Gravity Brainbugs: Galactic Alignment

[Lusankya]

Incidentally, the correct answer to the question as written is 'neither'.

What if it is just a tactical nuke? Or there are hills screening you? You can survive that close then.

The correct answer is still 'don't detonate a nuke near me'. Unless it's going to destroy the lair of a supervillain who's about to enact his plan to destroy the world, but you'd think that if that were the case, then Junghalli would have mentioned it.

[Akkleptos]

Make it a tactical nuke, more than 2 kilometres away, please. Oh, and behind the nearest mountain if you will.


Why these kind of hypothetical situations fail to account for orography still eludes me.

[Junghalli]

Change it 5 or 10 kilometers then. That should shut up the annoying smart-alecs give you a respectable minimum safe distance.

The correct answer is still 'don't detonate a nuke near me'. Unless it's going to destroy the lair of a supervillain who's about to enact his plan to destroy the world, but you'd think that if that were the case, then Junghalli would have mentioned it.

Well, yes, but since the whole point of the question is to determine whether or not a person gets the concept of the inverse square law that option isn't available.

[Lusankya]

Then change the wording so that you don't have 'nuke detonation' and 'survival' in the same sentence. I thought the answer would be Nuke A for a moment, because I parsed 'detonate' into 'defuse', because that's the more natural way to reduce the risk from a nuclear bomb.

If I can do that, then other people can too, and it's supposed to be a test of someone's understanding of th inverse square law, not a test of muddling through poorly worded questions.

[Junghalli]

OK. I see how somebody who read the question really fast could be misled by the phrasing, so in the interests of creating as few throw-off variables as possible I'll reword it.

---

There are two atomic bombs in your vicinity. One of them (bomb A) is 5 km from your position. The other one (bomb B) is twice as far away and three times as powerful. I will detonate one or the other, but I will allow you to pick which one I will detonate so you can maximize your chances of survival. Which one do you want me to detonate?

---

Better?

[Akkleptos]

There are two atomic bombs in your vicinity. One of them (bomb A) is 5 km from your position. The other one (bomb B) is twice as far away and three times as powerful. I will detonate one or the other, but I will allow you to pick which one I will detonate so you can maximize your chances of survival. Which one do you want me to detonate?

Again... The one behind the tallest mountain range, assuming a 100 metre-above-ground detonation.

[Junghalli]

Again... The one behind the tallest mountain range, assuming a 100 metre-above-ground detonation.

Assume you're standing in a flat plain that extends for at least 10 kilometers in every direction from your position.

[RRoan]

Again... The one behind the tallest mountain range, assuming a 100 metre-above-ground detonation.

This is supposed to be about the inverse-square law, not about geography.

[Akkleptos]

Again... The one behind the tallest mountain range, assuming a 100 metre-above-ground detonation.

Assume you're standing in a flat plain that extends for at least 10 kilometers in every direction from your position.

Oh, being it the way you put it, then let me have bomb A, as long as you let have a timely warning and time to hide in a lead-lined 50's fridge, a la Indiana Jones.

This is supposed to be about the inverse-square law, not about geography

Not Geography, but Orography... As Zod put it so eloquently, learn to read.
Nevertheless, given the fact that most of the world has mountains, unlike a significant part of Kansas and other midwestern states, my precision still applies.

Though, of course, the power of the blast would have to radius-out a lot more being farther away, but then, it's three times as powerful. I see a maths-trap here...

[RRoan]

This is supposed to be about the inverse-square law, not about geography

Not Geography, but Orography... As Zod put it so eloquently, learn to read.

geography
–noun, plural -phies.
1. the science dealing with the areal differentiation of the earth's surface, as shown in the character, arrangement, and interrelations over the world of such elements as climate, elevation, soil, vegetation, population, land use, industries, or states, and of the unit areas formed by the complex of these individual elements.
2. the study of this science.
3. the topographical features of a region, usually of the earth, sometimes of the planets.
4. a book dealing with this science or study, as a textbook.
5. the arrangement of features of any complex entity: the geography of the mind.

Maybe you should get a better grasp of english before you accuse people of not reading, hmm? Which still doesn't change the fact that you were knowingly nitpicking a visualization of a basic math problem.

[Winston Blake]

Incidentally, the correct answer to the question as written is 'neither'.

What if it is just a tactical nuke? Or there are hills screening you? You can survive that close then.

Or one could say she's playing on the fact that "which should I detonate" in English can either mean "which one of these" or "which ones out of these".

A similar play would be "Should I detonate A or B?" Answer: "No."

[madd0ct0r]

For fucks sake.

Bomb A is 2km away from you
Bomb B is three times as powerful but is 3Km away from you.
Both are on a flat plain.

Both of them will go boom in 60 seconds.

Which one should I defuse?

[Samuel]

3Km away from you.

A. Bomb B is 1.5 times more deadly to you.

[Surlethe]

Spoiler

Let's suppose A releases E joules of energy in a t-second pulse - P = E/t. A releases P W and B releases 1.5P W. You present a cross-section of area A in m2. The power you absorb from A will be PA/(5e7 m2); the power you absorb from B will be 1.5PA/(1e8 m2). Therefore, the power you absorb from A will be, then, PA(2e-8) W and the power you absorb from B will be PA(1.5e-8). You want to defuse A.

[Simon_Jester]

Make it a tactical nuke, more than 2 kilometres away, please. Oh, and behind the nearest mountain if you will.
Why these kind of hypothetical situations fail to account for orography still eludes me.

Because if you were going to dive for cover, then the question would not be "which bomb," it would be "how many meters of limestone would you like?"

Change it 5 or 10 kilometers then. That should shut up the annoying smart-alecs give you a respectable minimum safe distance.

Well, yes, but since the whole point of the question is to determine whether or not a person gets the concept of the inverse square law that option isn't available.

Use a pair of searchlights and just ask the intensity question, instead of breaking out the nuclear warheads. It cuts down on the distractions.

For fucks sake.

Bomb A is 2km away from you
Bomb B is three times as powerful but is 3Km away from you.
Both are on a flat plain.

Both of them will go boom in 60 seconds.

Which one should I defuse?

3Km away from you.

A. Bomb B is 1.5 times more deadly to you.

Wait, what? Why would I defuse the less deadly bomb?

[Steel]

That makes no sense. An infinitesimally small mass would have to have an arbitrarily high velocity in order for the cross product to be nonzero.

Eeer what? its rxv so this has magnitude |r||v|Sin(t), so as long as v has a non zero component normal to the position it will tend to infinity as |r| tends to infinity, so an arbitrarily small mass can take out arbitrarily high AM. All thats missing is a mechanism in this case.