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Getting good at classical mechanics?

  1. Apr 9, 2014 #1
    Hi all,

    I'm a first year undergrad and I'm currently struggling with Physics. I aced high school physics (A-levels) but for my first class test at uni, I got a 50% and now I'm not sure if I'll be able to make this to 90%+ during the second class test (in exactly a month from now).

    We are doing matter and interactions and everything involves vectors now. The book I'm using is Matter and Interactions by Chabay and I don't know if this book is good. We covered 6 chapters so far and I decided that I'll restart from the beginning of the book move on from there. Next week chapter 7 starts. I'm freaking out.

    My problem is that I don't like this book but we are using it extensively in class. The lectures are totally based on it. There are no answers for the questions, and I'm now sure how I'll know if I'm on the right track or not.

    Are there any books for classical mechanics solely with problems? And which has an answer book as well? I really want to get as much practice as I can and ace Physics again. I'm totally doubting my Physics these days :(

    Can you guys suggest some books which I can use to learn all these? I need a book which makes use of vectors, I guess this transition to vectors is what got me the poor result to begin with, but I'm getting the grasp of it now. However, I don't like the approach of the book.

    I would really appreciate if you guys could give me some nice books to learn Physics and I would really appreciate some revision tips. And, do you people think, it will be possible to get the 90%? The lecturer says that the first test reflects the final grade for the year.

    I need some serious replies please. I'm quite lost these days.

  2. jcsd
  3. Apr 9, 2014 #2
    You can get 100%. But don't expect it to be easy. Don't listen to what the lecturer says. To be honest the best one out there, which worked for me at least was Keith Symon's Mechanics(really good for start.... I had difficulty picking up vectors when I got into college too... all I can say is that only time and practice gets you to understanding them. Also try to use your brain and imagination when working with vectors....Your imagination and geometrical view of how vectors add , multiply, all that is really what gets your brain to understand them. And then there's the math part (integrating vectors, del operator, circulation and all that)which for a physics student doesn't need to be really vast. You will better understand the advanced and complex vector math later with the help of the physics.
    There aren't many good books on the basics of vectors that I can think of and the math ones are just too much for your needs. Only one I can think of is Tai Chow's Mathematical Methods for Physicists. Almost everything you need to know about vectors is in there.
  4. Apr 9, 2014 #3
    First, I want to applaud your efforts to do better in physics (especially mechanics). You are going to be much better off attending to these difficulties now rather than one month from now after your second test.
    Second, although your test was 50%, you make no mention of a class average, and statistics for the first test. Perhaps 50% is not bad. The mean (average) for my first test in college physics was about 50%. I have even heard of some professors who geared their test so 50% is a solid B. I remember talking to my recitation instructor about a 50% score and he looked at this in relation to the other scores, and just said, "What are you worried about?". (However, I left the course with a B-, probably due to worsening performance.)

    Because the professor may design the test to "test" the students, a 90% score may actually be impractical, and out of reach. I had a math professor design a final with 435 total points. Anything above 180 was an A. The rest of the test was an assortment of problems with varying degrees of difficulty and variety with the intention that some problem could be tackled by anybody. Even full knowledge would not allow one to complete the test in 3-4 hours. (The paper would probably catch fire with the furious writing).

    It sounds like you have already checked with your lecturer as to how you are doing. This is good too.

    Are there good books on classical mechanics that focus solely on problems?

    Yes, David Morin's, Introduction to Classical Mechanics is highly regarded in physics forums and focusses almost exclusively on problems. I do not recommend it as a first text however. The problems are too difficult. Resnick and Halliday, (RH) Physics for Scientists and Engineers usually provides answers to odd-number questions.

    Answer books are available to RH, but this is not necessarily what you want. A little struggling in learning mechanics is good for you. Your recitation instructor, or professor or lecturer should be pleased to help you beyond these struggles, especially if (s)he sees a concerted effort. I have seen instructors ( or ultimately the graders) move a grade up a notch in borderline cases, when they see an effort.

    You mention you do not like Chabay. I am not totally comfortable with it either. I find what most texts call Newton's 2nd law, Chabay calls it something else. The author's motivation to present the material in a fresh manner is a good one. I prefer the traditional treatment in RH, or Giancoli, or Tipler (I feel best is still RH).

    You do not have to worry much that you need a text emphasizing vectors. Any physics (mechanics) text written in the last 150 years will do that. It is reassuring that you feel you are getting a grasp of vectors now.
    Be careful that your diagnosis that vectors were the problem is accurate. (It could be that alone). It may also turn out your conceptions on energy or other physical principles were wrong.

    This is already a long post and I may get back with specific recommendations later. Best of Luck.
  5. Apr 9, 2014 #4
    Symon's Mechanics book is excellent at the junior/senior level but I think it is difficult as a introductory physics book. It may work for you, but Symon will treat mechanics at a level that is likely to be far above your tests, if your instructor is using Chabay.
    Last edited by a moderator: Apr 10, 2014
  6. Apr 9, 2014 #5
    I would like to reemphasise a point the poster above made
    I am in uni too and from the UK too; the difference between what is a "good" score at uni and at school is vast.

    In school you may be used to getting over 90% all the time but at uni hardly any one will do that, if anybody. In the UK 70% and over is a "first" i.e. the best grade there is for a degree. 60-69% is a 2:1 grade(upper second class), between 50 and 59% is a 2:2 (Lowe second class) and 40-49% is a pass (third class).
    Last edited: Apr 9, 2014
  7. Apr 9, 2014 #6
    Thanks guys I'll check these books out. I'm not looking for a book specifically on vectors(although it could help in my applied math class. Ironically, I got 93% in vectors for applied maths where we did all sort of stuff from addition of vectors to showing why we are not at the center of the universe). I'm more keen on a Physics book which uses vectors in their topics. I'll look into Symon and see if it's good to start with, but I look forward to more suggestions.

    @mpresic - I don't know the class average exactly but I have the statistics. 85 students, 19 got 50-59, and 53 got above 60%. Now 27 got above 80% with 11 above 90%. 3 or 4 got 99.9%(not 100%, wonder why).

    Based on these, I'm sure it's possible to get above 90%, but will it be possible for me, within a month? I'm trying to catch up before the end of this week, that means 6 chapters at 1 per day(Covered 2 already, though didn't do the questions except for some basic one in the book). That's why I'm looking for a good book with problems that have answers. I don't need the worked solution. Just some answers where I can say: "Okay, I'm on the right track". Chabay is loaded with errors(although there is an errata) but there are no answers. I can't do 10 questions or even 1 and not knowing how I am doing.

    The physics department is giving one more tutorial for guys who got below 60%. I feel bad in some way, to land here(because I was good in Physics) but, I guess, on the other hand I could exploit this to my advantage. However, I can't wait for a week to get my questions answered. I need to know the stuff way before hand.
  8. Apr 9, 2014 #7
    I'm not actually from UK but I did A-levels as international since it's part of my high school curriculum. At my university, here it's 75% and above for A(or "first"). It's mostly module based for now in my case.
    Last edited: Apr 10, 2014
  9. Apr 9, 2014 #8
    You shouldn't feel bad. Think about it, its just stats. If your doing a physics degree, then everyone on your course would have been good at physics at school, that's why they are there; you've done good to get where you are, not everyone could have got over 60% otherwise it would have been a poorly constructed test.

    Edit: sorry I posted this before seeing your latest reply, but you get my point :)
  10. Apr 10, 2014 #9
    I get your point. I hope it will be possible to make my marks to 90%+ next time.
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