Recent content by bhimberg

\chi_m = - \frac{Z e^2 n \mu_0}{4 m} <p^2> My understanding is that n = N/V, where the volume is the volume of a unit cell containing Z electrons (in this case n = \frac{1}{a^3}). The m in the denominator is related to the larmor frequency and, for a hydrogen atom, should be the mass of a...

Thanks Zina, Vanadium. Re: Vanadium Definitely not what I want to hear, but perhaps what I need to hear. Basically this means that my GRE scores are useless to me until next fall. This puts me in a position where I will have to apply this coming week to schools at the bottom of my list if...

So I'm studying for the physics GRE and plan on taking it this April. While I understand the deadline for admissions to most universities is right up until the semester begins, I also understand it is a first come, first serve deal. Are most slots going to be filled by May, when the scores...

My father managed to earn his in 4-5 years while working a full time job and cooking dinner most nights (for his family of 5). He even got very ill in the middle of it (looked like cancer, turned out to be auto immune). Given that his full time job is 40+ hours a week, and he does actually...

I thought I'd give this problem a shot, so here it goes. First, I find the time it takes for the object to hit the ground once its off the edge of the table: 0.500 m = (1/2) (9.8 m/s^2) t^2 -> t = Sqrt(1/9.81) -> t = 3.19E-1 s next, I solve for the velocity in the x direction as the...

But aren't there two Ts? One T for the tension due to the weight, another due to M? 1) d(theta)'' = -x'' -y'' 2) Mx''=T 3) my''=T-mg 4) (Torque)=T x r = Tr (since r and T are always orthogonal) Four equations, 4 unknowns. If the T in 2 is the T in 3. Yet if they are the same, the...

Thanks, you've helped a ton. In response to your request: The weight has the force of gravity acting on it, -mg. It, and here's the confusing part, also feels the tension in the string caused by the spool (mass M), which is moving in the -x direction, and is thereby translated to the...

I ended up using T=mg-Mx'', and crossing this with torque to find the rotational acceleration of M. That is, the total tension instead of the tension on M due to m. (torque)=|(mg-Mx'') x r|= (mg-Mx'')r. This made sense to me since, once Mx''=mg, the tension disappears. Is this correct...

Homework Statement A spool with radius r and mass M sits upright on a table, a distance l from the edge. The string hangs off the edge of the table with a mass m attached. The table is frictionless: what will the velocity of the weight be when the spools center of mass reaches the edge of...

Its a little known fact that physics kills. It usually takes years though: the first signs of distress typically occur during "tenure". Once through this life changing stage, the subject slows down until they hit the next phase. Retirement. In all seriousness, I thought I would mention...

Honestly all those courses require math, so really it seems you just get headaches when you do work. Could be eye strain. First thing I would do in general is look at how much sleep you're getting. Too much is just as bad as not enough. The important thing is consistency. Most people...

Physics classes can be hard. There is a reason people cringe when you tell them you're pursuing physics. Physics classes can be hard. That being said, "Genius is one per cent inspiration, ninety-nine per cent perspiration" - Einstein. Even if you can't get an A in the class, as long...

You should join up with your local SPS chapter. I believe you get a 1 year free subscription for doing so. Not to mention you'll be getting involved with students of like mind.

We have lecturers and I believe senior lecturers. Never heard of a "reader" though.

Hell, I pretty much lived on the physics floor when I was in school last year (going back this Spring). We had an undergraduate lounge, and I studied, napped and ate there. Whenever I had a question the profs were a floor up. I picked their brains and learned from it, and most where happy...