Samuel Hapák

Karma: 201

Samuel Hapák 21 Dec 2024 23:11 UTC
−1 points
0
in reply to: Shankar Sivarajan’s comment on: Elon Musk and Solar Futurism
No. Nuclear plant has a fixed output, zero elasticity of production. It has to sell all the electricity it produces, even if it should sell it for 0.

But, it doesn’t really matter. There certainly exists such a day price that nuclear is competitive with solar and is able to sell the same amount of produce as before.

Samuel Hapák 21 Dec 2024 15:57 UTC
3 points
0
in reply to: greylag’s comment on: Elon Musk and Solar Futurism
No. Average price must go down. The evening price might go up—it might go up even to the level where the average price doesn’t change at all, but it can’t go up to the level where average price would rise.

Think about it. You run a nuclear plant. Suddenly, due to solar competition, the day price went to 10%. You can’t turn nuclear off just during the day, so you keep it running and lower your day price to 10% as well. Your costs didn’t change, so to keep the same level of profitability, you need to rise the night price to 190%. This way your revenue doesn’t change.

There is no reason why you would be able to rise the price above that level.

Samuel Hapák 26 Nov 2024 1:58 UTC
3 points
−2
on: a space habitat design
I don’t get what is the issue with rotating cylinder and stability. As I imagine the cylinder, it has radius << length, thus his axis of rotation will be the one with the smallest possible moment of innertia and thus should be stable.

Dzhanibekov effect applies only to 2nd principal axis so should be relevant only for cylinders with radius similar to length.

Samuel Hapák 19 Sep 2024 21:36 UTC
1 point
0
on: Monthly Roundup #22: September 2024
The thumbnail is framed as super important, a critical component that creates other criticials, and needs to be in place in advance. Feels weird that you can’t go back and modify it later if the video changes?

The idea is that you want to have a high CTR, so you need to have a good thumbnail. If you do a video that can’t be turned into a best thumbnail possible, you are screwed. The only way to fix this is to redo the video. Thus, that’s the reason you should start with thumbnail.

Samuel Hapák 1 Mar 2024 19:19 UTC
10 points
5
on: The Parable Of The Fallen Pendulum—Part 1
I guess the didn’t have their programming class yet😂

If you wrote a C program and it doesn’t do what you predicted, would you assume that your compiler is broken or that you made a mistake? If I got a dollar for every time someone wrongly complained that “there is a bug in compiler”…

World is complex. We use theory to build models describing the reality and compare their predictions with experiment. If you notice mismatch between model and experiment, it might be a problem with:
1. Your experiment.
2. Your model.
3. Or your theory.
You have to further dissect and understand the root cause of the mismatch before you make any judgement.

Samuel Hapák 19 Feb 2024 12:00 UTC
7 points
7
on: Weighing reputational and moral consequences of leaving Russia or staying
Run away while you still can. Yeah, it’s scary. And heartbreaking. But you might not have that opportunity later on.

Take everyone with you whom you can.

You don’t have to run to some extremely different country/culture. There is lots of relatively wealthy Slavic countries in the Central Europe.

And talented programmers can always find job here.

Let me know if you need help with that.

Samuel Hapák 24 Jan 2024 17:54 UTC
2 points
0
on: Monthly Roundup #14: January 2024
The plug map is wrong. Gibraltar is using British plugs and should be purple.

Samuel Hapák 18 Jan 2024 11:03 UTC
3 points
0
in reply to: qvalq’s comment on: An Actually Intuitive Explanation of the Oberth Effect
Well, the correct question is “What is energy”. And the answer is that energy is some number that we can compute for any physical system and it doesn’t change no matter what as long as the system is reasonably isolated from its surroundings. Kinetic energy is just a portion of this quantity we can compute for something that is moving.

It’s not very intuitive honestly. The best explanation for what energy is I ever read is this one from Feynman:

https://www.feynmanlectures.caltech.edu/I_04.html

Samuel Hapák 11 Jan 2024 23:37 UTC
2 points
0
on: An Actually Intuitive Explanation of the Oberth Effect
It feels to me that you lack a good intuition for how kinetic energy, momentum conservation,, Newton laws, and Galileo’s relativity all play together and this is causing you confusion.
Relativity says that there is no objective notion of “being still”. We can’t objectively distinguish between being still and moving at constant velocity (same speed, same direction).
2nd Newton law: Force is equal to mass times acceleration: $F = m a$ .
3nd Newton law: All forces in the nature exhibit the property that if object A acts on B with a force F, then B acts on A with exactly opposite force.
1st Newton law is boring, it just says that if F = 0, then a = 0.
Force and Energy are tied together through the concept of work which says that change in objects energy = work received by that object. And formula for work is $W = F \cdot Δ s$ , notice the dot product here! Force perpendicular to movement doesn’t make any impact on energy.
Putting all of this together, it’s useful for you to do following exercises:
1. Try to derive the formula for kinetic energy.
2. Try to derive the formula for potential energy in the gravitational field of Earth near the surface (neglecting change of gravitational force with height).
3. Try to derive the law of conservation of momentum.
Once you do the three above, I have a tricky paradox problem for you to solve:
Imagine two cars driving on the road with the speed $v$ . Suddenly the first car accelerates to double the speed, thus travelling $2 v$ . This naturally required consumption of energy in the form of fuel. The change in kinetic energy was: $Δ E = \frac{1}{2} m (2 v)^{2} - \frac{1}{2} m v^{2} = \frac{3}{2} m v^{2}$ and this should somehow correspond to the amount of the fuel consumed.
However, from the point of the view of the second driver, the car was starting still and accelerated to the velocity $v$ , thus the change in energy is simply $Δ E = \frac{1}{2} m v^{2}$ .
But, this is paradox. It’s not possible that the car would spend 3 times less fuel from the point of view of the other car than from the point of view of the observer standing still on the ground.
Can you explain this paradox?

Samuel Hapák 11 Jan 2024 23:17 UTC
1 point
0
in reply to: qvalq’s comment on: An Actually Intuitive Explanation of the Oberth Effect
That’s an excellent question!
Change in energy $Δ E$ must equal work done on the moving body $W$ .
Now, work is force over distance $W = F Δ s$
But we also know that force is mass times acceleration, thus $F = m a$ .
If you have a body moving under the influence of constant force $F$ over time $t$ , starting from the speed 0, it will have a speed $v = F t / m$ at the end. It’s easy to see that the average speed it travels will be $v / 2$ though and thus the distance travelled will be $Δ s = v t = \frac{F t^{2}}{2 m}$ .
Now, the kinetic energy equals work and thus $Δ E = F Δ s = \frac{1}{2} m (F t / m)^{2} = \frac{1}{2} m v^{2}$ .

Samuel Hapák 29 Dec 2023 16:37 UTC
2 points
in reply to: Marco Discendenti’s comment on: Boltzmann brain’s conditional probability
Surely. You just need to make some prior on the 3rd. Note, that the 3rd hypothesis is something along the lines of “there is some other model besides Boltzmann hypothesis or Boltzmann brain”, not a specific hypothesis. It can be big bang, god created the universe, or we live inside simulation. Whatever.

Now, you would have to assign unreasonably small prior to this for it not to end up many orders of magnitude more probable than either of Boltzmann Hypothesis or Brain.

Samuel Hapák 29 Dec 2023 15:06 UTC
7 points
on: Boltzmann brain’s conditional probability
I understand your post as trying to argue that Boltzmann hypothesis is more probable than the Boltzmann brain because our subjective experiences are consistent with physical laws.

If that’s the case, your conclusions are wrong. Boltzmann brain is still more probable in this scenario. The mistake you make is excluding the 3rd option that the reality we experience is objective for some other reason (a reason we might not understand yet).

Now, your post is a good argument in favor of 3rd option and against both Boltzmann brain and Boltzmann hypothesis.

Samuel Hapák 27 Dec 2023 19:39 UTC
9 points
6
on: In Defense of Epistemic Empathy
Thank you for writing this.

I always felt lots of empathy to all the people in my out-group^[1]. Yeah, they believe to a bunch of wrong ideas for dubious reasons. So? My in-group usually believes a bunch of right ideas for similarly dubious reasons! They have no moral high-ground to claim the truth. Often, the out-group has better ideas to believe what they do than my in-group despite being wrong about the end result.
I actually think that it’s worse when people are right for the wrong reasons than if they are wrong. In the latter case, there is at least a chance that reality will slap them into face eventually.
1. ^
  Out-group here is strongly topic dependent. Pretty much for every topic the in-group and out-group looks different to me.

Samuel Hapák 22 Dec 2023 22:34 UTC
3 points
1
in reply to: jefftk’s comment on: Pseudonymity and Accusations
I don’t think it’s much grey. It’s not the question of whether you are doing perfect job protecting your identity, but are you even trying?

Samuel Hapák 21 Dec 2023 21:59 UTC
10 points
8
on: Pseudonymity and Accusations
I would say that the norm should be:

— If someone is building pure online persona, it isn’t appropriate to dox them because of their online activities. There essentially is no added value for society in doing this. The person is using pseudonym to freely communicate their views and opinions while protecting their day-to-day life.

— Once anyone starts to bring real physical life into the conversation (such as your example) they are becoming a fair game. It’s them who linked their online presence to real life, they doxxed themselves.

I would say, if you want to stay anonymous, you should show at least some effort in trying to protect your identity.

Samuel Hapák 29 Nov 2023 21:08 UTC
3 points
0
on: Losing Metaphors: Zip and Paste
I would say that zip and unzip can be understood as an equivalent to rar and unrar, tar and untar. I wouldn’t say that it necessarily needs anyone imagining a bag being zipped. But, it might as well be the fact that English isn’t my first language.

Samuel Hapák 16 Nov 2023 15:08 UTC
4 points
2
on: Kids or No kids

If it seems weird to spend hours deliberating and negotiating over an Excel sheet with your partner, consider how weird it is not to do that—you are making a decision that will cost you hundreds of thousands of dollars and is binding for years; if you made this type of decisions at work without running any numbers, you’d be out of a job and likely in court pretty quickly.

I am making decisions worth hundreds of thousands of dollars without running any numbers pretty often at work.

They haven’t fired me yet.

Samuel Hapák 15 Nov 2023 23:51 UTC
2 points
1
in reply to: RamblinDash’s comment on: Redirecting one’s own taxes as an effective altruism method
Well, on the similarity/difference point, I would say that the line between legally rearranging one’s affairs and not paying what is owed is a very thin line. Government usually doesn’t like when you rearrange stuff to reduce your taxes and thus often the legal doctrine says that as long as your primary motivation in rearranging your affairs was lower tax it’s classified as a tax evasion and thus illegal.

On the morality point, I am not defending the deranged “the end justifies the means” principle. All I am saying is that many people don’t consider the power the government is exerting over them (eg the power to collect taxes) as legitimate and thus don’t see anything wrong with not paying the taxes.

Samuel Hapák 13 Nov 2023 21:22 UTC
3 points
4
in reply to: RamblinDash’s comment on: Redirecting one’s own taxes as an effective altruism method
Why?

Some people don’t believe in the moral imperative to pay taxes they legally owe.

Samuel Hapák 22 Oct 2023 21:36 UTC
1 point
0
in reply to: M. Y. Zuo’s comment on: How To Socialize With Psycho(logist)s
Well, these relationships have a very important characteristic which is that the younger catches up with the older quite quickly and often overcomes him/her. The asymmetry is often quite a temporary matter.

I would say that most visible is this on parent/child relationship. As the child reaches adulthood, he/she becomes more and more equal with the parent. I would claim that around 30 they are pretty much equals. And the relationships (at least from what I observed) become very symmetrical: parent brings up his/her problems as often as child. As the parent becomes older, the roles often reverse a lot. It’s the child that needs to help the aging parent to navigate the world.

Lastly, you mention ¹⁄₃ as somehow being a low factor. I don’t know what the true factor is but I would consider ¹⁄₃ to be quite a good ROI ;-)