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Cake day: August 1st, 2023

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  • Yes, there’s a bit of a myth around Bernoulli’s principle (faster moving fluids have lower pressure) and how much it matters for lift in plane wings. It came up in the conversation because I was trying to describe what air pressure is in general, and made an analogy to a pan flute (he plays flute in band).

    Disclaimer: I’m an aerospace engineer, but I do not claim to be an expert on topic.

    But for plane wings, the myth is really that the air above the wing moves faster because the curved surface is longer. That’s pretty much dead wrong, but is still in tons of textbooks. The air above the wing does move faster, but it’s because of a bunch of complicated physics that to be honest, I don’t really understand any more. I may have even been taught wrongly in college. But the result is that there is a velocity difference on a cambered wing even when it’s flat, and thus Bernoulli’s principle does apply, and there is a pressure difference giving you lift.

    But that speed difference is mostly important at cruising altitude, when the wings aren’t angled, and it’s positively correlated with airspeed, so the thrust matters way more. When you’re climbing, the angle matters more. The camber (curvature) of the wing, the airspeed, and the angle of attack all lead to that pressure difference, along with a few other things like circulation, which is also caused by a sharp edge at the back of the wing. But everything kind of works together to generate that pressure difference and hence the lift that can combat gravity. It’s actually pretty hard to try and dumb it down without saying things that aren’t wrong.



  • I think that’s also the problem today, albeit of a different sort. I had a friend who was very seriously into the “punch Nazis” meme on the internet a few years ago. But he would often talk to us about it and finding someone to punch. He sometimes said shit like “I could just go to the Republican national convention and start punching people.”

    If it floats your boat, punch Nazis. But don’t punch everybody you disagree with because “not supporting universal healthcare” is not being a Nazi.



  • Because people are rarely single issue voters. There are a few here and there, but given the dominance of the US’s two-party system, you often have to make a choice. If I imagine 2 candidates: one who is strongly pro-choice but overtly anti-gay, and another who is strongly pro-life but also pro-LGBTQ issues, that would actually be a pretty tough decision for me.

    As much as I want to hate Trump supporters, I can still sympathize with them. A lot are lifelong Republicans who are choosing between someone who will probably try to enact 90% of their personal beliefs but is an authoritarian crazy person, and someone who seems sane but disagrees with them on 90% of issues and will do everything to stymie the things they believe to be right. It’s not a simple choice.

    I’m ignoring third-parties here as a caveat, so apologies if that’s the crux of your question. But my opinion is that you should push for and vote for a new system while accepting that the rules are what they are now, and you have to strategize with the current situation.











  • We could avoid this entirely, but the idiot Congress LIKES it. I don’t think any other country has a debt ceiling like the US. Why? Well, because when another country’s government (legislature, dictator, voodoo shaman) authorizes spending on something, they also authorize paying for it.

    But in the US, Congress says (to the executive branch) you can only collect 50 bajillion in taxes, no more, no less. Also, you have to spend 55 bajillion on these programs, no more, no less. Then the president says, “uh, okay, but I’ll need to borrow 5 bajillion to do that because of math.” In reply, Congress stamps its collective foot like a toddler and says “NO NO NO YOU HAVE TO ASK US FIRST! Why are you drowning this poor country in debt you spendthrift!”