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Cake day: June 17th, 2023

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  • To drive a car, a driver must:

    • accelerate
    • maintain speed
    • slow for changing road conditions
    • make turns
    • maintain lane position
    • change lanes
    • brake for obstacles
    • be aware of surrounding cars
    • read road signs and respond
    • navigate roads to reach a destination

    Cruise control can:

    • accelerate at the driver’s input
    • maintain speed
    • slow at the driver’s input

    Autopilot can:

    • accelerate
    • maintain speed
    • slow for changing road conditions
    • make turns
    • maintain lane position
    • change lanes
    • brake for obstacles
    • be aware of surrounding cars
    • read road signs and respond
    • navigate roads to reach a destination

    Which one sounds like it drives the car on its own? Which one is clearly misunderstood by the average driver due to a reference to a feature in an industry experienced by very few people by comparison?


  • Does a lower frequency signal travel the same speed? 1hz? I suppose it would be the same because the tether would have immense mass over it’s length. So even though I’m picturing an impractically long tether moving as one solid length to tap slow morse code, the mass would be unfathomably high and therefore inducing significant stretch. That’s without getting into vibration kinetic energy being lost to heat along the way

    I’m obviously not genuinely proposing this. It’s just a brain exercise.











  • so an engine can lift a car

    Force = pressure x area

    It’s not that big of a feat. Using the very low estimate of 2.5psi from another comment about exhaust pressure, that means it can sustain 2.5 pounds(force) per square inch. To lift half a 5000lb suv the force needed would be 2500lbs. Rearrange the equation to [area = force/pressure] and it becomes [area = 2500lbs/2.5 lbs per square inch] so 1,000 square inches. Divide by 144square inches per square foot (12x12) and you get 6.94 square feet gives you 2500lbs of force from 2.5psi. Then to find that area from a circle, divide by pi and square root the result (rearranging area=pi*r^2 ) and you find that 2.5psi will lift the side of an SUV with a little less than a 3 foot diameter circle. That’s about the size of the lift bags I’ve seen.

    And all that while I’m thinking 2.5psi sounds low. Regardless, I doubt an exhaust system would handle anything close to tire pressure before popping off fittings. Plus mufflers have weep holes and fittings tend to leak anyway. They rely on the direction and speed of exhaust gas a fair amount.



  • Funny you mention motorcycles with gear-driven cams as being exotic. Generally correct, but I happen to own one of the cheapest out there: the Honda VFR. I sought out mine for being the last with the gears before going to a normal drive in 02. It’s a glorious sound.

    Anyway, that’s true too, helical gear will need a beefy housing to resist that axial load. That’s more weight. A pair of helicals fastened together could help bring down cost, probably, compared to herringbone, but that’s added complexity. I can’t claim the tech is marketing wank but the video absolutely is


  • Do you wear jewelry? Do you have a nice watch that tells time just as well as a casio? Does your car feature upgraded wheels or upcharged paint? Have you paid more for fancy curtains when basic ones do the same job? Have you repainted a room just because you wanted a different color? Art, collectibles, novelties? Video game cosmetics are valuable to anyone who wants to express themselves the same as any other real life cosmetic. It can be especially important to young people who don’t have other avenues.

    That being said, fortnite is predatory as fuck and is one of the worst offenders for addictive design, FOMO engineering, and maximizing DLC purchases. It’s what the annual sports games wish they could do. It’s what CoD started to do. It’s fueled by social media and by glimpses of random players in each match with the latest skins.