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How should I start?

  1. Jun 26, 2011 #1
    Hi everyone.
    I wanted to start learning physics quite a long time ago, but I never knew how to start. The thing is that I am Romanian and we have a different school system, so it's quite an annoying thing to make the change.
    But, anyway, the point is that I would like to learn physics. Maybe this sounds too general, but I'm doing this for fun, so there is no rush at all :D I plan on understanding relativity and quantum physics. This may sound foolish, but I do understand that this kind information can't be learned in one month or something, but in years of study.
    The thing is that I don't know where to start, and I don't actually know anything from school. I mean, I know some things, but I never actually enjoyed physics in school (one of my basic principles is that schools are bad). So, I don't quite know where to start. I guess basic Newtonian mechanics would be a nice beginning.
    So, can you, please, help me with some book recommendations, and some sort of topics (in order) that I should cover?And, considering that maths is the building block of physics, some math topics that I should cover would be great. I mean, I would want some prerequisites for special relativity (and maybe general, but it kind of scares me), or quantum physics.

    And please, no angry replies, I know that you can't just learn this things over the night, I just set some goals that I hope to accomplish.
     
  2. jcsd
  3. Jun 26, 2011 #2
    You should start out rebuilding your foundation in math. My first recommendation is to do all off the exercises (until you're comfortable with them) on khanacademy.org

    From there you can move to an introductory physics textbook; I recommend University Physics by Sears and Zemansky.

    From there you'll have a good foundation in basic physics and basica math. You'll want to extend your knowledge in calculus and linear algebra. Most people here will recommend Spivak's Calculus. I've used 2 linear algebra textbooks over the last year (different courses) and didn't really enjoy either of them so I don't want to recommend something there.

    Once you've built up a solid foundation in Calculus and Linear Algebra you can move on to classical mechanics (which will include special relativity). If you want a real challenge and think you're up to it you can learn out of Landau and Lifgarbagez "Mechanics" book.

    Once you're studied up to there (this will honestly take maybe 3 years to master) you will have a good idea of what kind of math you're missing in order to tackle the harder problems in general relativity and quantum physics. But only after you have mastered the basic math and physics can you move to the harder material. For General Relativity calculus on manifolds and Riemannian geometry is important. For Quantum physics abstract linear algebra is important.

    Check out this link for a more thorough description of everything you need to study:

    http://www.staff.science.uu.nl/~hooft101/theorist.html
     
  4. Jun 26, 2011 #3
    To the OP, why not pursue higher education or at least some form of education with all the physics you're going to study? Considering your interest and how genuine it sounds, you can really go far and learn a lot. You could really be a blessing in some field.

    My two cents
     
  5. Jun 26, 2011 #4
    @Clever-Name Thanks for the reply :D I actually did start with math, and I plan on doing Calculus 1 and 2 first, and then I plan on going deeper with maths(math is a nice topic too).Also, I found this on the forum https://www.physicsforums.com/showthread.php?t=61886

    @Edin_Dzeko I can say there was quite a little bit and I didn't pass the year, so yeah, I'm not the school guy :D Professors are nice, and some of them really do their job great, but the educational system in my country is way more rigid than in the US, so it doesn't deserve to bother. And about the job, I'm more of the computer guy (more into algorithms, that got me into maths that somehow got me into physics ^.^ ), I just do this because I like to explain stuff to myself and not just get pre-thinked ideas and memorize them :D
     
  6. Jun 26, 2011 #5
    If you want to understand physics, the best place to start is Newtonian Mechanics regardless of what you want to focus in.

    If you want to understand Newtonian Mechanics, you will need at least basic calculus. I learned machanics out of Kleppner and Kolenkow (it is an advanced text though, there is even some parts that use mulitvariable calculus in the book. The book also covers the fundamentals of special relativity) and most people I know learned Calculus out of Stuart (it covers calculus I, II, and III).

    Some Electromagnetism may be helpful with special relativity but it definitely isn't necessary unless you want to understand more advance topics (such as why moving charges give off a magnetic field. That may have been the most mind blowing things I've learned yet). If you choose to learn some, you will need to learn calculus up to vector calculus.

    After calculus, differential equations and linear algebra is a must. You see a lot of differential equations in more advanced mechanics and plenty of linear algebra in more advanced special relativity.

    For quantum mechanics, you will need to know PDE's pretty well and advanced linear algebra (instead of column vectors you will deal with functions that behave like vectors. Instead of matrices you will deal with general operators). Probability is also pretty helpful for quantum mechanics but only basics are really necessary: how to find expected values, standard deviations, basic probability theorems. Very few actual systems can be solved exactly in quantum mechanics, most books you come across will spend a lot of time using approximations to get answers that are "good enough". If you really want to understand quantum mechanics, make sure you are good with understanding why the approximations are made and why they work.

    I think general relativity has by far has the most sophisticated math requirement. I don't know much about it, just that the subject you will need to go over is differential geometry. At my school real analysis is a prerequisite but that may be because it a rigorous study of manifolds and the like.
     
  7. Jun 26, 2011 #6
    yes it's my question too "how should i start ?"
     
  8. Jun 26, 2011 #7
    If you are looking for a math textbook for after you study basic calculus, there is a book by Mary Boas called "Mathematical Methods in the Physical Sciences" that covers the more advanced math topics necessary for undergraduate physics courses. General Relativity is more of a graduate topic though and the book lacks a chapter on differential geometry (it includes a chapter on tensor analysis but I do not know how far that would get you. I don't know squat about General Relativity).

    I also forgot to mention earlier that knowledge of complex numbers is needed for quantum mechanics.
     
  9. Jul 21, 2011 #8
    So basically you are starting from scratch, and you want to end up with the equivalent of a BS in Physics, and you are prepared to study for years to achieve that?

    If all that is correct, then the solution is obvious: follow an undergraduate physics curriculum. Just look at the websites of the physics departments of any of hundreds of universities, and you will see the classes they require. Many will have the entire four years all laid out. And many, like MIT's OCW site, have complete lecture notes, solved homework and exams, and even video lectures. Buy used older editions of the textbooks for about a tenth of what a new one would cost, and follow along at your own pace.

    For best long-term results, you should probably do a semester's worth of calculus before you start on the physics classes. If you're not ready for calculus, then start with precalculus. Or basic algebra and trig, if you have to.

    It won't be easy, but it should be very rewarding. Best of luck to you.
     
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