Comments by "" (@mina86) on "Veritasium" channel.

  1. Meanwhile, in another part of the Universe: ‘I really like the idea that because 20% of the mass of the Universe is Dark Matter, maybe there is an entire Dark Standard Model if you like.’
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  2. Minimising loss is a different question. Take the Brazil v Canada example. That's just betting. You bet one dollar. If you picked Brazil and it wins get two dollars back. If you picked Canada and it wins you get 30. Probability Brazil wins is 80% regardless of your pick. If you’re interested in probabilities, it’s 80:20. If you’re interested in maximising profit, saying Canada is a better strategy.
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  3. Wait, stupid question, how do you make the magnets all attract each other and never repel?
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  4.  @HoustonLucas , ‘I'm saying that halfers and thirders are trying to solve different problems’ – right, and in question as stated at the beginning of the video, the correct answer is 50%.
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  5. 8:00 – this sounds dumb. How is vocabulary question test of intelligence rather than knowledge? This reminds me of the story (I’m too lazy to verify if it’s correct at the moment) where US IQ test was given to other nations who scored lower. Only later someone realised that the test was filled with questions referencing dimes, baseball and other topics which are US-specific.
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  6. Change playback speed to 1×.
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  7.  @JohnDoe-yq9ml , Dark Matter and Dark Energy aren’t excuses for unknown phenomena. They are names we call those phenomena.
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  8. The point of sympathetic prison guard is that they know all the numbers and they strategically swap the cards only if there is a loop longer than 50. And the strategically swap the numbers to break that loop in half. If there is no such loop, they do nothing.
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  9. When you play a video game you care about FPS, not that once a year a glitch happens most of which you won’t even notice.
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  10.  @joaidane , but she doesn’t have more information. She has two relevant pieces of information: 1) a fair coin was flipped and 2) regardless of a result of a coin flip I’m going te be woken up at some point.
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  11.  @mookifacation , the question isn’t what day of the week it is. Or what caused her to be woken up.
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  12.  @adamlaceky8127 , the question is what she believes because the question is asked from the perspective of her knowledge. The flip has already happened by the time she is woken up. So that’s why the question has to be limited to her frame of mind.
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  13.  @olx8654 , only a fool ignores the question and substitutes it with one that fits their world view. An inteligent person understands what the question is about and that if they change it they’ll get a different answer as well. She knows that the three possible events are not independent and thus counting them separately is an example of a sampling bias. If you need help thinking about it, imagine betting for Canada’s win with +400 odds and how that bet affect Canada’s chances (hint: it doesn’t).
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  14. I think the important thing to note is that it's quite obvious that if new medium has the exact same content as the old medium, there will be no improvement. Whether I watch a lecture live or on a TV screen probably makes no difference what so ever (or even I would guess watching it live is better) but what recording gives me is possibility to pause and rewind. So yeah, the question is not what is better, but what is the best way to present the information using given medium.
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  15. I cannot recommend ‘Thinking, Fast and Slow’ by Daniel Kahneman enough.
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  16. More precisely “mechanical energy is not”. ;)
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  17. I actually thought that it depends on the rope, mass, height and some such, but it seems that it does not: a - acceleration at the very bottom h - distance between the starting point and the point when rope starts to stretch x - distance the rope stretches a = kx/m - g => kx = ma + mg E = mg(h + x) W = kxx/2 E = W kxx/2 = mg(h + x) (ma + mg)x/2 = mg(h + x) ax + gx = 2gh + 2gx ax = 2gh + gx a/g = 2h/x + 1 => a/g > 1 => a > g QED
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  18. ½mv²+½Iω² is *not* the initial state. The initial state is ½nu² (where n is mass of the bullet and u is it's speed). So if we ignore heat, we get ½nu² = ½mv² = mgh in the first case and ½nu² = mgh + ½Iω² in the second. To make those work we need to take into consideration non-mechanical energy, and so: ½nu² = mgh + E and ½nu² = mgh + ½Iω² + E'.
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  19. No, “kx/m - g” is acceleration of the jumper, which I designated as “a”. The force of the rope and the force of gravity have opposite direction, hence the subtraction.
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  20. Change playback speed to 1×.
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  21. /watch?v=WQhd05ZVYWg Hawking covered this topic.
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  22.  @olx8654 , ‘ the question being asked of the classifier is what is the probability of the current "waking up" event, not what is the probability of a coinflip.’ – No, that is not the question. The question is: ‘What do you believe is the probability that the coin came up heads?’ It’s at 1:05 in the video.
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  23.  @mookifacation , ‘What if a tails meant she was not woken at all? Should she say 50/50?’ This is not a comparable situation. If tails meant she was not woken up at all, by being woken up she would be given information. In situation as presented in the video, waking up doesn’t give her any information.
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  24.  @M4dmuffin , the premise is that when she is put back to sleep on Monday, she forgets about being woken up.
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  25.  @ShaharHarshuv , she is not asked to guess. And whether she is guessing correctly is not a factor in the problem. The question is what’s the probability the coin came up heads.
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  26. ​ @shiinondogewalker2809 , except that’s a different question. The question is straightforward: What’s the probability coin came up heads? If you rephrase the question you might get a different answer. But as stated, the answer is 50%.
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  27.  @dustinwehr2433 , this is unambiguous question. Just like question of what the colour of the dress was. The dress had specific colour. If you ask what colour the dress appears to you that’s a different story. And if you change question in this scenario you’ll also get different answers.
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  28.  @peterstanbury3833 , what a bizarre concept! Answering question as asked rather than reinterpreting it! ;)
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  29.  @olx8654 , except it’s not. The question is literally about the coin coming up heads.
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  30.  @dustinwehr2433 , yes, like I’ve mentioned, if you change the statement you get a different answer and possibly ambiguous one. Nevertheless, as Mathematics show us, there often is a precise way of translating natural language to proper Maths. After all, proofs are typically written in natural language. This of course touches of another point. Namely that pretty much all philosophy ‘paradoxes’ can be easily resolved by asking the person stating the paradox to define terms they are using. Some are even borderline manipulative with bait and switch sometimes as blatant as ‘if you have two choices and one is taken away from you you have no choice’.
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  31. It does not matter where the block is hit. To get it's centre of mass to height h, mgh of energy needs to be used.
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  32. Hydrogen is just an electron orbiting a proton. Helium on the other hand, was formed by Hydrogen atoms smashing into each other since at the beginning, the whole system was quite hot and dense so it could have occurred.
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  33. > Ever notice how often scientific theory on existance changes? No, I haven't. As far as I can tell, first there were some philosophers doing a guess work (ie. not science), and then when Hubble noticed galaxies are running apart from each other a scientific hypothesis was proposed and now we just test the hypothesis and add more details into it.
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  34. That's not true. One of the factor in how fast a specie evolve is how long does it take for a new generation.
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  35. Interesting how I subscribe to channels of all of those guys. O_o You can't explain that.
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  36.  @JohnDoe-yq9ml , there is no theory of Dark Matter or Dark Energy. Theories which explains those two is what scientists are trying to figure out.
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  37. As Einstein has shown, energy and mass is the same thing, so for quarks and leptons to get created you just need energy. As for where the energy came from, they are many hypothesis. One says there is such a thing as a negative energy and thus the sum energy of the universe is zero, so thanks to quantum fluctuation things could just appear from “nothing” while conservation the energy. The string theory tries to answer the question by saying that big bang was a collision of two branes.
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  38. Derek in Switzerland? Will you be dropping by Zürich by chance? ;)
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  39. Change playback speed to 1×.
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  40.  @Synergyseek , that’s completely different. In this scenario waking up gives her information. In scenario presented in the video, waking up doesn’t give her any information.
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  41.  @WolfspiritMagic , nope. If she’s not awoken when coin lands heads up than once she is awoken she knows that the coin must have landed tails up. If she is woken up regardless, being woken up gives her no new information therefore the probability is 50%.
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  42.  @kirillnikonov6662 , but she is not asked whether it’s heads or tails. She is asked what she believes the probability is. The probability remains 50% just like probability of Brazil winning is 80%.
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  43.  @SylviaRustyFae , her waking up has 100% probability of happening. Regardless if the coin was heads or tails.
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  44.  @SylviaRustyFae , in your earlier comment you’ve said: ‘No one is askin the probability that the coin came up heads or tails tho... The question is the probability that this instance of her bein woken up is the result of a head or tails result’. So you are talking about probability of her being woken up. That probability is 100%. As such, her waking up doesn’t change any probabilities. Just like making a bet in Brazil vs Canada game doesn’t change probability of a win for either team. The question in fact is whether the probability of coin coming up heads. It literally is ‘What do you believe is the probability that the coin came up heads?’.
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  45.  @SylviaRustyFae , no, the question isn’t about the cause of her waking up. The question is about probability of coin coming up heads. That’s literally what she is asked.
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  46.  @SylviaRustyFae , yes, and based on her knowledge that probability is 50%. The fact that the flip has already happened doesn’t change what she knows. If there was a Brazil v Canada game last week, until you check the result, chances of Brazil having won that game is 80%. Same here, unless she has more information, chances that the coin came up heads is 50%.
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  47. We cannot only consider conservative forces, because clearly mechanical energy is not conserved. Inelastic collision is inelastic precisely because there are non-conservative forces involved.
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  48. If you just look at potential energy then yes, but rotating block has kinetic energy associated with the rotation equal to ½Iω² where I is it's moment of inertia and ω is it's angular velocity. This is separate from potential energy (mgh) and kinetic energy associated with linear motion (½mv²).
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  49. Rotation motion is energy and it is kinetic energy. Think of each individual atom. It does not know that it's part of a spinning block. It just goes in some direction and thus has kinetic energy.
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  50. It's charge distribution that is spherical and they have mass because they interact with higgs field.
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  51. I LOVE how the people are genuinely interested.
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  52. Sorry, I somehow misread and thought you were asking about He. The way I understand BBT is that at the beginning forces themselves were all weird and bungled together, but as temperature and density decreased, the forces turned into the familiar four fundamental forces, at which point the universe consisted of elementary particles (quarks and leptons). As the temperature decreases further still, the quarks started binding together into hedrons (which include protons and neutrons).
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  53. “Inertia force”? Uh?
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  54. I don't think it bounces more easily. I think what's happening is that as the bullet hits the side, the block starts moving and “runs away” from the bullet thus the bullet does not go as deep into the block as when it hits the centre in which case the block is slower when “running away” from the bullet. The energy saved on not going as deep into the block is what spins the block.
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  55. This is yet another example why we should never let philosophers out of their caves. 7:45 – that’s called betting. Outcome with lower probability gets bigger payout. And whether you win or loose, the probability of the event remains the same.
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  56.  @natalyabaranova6827 , she is asked ‘what she believes the probability is’ therefore the course of action is to say whatever she believes and get a thousand dollars each time.
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  57.  @natalyabaranova6827 , this is philosophy in a nutshell. State a question with obvious answer and then wave arms around for long enough to confuse people to make them think you have something smart to say.
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  58. YT messed formatting. For full explanation with nicer formatting see pastebin com/8mCHVDp7 (you know where to put dot).
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  59. Gravity has nothing to do with the energy of rotation. Yes, the potential energy remains the same and the centre of mass moves in the same way in both experiments. However, in the second one, the block has more mechanical energy, as the kinetic energy of rotation is a real thing.
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  60. /watch?v=ph8xusY3GTM
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  61.  @TODLectures , no. Entanglement does not allow information to be transmitted.
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  62.  @VariantAEC , how do you know what is the transmission time? You’ve just described two-way measurement where one way is just photon in a vacuum and the other is electromagnetic force in a wire. That doesn’t solve the problem.
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  63.  @VariantAEC , how do you suggest to measure that speed? It’s the same problem all over again. And if you want to calculate it you will need to know speed of light. PS. You seem to be confusing speed of electrons in a wire (which is comparatively slow) with speed of signal propagation in a wire (which is quite a substantial fraction of the speed of light).
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  64.  @VariantAEC , we know the speed the same way we know the speed of light.
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  65.  @VariantAEC , different parts of a computer are akin to Earth and Mars in the analogy used in the video. Any speed measured is either two-way (where signal comes in, gets processed and then is measured at the end) or needs to rely on time synchronisation of different parts of a circuit.
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  66.  @VariantAEC , they rely on timing but not on one-way speed. But, well, I’ve tried. I don’t see how I can help you further. Maybe someone else will be able to better explain it to you.
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  67. Please include links to all mentioned links in comments as well. For one, on mobile one cannot click on the pop-ups on the video.
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  68. Damn, I was expecting a trailer for a full length Veritasium: The Science movie… That would be so cool. :)
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  69. Change playback speed to 1×.
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  70. To anyone thinking sound A is higher, make sure you have playback speed at 1×.
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  71. It's an inelastic collision meaning that the energy is not preserved (or more precisely kinetic energy is changed into heat) but the momentum is. So it's not that the one rotating has additional energy, it's the opposite, the one that is not rotating has less mechanic energy. If we take heat into account both blocks have the same energy, and the one that is not rotating has hotter.
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  72. Obviously, the rotation energy is taken from the bullet's energy and that's not a mystery. Point is, however, that there is no change in linear momentum.
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  73. With an impulse of force F lasting time t instead of a bullet then the rotating block will go lower because in the first case the force is only used for linear acceleration whereas in the second it's also used for rotation. That's different from the experiment on the video where an inelastic collision happens and some of the energy carried by the bullet is changed into heat. And they two are not “completely different”. They are separate experiments but with a very similar initial conditions.
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  74. Change playback speed to 1×.
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