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Spring-type questions

Posted: Sat Sep 20, 2008 3:05 pm
by dmahler
Hey guys, I've been doing the practise tests and I see at least 2 questions having to do with multiple springs, normal modes etc. Does anyone have any suggestions on where to read about this? I was taught this stuff at one point, but its a little hazy. Thanks,
-Dylan

Re: Spring-type questions

Posted: Sat Sep 20, 2008 4:37 pm
by dmahler
Sorry to do this, but I have one more question. Anyone have a good text they use for Electronics questions? And electromagnetic theory?
Those are the three types of problems I am currently weak in, springs, electronics, and E&M. For spring stuff I am currently using Young and Friedman, for electronics I am winging it, and for E&M I am using Griffiths (this may be huge overkill). Any help would be great. Thanks,
-Dylan

Re: Spring-type questions

Posted: Mon Sep 22, 2008 9:33 pm
by dmahler
No one? Especially the spring-type questions.
-Dylan

Re: Spring-type questions

Posted: Mon Sep 22, 2008 11:38 pm
by Juston
I was never strong with normal modes myself, but a good text to refer to for a lot of classical mechanics stuff is the one by Taylor. However, from what I remember from the practice tests, some of the pendulum problems only required a qualitative understanding of the normal modes, so I'm thinking that you may be able to eliminate answer choices by first developing a mental picture of what the normal modes look like.

For electronic circuits, I look at my freshman physics texts (Serway, Giancoli). A modern physics text (or an extended version of a freshman text like Halliday/Resnick) is good for things like semiconductors, diodes, transistors and stuff. For E&M, Griffiths is the best, but I agree that it's overkill.

Re: Spring-type questions

Posted: Mon Aug 24, 2009 10:39 pm
by sravanskarri
@mahler:
If you are still looking for some good references on normal modes. Check the open courseware video lectures from MIT ( Physics 2: Vibrations and Strings ). Dr.Walter Lewin explains these very well.

Re: Spring-type questions

Posted: Tue Aug 25, 2009 4:27 am
by nathan12343
One of the best ways to do these types of questions is to write down the Lagrangian of the system and solve for the normal modes by using the Euler-Lagrange equations. This reduces the problem to taking a few derivatives and doing some algebra. Also, the method described on the wikipedia page on Normal Modes (substiuing solutions of the form e^(iwt) and then solving for w) would probably be applicable if you can write down equations of motion for whatever masses are in the problem.

A good reference for this material would be Thornton & Marion.