematics which is also recommended.

Another book widely recommended is Engineering Mathematics by BS Grewal .

An important thing to note is that you do not need to refer ALL the books.

Just choose one book and stay with it, otherwise it may lead to confusion.

All the best!

What is the essence of Homo sapiens?

Humans are the most aggressive competitor on the planet. We are also the least content, and unhappiest creatures.

Content and happy creatures don’t convert tools into weapons, routinely murder members of their species, go to war, build nuclear weapons, or go to the moon.

Why do I still lose weight no matter how much I eat?

You should refine your question. The way you currently state it is like you weight for example 90 kilos, start losing weight, eat more to compensate, still lose weight, eat even more to compensate, lose even more weight, and so forth until you become a twig.

In that case the question would be, how did you get to this 90kg in the first place…

But if you for no appearent reason lose weight and keep on doing so, I would certainly visit a doctor and demand a proper examination.

If this is about not gaining weight while you eat a lot, try to do this:

  1. Start lifting heavy weight every other day
  2. Double you daily foodintake
  3. Sleep 8 hours a night

Good luck!

What is the difference between the Java functions Math.rint() and Math.round()?

As far as my knowledge i can tell only 1 difference between these 2 functions. i would like to prove it by an example

double n1=1.5

double n2=1.3;

System.out.println(math.rint(n1)); //output is 1.0

System.out.println(math.rint(n2)); // output is 1.0

System.out.println(math.round(n1)); //output is 2

System.out.println(math.round(n2)); //output is 1

As you can see the difference comes during .5 where rint returns the rounded down value basically a double value whereas round returns the rounded up whole number.

Now that we recently enjoyed the lovely, gay, Muslim wedding in the UK, will this allow many more gay Muslim men coming out to marry each other?

One of them was a muslim and it took place in a registry office, not sure about any reception details so I’m not sure that is really a muslim wedding. That said, they are getting acid attacks and facing hostility in the streets.

If I was a gay muslim I’d keep a low profile. There has been other gay muslim couples that married or civil partnered before, they just tended to keep a lower profile. So I can’t see the floodgates opening as British muslims are not supportive and there is a fringe of them who are especially hostile.

What percentage of Greek Macedonians were Slavophones in the early 1900's?

We have statistics published in a Belgian magazine from 1912 (De Godsdiensten op den Balkan.), just before the Balkan wars divided up Macedonia, and cited in Manastir Vilayet – Wikipedia and Salonica Vilayet – Wikipedia. Of course, the Ottoman Vilayets do not coincide with the modern borders: Salonica Vilayet is now 3/4 Modern Greece, 1/4 Bulgaria; Manastir Vilayet is 1/2 Greece, 1/2 FYRO Macedonia.

The stats in 1912 were:

  • Salonica Vilayet: Orthodox Greeks: 168k, Orthodox + Muslim Bulgarians: 144k
  • Manastir Vilayet: Orthodox Greeks: 62k, Orthodox + Muslim Bulgarians: 355k

As a result of the Balkan wars, Slavic-speakers in the part of the erstwhile Salonica Vilayet that was incorporated into Greece were subject to population exchanges with Bulgaria. As Niko Vasileas' answer reports, that involved 66k Slavic-speakers; Slavic speakers of Greek Macedonia – Wikipedia puts the total from 1900–1920 at over 100k. People who read me here will be familiar with my constant quoting of The Tale Of The Stairs; its author, Hristo Smirnenski, was born in Kilkis (Bulgarian Kukush), now in Greece.

The Slavic-speakers in the part of the erstwhile Manastir Vilayet that was incorporated into Greece were not subject to population exchange, and they constitute the Slavonic-speaking minority present in Western Greek Macedonia.

Slavic speakers of Greek Macedonia – Wikipedia:

The 1928 census recorded 81,844 Slavo-Macedonian speakers or 1.3% of the population of Greece, distinct from 16,755 Bulgarian speakers. Contemporary unofficial Greek reports state that there were 200,000 "Bulgarian"-speaking inhabitants of Macedonia, of whom 90,000 lack Greek national identity. The bulk of the Slavo-Macedonian minority was concentrated in West Macedonia. The census reported that there were 38,562 of them in the nome of Florina or 31% of the total population and 19,537 in the nome of Edessa (Pella) or 20% of the population. According to the prefect of Florina, in 1930 there were 76,370 (61%), of whom 61,950 (or 49% of the population) lacked Greek national identity.

Of course, the 1928 census was conducted after the 1922 population exchanges, where Muslims in Greece were exchanged with Christians from Anatolia speaking Greek, Turkish, and in one idiosyncratic instance Bulgarian (Ἡλληνιστεύκοντος). The majority of arriving refugees settled in Macedonia, though the majority of departing refugees were also from Macedonia. So the proportions reported in the 1928 are likely smaller than they were in 1920.

That said, the prefectures of Florina and Pella were not traditionally Greek-speaking at all: the Greek–Slavic linguistic boundary ran south of them, halfway through Kastoria and Kozani, and most of Thessaloniki prefectures. (See the description in Sandfeld’s Linguistique Balkanique.) See e.g. https://upload.wikimedia.org/wik…

What is the physics behind losing mobile network connectivity when a train passes by?

I am the one who asked this question a while ago.

(skip the italics to get right to the probably-maybe-sortof-answer; see question comment for details)

This is a question for which I had found no satisfactory answers. It surprised me that even a thorough google search did not shed any light on this everyday phenomena. So I came here and posted this question. But in here too,answers evaded me. I began requesting answers. Still,no replies. So this question had quiescent for several months,almost ignored ,and I felt like it had been tucked away to the corner of some digital labyrinth of questions in the digital quora world(with digital dust collecting over it of course).

So,one day ,scrolling through Quora ,I saw The Jack Fraser taking questions. This question,this unanswered question that had been bugging me for a while,quickly sprung out from the back of my head. I send him a message,and lo and behold, he was kind enough to send me a link to a relevant forum discussion. Even though I have no technical background in Physics or Electronics (except for my high school knowledge of both, and maybe a bit more from a few popular science books),I finally have been pointed to the possible cause of this disturbance.

Lets break it down.

The Railway.


  • Over head high tension wire (~25 kV) that powers the train.
  • Pantograph, which is the Antenna-like thing on top of the train that taps the electricity from the overhead wire.
  • Rails,through which the return current passes.

The phone

The mobile phone depends on exposure to the electromagnetic waves coming from the mobile tower to induce currents in its antenna ,so that those electromagnetic waves can be converted into sound signals which they stand for (the voice from the other end).

Note: This image is not for reproduction. I repeat. Don’t take that risk.

Now,suppose a train passes by. When you have such electric fields (from the wires above),and moving charges (the electricity flowing from the over head lines to the pantograph to the train and finally into the metallic rails),a lot of electromagnetic waves are emitted. These electromagnetic waves spread out from its source and find its way near you where it is picked up by the antenna of your mobile phone.

When a metal gets hit by electromagnetic waves,tiny electric currents are set up within it. Same thing happens with any antenna.

Now when the antenna picks up these electromagnetic waves,its not picking up the signals coming from the mobile tower,rather,it is picking up the waves generated by the train . Hence,you do not hear the voice on the other end.

This is also the reason you lose your internet connectivity or your internet speed when a train passes by.

This interference set up by the electromagnetic waves is called Repetitive Electrical Impulse Noise or REIN for short.

In fact,this is also the reason your home DSL modems lose connectivity when a train passes by. The REIN “causes interference which in turn causes a DSL modem to mount up CRC errors. This eventually causes DSL synchronisation to drop.”

REIN is not only caused by trains whizzing past you. Even faulty electrical equipments in your home may interfere with your modem.

Hope I have shed light,at least partly on this mystery. Edits,suggestions,corrections are all welcome.

Keep reading guys.


Repetitive Electrical Impulse Noise – Wikipedia

WiFi disruption from passing trains

Is there any visible evolutionary trait that occurred in humans in the last 2000 years?

When we talk about physical traits then range of 2000 years are too small to show the possible changes in physical traits. Evolutionary traits also means changed cultural and social traits. Even growth of Scientific knowledge is also a type of evolution.

Cultural evolution has made humans to live together and become more socialized and more connected to each other in comparison to other animals where still they fight for area issues (:( we still prove we are animals by fighting though).

Social evolution on the other hands is more of less related to cultural evolution, while cultural evolution happens with the basic unit being “and individual “, the basic unit of social evolution is population itself. Population learned to protect its own members and division of labours etcetera.

Scientific evolution has got nothing to explain, it's scientific evolution that makes this question being answered here by ME on quora. XD