Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Ask HN: How to self-study physics?

news.ycombinator.com

Post reply on HN
Print view View original

151–160 of 194 posts

Re: Ask HN: How to self-study physics?

#151

Post by selimthegrim »

antognini wrote: post #143

My personal recommendations for an undergraduate course in physics (based in large part off of my own undergrad curriculum): Foundations: 1. Newtonian Mechanics by A.P. French ( https://archive.org/details/NewtonianMechanics/mode/2up ). This will give you a good foundation for what is to come. 2. Spacetime Physics by Taylor & Wheeler --- first edition if you can find it! It is much, much better than the second! Speci…

I was going to say I thought I recognized these books! Just a note that the first edition of Kittel (part of the Berkeley physics series too) is arguably _better_ than K&K. The latter has one or two slightly more zeitgeisty problems.

Re: Ask HN: How to self-study physics?

#152

Post by mindcrime »

abdullahkhalids wrote: post #149
AnthonBerg wrote: post #111

Earlier quoted context omitted.

We all learn differently. Please don't deal in pedagogical certainties that may close doors unventured. Feynman's lectures were crucially eye-opening for me and many others.

I disagree with you. I teach physics. Everyone interested in physics should read the Feynman lectures, but they are neither sufficient or necessary to understand physics. They are merely oomph on top of already good understanding. Let's imagine physics=boxing. No amount of reading boxing books, or watching boxing videos is going to teach you any boxing. To learn boxing you have to throw 10,000 punches. To learn physi…

Let's imagine physics=boxing. No amount of reading boxing books, or watching boxing videos is going to teach you any boxing. To learn boxing you have to throw 10,000 punches. To learn physics, you need to solve 1000s of questions.

I'm not sure that this is a very good analogy. You can buy a heavy bag, and go out in your garage and throw 10000 punches - with no instruction - and still not know how to throw a proper punch. OTOH, you can watch a few videos, learn some technique, and then go refine it by throwing the 10000 punches in the gym, and be a lot better off. Of course, it still won't be as good as hands-on training from a proper trainer, but my point is that you need both in the boxing case.

For physics... eh, I dunno. My original plan for college was to major in physics, and then I discovered computers, and physics went (mostly) out the door and in the rear-view mirror.

Re: Ask HN: How to self-study physics?

#153

Post by ubercow13 »

ukj wrote: post #113
andrepd wrote: post #100

Earlier quoted context omitted.

>The observer effect in physics can be trivially expressed and evaluated as a mutating getter in any programming language. >It cannot be expressed in any Mathematical grammar. What on earth are you trying to say...? There is a whole mathematical treatment of quantum mechanics, measurement effect included (several treatments). More to the point, any algorithm can be formalised in e.g. a Turing machine, or any other eq…

>Any algorithm can be formalised in e.g. a Turing machine, or any other equivalent universal model of computation Quoting http://math.andrej.com/2006/03/27/sometimes-all-functions-ar... >>The lesson is for those “experts” who “know” that all reasonable models of computation are equivalent to Turing machines. This is true if one looks just at functions from N toN. However, at higher types, such as the type of our func…

What is special about a mutating getter? It operates on the state of the object S and outputs a new state S' and some value x. Some programming languages allow you to write 'functions' without explicitly passing all input state into the function, but does that imply anything fundamental or interesting about mathematics or computation? Is that anything more than a type of syntactic sugar?

Re: Ask HN: How to self-study physics?

#154

Post by ukj »

diegoperini wrote: post #144
ukj wrote: post #113

Earlier quoted context omitted.

>Any algorithm can be formalised in e.g. a Turing machine, or any other equivalent universal model of computation Quoting http://math.andrej.com/2006/03/27/sometimes-all-functions-ar... >>The lesson is for those “experts” who “know” that all reasonable models of computation are equivalent to Turing machines. This is true if one looks just at functions from N toN. However, at higher types, such as the type of our func…

Mutating getter? Sounds like a generator function that yields. Or a pseudo random number generator implemented with a monad (WorldState, Value). Or any tail-recursive non-void function that carry state without loss? I'm definitely not an expert but aren't irrational numbers are the best examples to show that these types of constructs already exist in math? You can't calculate them in finite amount of time. You use an…

Assume that it is a black box to you, even though it is a white box to me.

Every time you call read() on it - you get a different result. It has side-effects.

This violates the “purity” of Mathematics.

Re: Ask HN: How to self-study physics?

#155

Post by gaze »

andrepd wrote: post #100
ukj wrote: post #88

Earlier quoted context omitted.

I am to really glad to hear commentary like this coming from physicists. (read: glad to see others siding with my biases). Ceteris paribus there is one significant distinction between Mathematics and Computer Science: state. The Mathematical Universe is immutable/stateless/timeless. The Computational Universe is mutable/stateful/time-bound. The observer effect in physics can be trivially expressed and evaluated as a…

>The observer effect in physics can be trivially expressed and evaluated as a mutating getter in any programming language. >It cannot be expressed in any Mathematical grammar. What on earth are you trying to say...? There is a whole mathematical treatment of quantum mechanics, measurement effect included (several treatments). More to the point, any algorithm can be formalised in e.g. a Turing machine, or any other eq…

it's like... kinda true that the observer effect can be expressed as a mutating getter... but that isn't useful. The idea that it can't be expressed is really ignorant.

Re: Ask HN: How to self-study physics?

#156

Post by neutronicus »

propter_hoc wrote: post #126
scottlocklin wrote: post #74

For the love of God, don't use Feynman lectures to learn physics. That's something you read after you know physics, for relaxation and conceptual stuff. Resnick & Halliday is a much better freshman/sophomore book. Susskind's "theoretical minimum" is actually pretty good. http://theoreticalminimum.com/courses Fowler gives a pretty conventional undergraduate physics curriculum (adding Feynman in there somehow). If it w…

I can't believe I am reading a recommendation that someone with little background in E&M self-studies with Jackson. That book is incredibly difficult even with a great graduate-level professor.

It all depends on your background in PDEs. I think the undergrad physics curriculum is pretty weak relative to some engineering disciplines here and Jackson is what really exposes this.

Coming from Nuclear Engineering I thought it was fine.

Re: Ask HN: How to self-study physics?

#157

Post by madhadron »

scottlocklin wrote: post #133
propter_hoc wrote: post #126

Earlier quoted context omitted.

I can't believe I am reading a recommendation that someone with little background in E&M self-studies with Jackson. That book is incredibly difficult even with a great graduate-level professor.

The problems from undergrad (I think we used Purcell) were virtually identical. Jackson's book had problems which were more algebraically/computationally difficult, but otherwise; it was basically the same thing. It's a well written classic; no reason to use the book with slightly wimpier problems. He asked me how to learn physics; not how to learn some wimpy undergrad physics which doesn't give you the big picture.…

My graduate E&M course was actually taught out of Schwinger, which I thought was quite nice. I would never recommend it as a first run through E&M.

Jackson's problems are more technically difficult than, say, Purcell's, but how much of that difficulty actually helps with understanding E&M?

Re: Ask HN: How to self-study physics?

#158

Post by davidivadavid »

ukj wrote: post #150
Koshkin wrote: post #140

Earlier quoted context omitted.

https://gabrielsw.blogspot.com/2012/04/purely-functional-tur...

Yeah! So you know that read:T call that you have implemented in Scala? You know that it could produce a different result on consecutive calls, right? Because the notion of a mutex/lock doesn’t exist in Math. Mathematics doesn’t allow that, because it is not a “pure function”. https://en.wikipedia.org/wiki/Pure_function Non-determinism is the norm in distributed systems. e.g any networked Turing machine.

You seem to imply that there's no mathematical model/theory of non-deterministic/distributed systems. Surely you don't believe that?

Re: Ask HN: How to self-study physics?

#159

Post by psalminen »

rguzman wrote: post #92
scottlocklin wrote: post #74

For the love of God, don't use Feynman lectures to learn physics. That's something you read after you know physics, for relaxation and conceptual stuff. Resnick & Halliday is a much better freshman/sophomore book. Susskind's "theoretical minimum" is actually pretty good. http://theoreticalminimum.com/courses Fowler gives a pretty conventional undergraduate physics curriculum (adding Feynman in there somehow). If it w…

context: former theoretical physics grad student, dropped out ABD to start a company. this comment is right on the money on several fronts: - the Feynman lectures are great after you already understand some of the mechanics of "doing" physics and have some other exposure to the topics, Halliday & Resnick is a better place to start on any one topic - with infinite time, i'd always follow the approach of learning the m…

Second Griffiths books, I used both his E&M and QM books in undergrad. His voice is excellent.

Re: Ask HN: How to self-study physics?

#160

Post by diegoperini »

ukj wrote: post #154
diegoperini wrote: post #144

Earlier quoted context omitted.

Mutating getter? Sounds like a generator function that yields. Or a pseudo random number generator implemented with a monad (WorldState, Value). Or any tail-recursive non-void function that carry state without loss? I'm definitely not an expert but aren't irrational numbers are the best examples to show that these types of constructs already exist in math? You can't calculate them in finite amount of time. You use an…

Assume that it is a black box to you, even though it is a white box to me. Every time you call read() on it - you get a different result. It has side-effects. This violates the “purity” of Mathematics.

I just explained three different models to represent side-effects without leaving the purity. I'm not sure if you are trolling, throwing random big words or simply have a really misguided impression about how computer science connects with math.
Post reply on HN