2 + 2 = 5

[Brad Barker]

the problem with this is the first assumption is only true with values of x=0
ie the first assumption is a solve-able equation with only one possible value of x.

you cannot get a 0 on one side of an equation and start multiplying & dividing. i forget the name of the rule that says you cannot do this... anyone?

that's part of an axiom for fields. ...the inverse axiom for the "*" operation (which may or may not be multiplication over R): "for all elements c in field F except for 0, there exists an inverse element d such that c*d = e, where e is the identity element."

we exclude 0 from this rule because if it had an inverse, 1 would be the same number as 0, which would cause every element in the field to also be 0!

should be in any linear algebra textbook.

oh, and i think the guy was joking, mac.

 

[Brad Barker]

Brad, help! I have a classical mechanics mid term tomorrow!

I need to learn the following:

About Energy and Angular Momentum

uhh... what about, in particular?

About Central Conservative Forces

orbit stuff sucks. yuck.

Rotating Frames

i really hated that crap. when i took the gre physics exam last month, i skipped the problem about the coriolis effect because i forgot how to use it. i used to know it. :/

Potential Theory

F = -grad(phi). there you go.

Two Body Problem (Fairly easy)

ok, then. lol.

Rigid Bodies

know your moment of inertia tensor(?)

Many Body Systems

never learned. :/

Yeah... this class was supposed to be a senior level class. They decided that sophmores had more use for it since it prepared you for E&M, Quantum, and the GRE's. They forgot to tone it down to our level, though.

bah, i took classical mech 2 as a sophomore. i found EM and quantum to feel absolutely different from mechanics (and each other), with quantum being the easiest to me (oddly enough, especially since i took the graduate sequence).

no lagrangian mechanics or scattering theory? those were the only topics from mech 2 that i actually liked! (and you end up doing scattering in EM and quantum, as well, although EM scattering is a grad-level topic.)

no hamiltonian mechanics? ...that's probably the major thing from classical mechanics that you see in quantum. :/

 

[Poop-Loops]

Lagrangian stuff is easy. Did it last quarter. Scattering theory is a pain, but I did a bit of it in modern physics last quarter and the rest isn't that bad. I mean, all I really need to know is the impact parameter and then I can find the point of closest approach. So it's not that bad.

We were supposed to do Hamiltonian mechanics this quarter. Looks like we'll spend Friday and next Wednesday talking about it. Professor has a hard on for chaos theory so he wants to spend 1 lecture talking about it... Then the final!

My biggest fear is perturbation theory. It makes sense and is simple enough, but I know I'm going to forget one of the perturbations for say, the gravitational potential of a rotating, non-spherical Earth. Although I doubt he'll give us anything that complicated.

I'm still trying to wrap my mind around the gravitational quadrupole and the whole equipotential business with tides.

 

[Brad Barker]

Lagrangian stuff is easy. Did it last quarter. Scattering theory is a pain, but I did a bit of it in modern physics last quarter and the rest isn't that bad. I mean, all I really need to know is the impact parameter and then I can find the point of closest approach. So it's not that bad.

We were supposed to do Hamiltonian mechanics this quarter. Looks like we'll spend Friday and next Wednesday talking about it. Professor has a hard on for chaos theory so he wants to spend 1 lecture talking about it... Then the final!

My biggest fear is perturbation theory. It makes sense and is simple enough, but I know I'm going to forget one of the perturbations for say, the gravitational potential of a rotating, non-spherical Earth. Although I doubt he'll give us anything that complicated.

I'm still trying to wrap my mind around the gravitational quadrupole and the whole equipotential business with tides.

hmm. we didn't do perturbation theory in mechanics, nor all of that messy potential theory.

i liked perturbation theory in quantum 2 and will be spending my summer using it, but it's different when you deal with a quantum system, of course.

what textbook are you guys using? we used thornton and marion. (for the scattering stuff, we used goldstein, since T and M really sucks.)

 

[MonetBass]

Just out of curiousity: do any of you math or stat majors watch "Numb3rs" on Friday nights on CBS? From what I've read they have some really good consultants (don't remember who right off hand), but I'm wondering if you've found any 'mistakes' on that show.

 

[neptoon]

You are in OT, but there is a "bass" forum. Do you need a link to it?

you gotta be kidding me

 

[Poop-Loops]

hmm. we didn't do perturbation theory in mechanics, nor all of that messy potential theory.

i liked perturbation theory in quantum 2 and will be spending my summer using it, but it's different when you deal with a quantum system, of course.

what textbook are you guys using? we used thornton and marion. (for the scattering stuff, we used goldstein, since T and M really sucks.)

We're using Classical Mechanics by Kibble and Berkshire.

Last two quarters (more mathematical physics than anything, but learned most of our math for this class from there) we used Boas's Mathematical Methods blah blah. I think I remember reading that you used it, too.

The hardest part of the class is that the lectures and homework are long and convoluted, but the tests are relatively simple.

I mean, this was our first mid term:

[Invalid or Expired Link Removed]

And here's a lecture and homework solution respectively:

[Invalid or Expired Link Removed]
[Invalid or Expired Link Removed]

 

[Brad Barker]

Just out of curiousity: do any of you math or stat majors watch "Numb3rs" on Friday nights on CBS? From what I've read they have some really good consultants (don't remember who right off hand), but I'm wondering if you've found any 'mistakes' on that show.

no, don't watch.

 

[Kael]

Just out of curiousity: do any of you math or stat majors watch "Numb3rs" on Friday nights on CBS? From what I've read they have some really good consultants (don't remember who right off hand), but I'm wondering if you've found any 'mistakes' on that show.

I've watched it a couple times, but didn't really pay close attention. I'm really not a big TV person. From the maybe two or three episodes I've seen, I couldn't say whether or not there were any mistakes. They didn't really get into any actual math. They just laid out an issue and quickly stated that math could offer a solution without actually showing how it was solved. I don't blame them for not showing explicitly how the problem was solved. A TV show that consisted of proofs would cause 99.9997% of viewers across the country to simlutaneously change the channel to another station.

PS: My father worked homicide for OCPD for 17 years. "CSI" style shows perturbs him. They inaccurately depict how murder cases are worked/solved. Juries are now unfortunately starting to expect CSI style crap in trials. It just doesn't work that way. CSI is Mr Roger's Neighborhood style make believe.

 

[Poop-Loops]

I've heard about the effects CSI has had on crime cases. Really ridiculous. People are actually expecting to see DNA evidence left and right now. Tell your dad that he has my condolences.

Brad, I failed. out of 25 points, I'll be glad to have gotten 5. Apparently most of the class is in the same boat.

Here's the test if you want to see it:

[Invalid or Expired Link Removed]

 

[Brad Barker]

I've heard about the effects CSI has had on crime cases. Really ridiculous. People are actually expecting to see DNA evidence left and right now. Tell your dad that he has my condolences.

Brad, I failed. out of 25 points, I'll be glad to have gotten 5. Apparently most of the class is in the same boat.

Here's the test if you want to see it:

[Invalid or Expired Link Removed]

...well, i could do problem no. 3 and half of no. 1 (although i probably would've tried to crank out poisson's equation or something).

 

[Poop-Loops]

I'm going to wait until Wednesday when I get my test back and possibly drop the course if it's obvious that I can't possibly pass anymore. I have a few friends who are going to do the same... =/

 

[Brad Barker]

I'm going to wait until Wednesday when I get my test back and possibly drop the course if it's obvious that I can't possibly pass anymore. I have a few friends who are going to do the same... =/

when is your quarter over?

i've been out of school for weeks.

 

[Poop-Loops]

I still have next week, and then it's finals week.

Although I started school around October.