• 24 Posts
  • 61 Comments
Joined 4 months ago
cake
Cake day: April 4th, 2025

help-circle

  • The thing is: You are using velocities v1, v2 which are relative to Earth. But none of the two vehicles collide with Earth - they collide with each other, thus the thing that matters is their relative speed, thus the difference of their velocities relative to Earth.

    (That’s also why the speed at which both Earth, the car, and the motorized bike move around the sun does not matter - relative speed is all what matters).

    The other thing is that a human colliding with an object of several tons weight with a speed of, say, 36 km/h is not “elastic”. 36 km/h is 10 meter per second, which is equal to about one second of free fall (accelerating with a= 9.81 meter per square second to the ground), which is equivalent to a fall height of h = a/2 * s ^2 or 5 meters.

    Somebody falling from 5 meters hight on hard concrete ground will not bounce up but will likely have some broken bones, or a broken skull. What happens is that all parts of thier body is decelerated to a speed of zero within a distance of one or two centimeters, which involves massive forces that easily break bones.

    And a speed of 14 m/s, or 54 km/h corresponds to a fall of ten meters depth - almost certainly lethal if hitting a two-ton concrete block.





  • Some of the UI isn’t open, otherwise it is Qt / Wayland / pyside with stsndard pkcon / rpm package manager and I program mine in Guile.

    And the UI isn’t the serious issue. The serious issue is propietary firmware which prevents you from really running Android / whatever on a vendor phone and also that a phone does not have one but around five different processors and only the “OS” one can be controlled by your own software. An Intel Pocket PC is far better in that regard, except that it won’t work as a telephone.

















  • Yeah, the issue isn’t the light motorcycles/mopeds/etc.

    A thing which has a motor and where the human delivers less than 30% of the power at max speed is a light motorcycle. The reason for that is with more power you need a heavier battery and a much heavier frame with better brakes. You need a solid helmet which again makes it impractical to pedal at power because it becomes hot. At 40 km/h, it becomes to chill in the winter and at 45 km/h or so, you really need protective clothing because otherwise in a fall, the asfalt will strip your skin off. At that point it is very clearly becoming a motorcycle. You have lost thr technical sweet spot of a bicycle at that point. There have been many attempts to blur that line (guess what the name “Mofa” comes from or “Moped” or why these things have pedals which nobody uses).

    And we have motor-powered bikes since a long time - over 75 years -, and regulations have evolved out of need. Traditinally, the motor was a combustion engine - but that’s the only difference and it is totally irrelevant for traffic safety.