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Darren New <dne### [at] san rrcom> wrote:
> Is there any other field of endeavor where a phrase like
> """
> Like all of my examples it's one of those super-simple examples; small
> enough to be unreal, but hopefully enough for you to visualize what's going
> on without falling into the bog of a real example.
> """
> is common? Where people teach principles with overly-simplified and
> unrealistic bits because doing it for real is too obscure?
How about math? When was the last time you were in a math class where
they discussed a *real-world* example, rather than a simplified artificial
example?
I think this goes all the way from adding apples to calculating fourier
transforms.
--
- Warp
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scott wrote:
> It wasn't until University that we solved that one with
> deformation of the surfaces and roughness.
That sounds pretty awesome. We never got quite *that* far. I think our
experiments weren't so precise we had to worry about anything more funky
than the total rolling friction of the cars. We didn't calculate the
deformation of the track or anything like that.
Altho I do remember that at one time I knew how to calculate the speed of
light given the mass and charge of an electron, and why it worked that way.
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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Warp wrote:
> How about math? When was the last time you were in a math class where
> they discussed a *real-world* example, rather than a simplified artificial
> example?
Well, math isn't "real world", so I'm not entirely sure what you refer to.
Unless what you're saying is they don't teach real-world examples of
applying sufficient math to the real world to get real-world useful results?
I.e., they cover math that's too simple to be isomorphic to the real world
behavior of stuff? Stuff like (as your examples suggest) showing the fourier
transform, but not how it works on a real noisy and non-infinite sample?
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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Darren New wrote:
> Unless what you're saying is they don't teach real-world examples of
> applying sufficient math to the real world to get real-world useful
> results?
Speaking of which, I studied calculus for something like three years before
I did sufficiently "real" physics to say "Oh, so *that's* what integration
is for." So, yeah, I guess physics is another one of those. :)
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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Darren New <dne### [at] sanrrcom> wrote:
> Well, math isn't "real world", so I'm not entirely sure what you refer to.
Math is exactly as "real world" as programming. After all, there isn't
that much difference between the two.
You don't see "programs" in the real world. You can *express* some
real-world phenomena with a program, but so can you with math.
--
- Warp
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Warp wrote:
> You don't see "programs" in the real world. You can *express* some
> real-world phenomena with a program, but so can you with math.
I see what you mean, yes. And it makes sense, I think, in that the places
where you see oversimplification are similar in both cases. Passing
arguments doesn't get presented in over-simplified ways. Only techniques for
working on million-line programs gets oversimplified. So yeah, math is a
good one.
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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> That sounds pretty awesome. We never got quite *that* far. I think our
> experiments weren't so precise we had to worry about anything more funky
> than the total rolling friction of the cars.
Yeh that's fine for linear motion when you don't accelerate or brake too
hard, but when you are trying to calculate whether the front wheels or rear
wheels will start to skid first during a sharp corner you have to consider
how the tyre deforms. The simple model you can use is to assume the tyre
surface is like a paint brush - covered in bristles all pointing outwards at
rest, but they have some stiffness (so they can bend in all directions).
The key point then is that when you start to steer (or brake or accelerate)
the bristles in contact with the road will bend a certain way, and the ones
near the edge of the "contact patch" will actually slide across the road
because they have a very low vertical loading. As you
steer/brake/accelerate harder the % of bristles that are sliding across the
tarmac increase (in a positive feedback loop after a certain point) until
the whole tyre is skidding across the road.
> We didn't calculate the deformation of the track or anything like that.
For railway cars it's exactly the same situation, just that obviously steel
is more stiff than rubber, and the track deforms significantly as well.
> Altho I do remember that at one time I knew how to calculate the speed of
> light given the mass and charge of an electron, and why it worked that
> way.
I can't even figure out how a black hole manages to bend light when photons
have no mass :-(
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scott wrote:
> I can't even figure out how a black hole manages to bend light when
> photons have no mass :-(
Supposedly it's bending the space through which the light is traveling,
not the light itself.
--
Tim Cook
http://empyrean.freesitespace.net
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scott wrote:
> The key point then is that when you start to steer
That's cool, yes. I'm sure that people actually engineering cars or trains
go though all that sort of stuff. I don't imagine the teacher would have
assigned the problem if we needed to calculate that sort of thing. :-)
>> Altho I do remember that at one time I knew how to calculate the speed
>> of light given the mass and charge of an electron, and why it worked
>> that way.
>
> I can't even figure out how a black hole manages to bend light when
> photons have no mass :-(
They do have mass. They just don't have rest mass. Indeed, the color of the
photon tells you its mass. And, in theory, the photons are going in a
straight line, and it's only the spoon ^H^H^H^H^H space that's bent.
--
Darren New, San Diego CA, USA (PST)
There's no CD like OCD, there's no CD I knoooow!
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