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Physics is just too hard.

  1. Oct 31, 2011 #1
    I still can't even start a problem after hours of studying the subject. I feel like an idiot, or that I'm just trying to do something that I can't do.

    The book that we use, nothing helps in it to solve the problems. All they give is the basic form of the equations. Doesn't tell you anything on how to use them, and when I see explanations for the problems I get even more lost than helped.

    Has anyone ever felt in this position, I feel like no matter how hard I try I don't think I will ever even be average in physics. I have an F in the class for sure right now. Have 2 more tests to try and bring it up. But it seems like i'm falling in a black hole and can't do anything about it.
  2. jcsd
  3. Oct 31, 2011 #2
    Some people can't handle physics, I just know that from personal experience. I think that there has to be a very specific type of person, with specific problem solving abilities to excel in physics. Of course, I believe that anybody can do well in physics, as I believe anybody can accomplish something if they want to. But you might not want it enough.

    my ex girlfriend got a 49 in university physics, she talked to the prof and bumped it up to a 51 (she was cute haha). I tried helping her many times but she was, like you, not comfortable with the questions. There was always this look of impending doom on her face when she was doing physics problems, and she did a heck of a lot of questions.

    It is also very possible that the book you are using is not very well suited for you. Which textbook is it?
  4. Oct 31, 2011 #3
    Serway and Jewett 8th ed.

    Also my professor is like russian, or indian or something and I can't understand him, which doubles my problem. I do want a good grade badly, It's just a gap in my mind on how to do physics. I do problems as much as I can, and never understand why the answers come the way they do.

    I am an extremely rational person, yet it doesn't make sense to me how to solve these problems.
  5. Oct 31, 2011 #4
    If you haven't solved any problems during the "hours of studying" it means that you were not really studying physics.If it's an intro course you should read the theory quickly , take some notes and then start doing problems. If you spend more than half an hour on a problem then try another and return later on the hard one.Most lost time is due to getting some idea in your head and trying to do the same stupid thing over and over again. Taking a break from a problem may help you forget the stupid idea or realize that it is stupid.
    Last edited by a moderator: Oct 31, 2011
  6. Oct 31, 2011 #5
    The driving force to learn cannot be greed for good grades. So please rethink: "are you really rational?"
    Forget about the professor. Get hold of ONE good text book. Read it and do not proceed forward unless you convince yourself of the lines. Consult friends/teachers/physicsforums etc. Please forget about grades for a while, if you want grades to come to you instead.
    Remember that I am writing all this because I think it is possible to overcome such difficulty.
  7. Oct 31, 2011 #6
    "Trooling?" I don't get it. I stated a fact which I have observed around me.
  8. Oct 31, 2011 #7
    I do over 10 problems a day, usually taking me 30-45 minutes each, sometimes 20 mins or so. But I can't do problems within 1.5-3 minutes like i'm required to in the class. Some things already make sense to me, and I can work them out, but every time I see a new situation in a problem, I can't instantly recognize it and do it out within 1.5-3 minutes. So doing problems isn't really the problem, I do so many of them.

    Idk, I just feel an extreme hatred towards the class right now. I would love to learn physics, it's just my brain seems to not be able to handle it.
  9. Oct 31, 2011 #8


    User Avatar
    Gold Member

    Sounds familiar. Every time I find an equation for something I have been looking for for a long time, there is allways one factor or figure in the equation with no explanation that tells what it is. So there I am, still lost :biggrin:
  10. Oct 31, 2011 #9
    Can I have a look at a typical question you handle at this level?
  11. Oct 31, 2011 #10
    If you can't distinguish between someone who's Russian or someone who's Indian then you probably aren't cut out to do physics...
  12. Oct 31, 2011 #11
    LOL...this is true.

    Either that or you don't go to class very much.
  13. Oct 31, 2011 #12
    Rigid rods of negligible mass lying along the y axis connect three particles. The system rotates about the x axis with an angular speed of 3.70 rad/s.

    http://img840.imageshack.us/img840/6571/10p026.gif [Broken]

    (a) Find the moment of inertia about the x axis.

    (b) Find the total rotational kinetic energy evaluated from 1/2[Iω^2].

    (c) Find the tangential speed of each particle.
    4.00 kg particle m/s
    2.00 kg particle m/s
    3.00 kg particle m/s

    (d) Find the total kinetic energy evaluated from the sum of 1/2[mivi^2]

    (e) Compare the answers for kinetic energy in parts (b) and (d).

    Professor's first name is Russian based, and his last name is Indian, like from India. He's very skinny and has a tannish skin tone, white hair. It's hard to tell.
    Last edited by a moderator: May 5, 2017
  14. Oct 31, 2011 #13
    Do you typically feel overwhelmed by this type of question? Or is this something that you can handle on a consistent basis?
    Last edited by a moderator: May 5, 2017
  15. Oct 31, 2011 #14
    That's a very simple problem. You need to look at some other textbooks if the one you're using isn't clear enough for you to understand how to do that problem. Do you actually read your book, and following along with the example problems, or do you just skim looking for equations to plug into?

    How far along are you into your calculus classes? If you aren't doing well in calculus you'll never do well in physics.
  16. Oct 31, 2011 #15
    See, just remember that mostly physics theory is to do with somethings called 'laws'. Now what is a 'law'?
    It is a proven truth! Some person saw something happening around him, thought it might be like 'this', so gave an equation with the help of his maths friend to find out quantities of interest.
    I will proceed further once you are comfortable with the above.
  17. Oct 31, 2011 #16
    I can do it if you give me like an hour lol.

    The things I think that might be relevant to this problem are:

    Iα = T
    K = 1/2Iw^2

    My instinct tells me
    I = T/α would be the solution for a, but there is no T that I see.

    Then here is where I go looking for help lol.

    The only things the chapter shows for that problem are:

    I = Ʃ(mi)ri^2
    K_R = (1/2)Iw^2
    Last edited: Oct 31, 2011
  18. Oct 31, 2011 #17
    There is a fundamental fault in your approach my friend. Brush up with the laws and definitions of terms. If possible, write them is a piece of paper and use this paper while you solve initially. Later on you won't need even these.
    Use the laws and definitions only while you solve the questions. It is very straight forward and simple. Keep your mind open and use the laws and definitions to calculate quantity values. Do not attempt to match the answers at the back of your book. keep up with your self-dignity. Take help but also check if you can solve without taking help a few problems on your own totally. Take help to learn rather than to solve assignments. Ask general questions when taking help.
    Like: Instead of asking someone to solve this problem, ask him/her:
    "given a system of connected masses, how to calculate the moment/energy etc."
  19. Oct 31, 2011 #18


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    Gold Member

    I was going to let this go, but I want to correct your reasoning. You did not simply state a fact, you made an inference.

    emphasis mine

    This is not a fact that you've observed, since you have not seen the OP in-person.
    Last edited: Oct 31, 2011
  20. Oct 31, 2011 #19
    That would take you an hour on a test? Yikes!

    Parallel axis theorem will help you for the moment of inertia. Once you have I(they give you w) you can find rotational kinetic energy. from w and r, you know the tangential speed of each of them. using that tangential speed you can find the kinetic energy using 1/2 mv^2. And then you just have to compare your two energy values.

    Can you tell me where your hour would be allocated throughout this question?
  21. Oct 31, 2011 #20
    That's pretty helpful, is there any website on the internet where I can get all of the laws and definitions. My book doesn't do a good job with them.
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