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Mechanics and logic

  1. Jun 12, 2012 #1
    Hi everyone! I'm having a problem. I would really appreciate some answers. I'm thinking of changing to another major. :\

    I'm majoring in Industrial Eng., which has a lot of mechanical classes at my institute.

    I have a very logical mind, and I like to connect everything about a subject: from its fundamental ideas to its implications through deductive reasoning. But I'm failing to make that kind of logical connections with classical mechanics! I'm also very detail oriented, which is driving me crazy when I study mechanics!

    I have very high grades at everything including mechanics. But, despite my efforts to really understand in depth the mechanical concepts, I still feel like nothing about it really flows in my head. I can't create logical networks in my head, like I could in classes like programming, numerical mathematics and operations research.

    I find myself trying to explain some solid or fluid movement results thinking about the interactions at molecular level (keeping the classical laws, which I know aren't quite accurate, but at least they should explain more or less why it's plausible that some macroscopic events might happen), and I almost always fail!

    I feel very bad having a very intellectual/mental life and reaching nowhere when it comes to mechanics. I feel the most dumb person in the world when thinking about it, despite being one of the best students when it comes to grades.

    Is it normal to have this problem with classical mechanics, which should be easy but for me are very hard to connect logically, considering myself an intelligent person? Would it have to do with the fact that I am not a spacial thinker? Or am I really a dumb person? :(
    Last edited: Jun 12, 2012
  2. jcsd
  3. Jun 12, 2012 #2
    Industrial Engineering is more like Mechanical Engineering? Sorry, not trying to derail the thread, I believe you are doing what some call, "over thinking" it.
  4. Jun 12, 2012 #3
    No no. My industrial engineering major is very very similar to mechanical engineering. This is not usual, but in my institute industrial is more towards mechanics than management: we have technical design, materials, manufacturing processes, statics, dynamics, computer design, automation, solid mechanics, thermodynamics and heat, fluid mechanics, machine elements, mechanical project. We and mechanical students share a lot of same classes actually. I think I0m not "over thinking". Please reconsider. :P
    Last edited: Jun 12, 2012
  5. Jun 12, 2012 #4
    I'm not sure that I understand your concerns. Could you provide a specific example?
  6. Jun 13, 2012 #5


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    Some things are simply too complicated to intuitively come up with on your own, especially when it comes to dealing with non-idealized, real systems with all their quirks... as you need to in engineering. Think of mechanics of materials: Maybe some very clever people might have some up with the relationship between dislocations and plasticity on their own on purely theoretical ground by just thinking... but coming up with the Frank-Read source or the interaction between dislocation stacks and grain boundaries without first seeing such things in real systems? No way. And fluid mechanics, aerodynamics, mechanics of friction etc are not at all simpler (can you see the behavior of vortices and turbulence in the Navier-Stokes equations? I can't).

    In real systems, once you want to understand everything down to the molecular level, you are bound to run into countless problems, often caused by multiple qualitative effects with different signs interacting, or with behavior being dominated by rare events one cannot easily predict. Sometimes in hindsight everything turns out to be easily understandable, but sometimes it does not. Getting this kind of understanding and making it useful for applications is precisely the point of engineering. You cannot expect to know everything from the beginning, or to be able to find out everything on your own. You should keep on trying to explain everything for your self, but should not worry too much if this does not always work at this point. After all, you would not expect to instantly come up with all mathematical proofs out of nowhere, too, or would you?
  7. Jun 13, 2012 #6


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    There's nothing wrong or dumb about that sort of thinking. The only "problem" is that it's usualy called "physics", not "engineering".

    Maybe the root cause of your problem is you are majoring in the wrong subject. There are no limits that I've ever found to the level of thinking or insight you can apply to engineering, but at the end of the day you have to turn the thoughts into engineering, not something else.
  8. Jun 14, 2012 #7
    I just would like to know if some statements are empirical or if they are well supported by fundamental laws. I just can't connect things so I can enjoy this field (but I would accept that 80% of mechanical engineering is purely empirical, but I want to know what is, and most of the times books don't tell).

    I don't find interesting "puzzles" to solve, like I did in the few logic related courses I had. I have a big satisfaction when I make a kind of cause effect mental network of ideas/situations. I'm failing to do that with mechanics :\

    Should I change major?
  9. Jun 14, 2012 #8
    Well yes. In high school my favorite subject was physics (now in university I found another passion for algorithms). I love to understand things at the very root level!
    But I don't like the quantitative foundations of classical mechanics, maybe because I'm a bad spacial thinker and maybe because I'm a bit skeptical about continuum world (but that's another story :P).

    The reason I don't usually think about going to physics is because I think modern physics (and all the quantum world), although being very interesting at qualitative level, could drive me crazy at the quantitative level, because I hate when I can't find the logic in a subject, whether it is because of being hard or whether it doesn't make that much sense. I heard that quantum mechanics challenge all my lovely logic :P, at least now, I believe one day it won't.
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