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We(by which I mean a person who knows how to ride a bike) do understand how to ride a bike. The problem in communicating that is a riding a bike is a skilled ac

by somat 2y ago

We(by which I mean a person who knows how to ride a bike) do understand how to ride a bike. The problem in communicating that is a riding a bike is a skilled act. that is you cant get good at riding a bike by reading about it, and it is very hard to describe a well trained skill, it boils down to "practice a lot" which makes nobody happy.

adastra22 2y ago
One of the reasons you can’t get good at riding a bike by reading about it is that we literally don’t understand the mechanics of bike riding. It’s a currently unsolved problem in physics. Google it if you do t believe me! So I get what you’re saying, but it is maybe not the optimal example.
- moi2388 2y ago
  It’s not. Google harder.
- rcxdude 2y ago
  It's not unsolved per se, just a complex topic that resists simple explanations. (see also: what causes lift in an airfoil)
  - adastra22 2y ago
    Sibling comment to yours points to a relatively recent (this century) article with a mostly complete theoretical model for bike self-stability. There are other theories though, some more or less developed than others. It turns out to be a fiendishly hard control-theory problem, and at least one aspect is chaotic. Which theory is correct has not, to my knowledge, been definitively determined by experiment. Until it is, I think it is fair to say that it is unsolved. Unlike lift, which is very well understood but often poorly explained.
  - Syonyk 2y ago
    > (see also: what causes lift in an airfoil) That's easy! It pushes air down, and the reaction force is what we call lift! ... now, why it pushes air down... there be many computational fluid dynamics PhDs... though "angle of attack" covers a lot, and the rest is just efficiency tweaks. Good question for teachers who insist it's the Bernoulli Principle: "But my paper airplane has flat wings and flies just fine!" toss across classroom
- hattar 2y ago
  https://royalsocietypublishing.org/doi/10.1098/rspa.2007.1857 https://royalsocietypublishing.org/doi/10.1098/rspa.2007.185...
  - gsf_emergency_2 2y ago
    MATLAB Code from the authors: (There's no rider however) http://ruina.tam.cornell.edu/research/topics/bicycle_mechanics/JBike6_web_folder/ http://ruina.tam.cornell.edu/research/topics/bicycle_mechani...
  - jorvi 2y ago
    > This conservative non-holonomic system has a seven-dimensional accessible configuration space and three velocity degrees of freedom parametrized by rates of frame lean, steer angle and rear wheel rotation. I always adore the split between how my brain does things instinctually, but making it arbitrary completely demolishes the 'natural' flow of it. Same with complex ball throwing / bouncing trajectory calculations. It also immediately makes me angry about how we teach math. When you learn about powers (squares, cubes, roots, etc), these things are just written out as arbitrary concepts instead of displaying them geometrically. Hell, when I was first taught the Pythagorean theorem, it was just explained by drawing a triangle with A² + B² = C², without also drawing out the related squares of each side. Immediately doing that would instill so much more intuition into the math. In general, mathematical concepts gain so much clarity by doing them geometrically.
    - necovek 2y ago
      Sounds like a problem with your early math tutors: especially with geometry, all the examples you bring up have been taught with "what it means". I mean, squares and cubes are just multiplication by the same factor: I distinctly remember even trapezoid surfaces, pyramid volumes being demonstrated by chopping and piecing parts together.
      - mlyle 2y ago
        In the US especially, too many programs have an insistence that doing things with symbols and doing things with shapes and solids are completely different things and don't relate the two.
- transcriptase 2y ago
  Even if we could perfectly and accurately explain the mechanics and mathematical representations of riding a bike, it would still be useless knowledge even to the few people capable of understanding it in terms of utility in riding one.

by somat 2y ago

adastra22 2y ago

One of the reasons you can’t get good at riding a bike by reading about it is that we literally don’t understand the mechanics of bike riding. It’s a currently unsolved problem in physics. Google it if you do t believe me! So I get what you’re saying, but it is maybe not the optimal example.

moi2388 2y ago
It’s not. Google harder.
rcxdude 2y ago
It's not unsolved per se, just a complex topic that resists simple explanations. (see also: what causes lift in an airfoil)
- adastra22 2y ago
  Sibling comment to yours points to a relatively recent (this century) article with a mostly complete theoretical model for bike self-stability. There are other theories though, some more or less developed than others. It turns out to be a fiendishly hard control-theory problem, and at least one aspect is chaotic. Which theory is correct has not, to my knowledge, been definitively determined by experiment. Until it is, I think it is fair to say that it is unsolved. Unlike lift, which is very well understood but often poorly explained.
- Syonyk 2y ago
  > (see also: what causes lift in an airfoil) That's easy! It pushes air down, and the reaction force is what we call lift! ... now, why it pushes air down... there be many computational fluid dynamics PhDs... though "angle of attack" covers a lot, and the rest is just efficiency tweaks. Good question for teachers who insist it's the Bernoulli Principle: "But my paper airplane has flat wings and flies just fine!" toss across classroom
hattar 2y ago
https://royalsocietypublishing.org/doi/10.1098/rspa.2007.1857 https://royalsocietypublishing.org/doi/10.1098/rspa.2007.185...
- gsf_emergency_2 2y ago
  MATLAB Code from the authors: (There's no rider however) http://ruina.tam.cornell.edu/research/topics/bicycle_mechanics/JBike6_web_folder/ http://ruina.tam.cornell.edu/research/topics/bicycle_mechani...
- jorvi 2y ago
  > This conservative non-holonomic system has a seven-dimensional accessible configuration space and three velocity degrees of freedom parametrized by rates of frame lean, steer angle and rear wheel rotation. I always adore the split between how my brain does things instinctually, but making it arbitrary completely demolishes the 'natural' flow of it. Same with complex ball throwing / bouncing trajectory calculations. It also immediately makes me angry about how we teach math. When you learn about powers (squares, cubes, roots, etc), these things are just written out as arbitrary concepts instead of displaying them geometrically. Hell, when I was first taught the Pythagorean theorem, it was just explained by drawing a triangle with A² + B² = C², without also drawing out the related squares of each side. Immediately doing that would instill so much more intuition into the math. In general, mathematical concepts gain so much clarity by doing them geometrically.
  - necovek 2y ago
    Sounds like a problem with your early math tutors: especially with geometry, all the examples you bring up have been taught with "what it means". I mean, squares and cubes are just multiplication by the same factor: I distinctly remember even trapezoid surfaces, pyramid volumes being demonstrated by chopping and piecing parts together.
    - mlyle 2y ago
      In the US especially, too many programs have an insistence that doing things with symbols and doing things with shapes and solids are completely different things and don't relate the two.
transcriptase 2y ago
Even if we could perfectly and accurately explain the mechanics and mathematical representations of riding a bike, it would still be useless knowledge even to the few people capable of understanding it in terms of utility in riding one.