Recent content by MichalXC

Hi guys, I'm a first-semester junior seeking some quality study resources relevant to the physics GRE. I've heard that ETS has released a few exams from past years... Where (if anywhere) can I find the previous exams in some reasonable format, like PDF? The best I can find is this website...

The force on mass one will be: F_1 = m_1 r''_{1_{CM}} = - k (r_{2_{CM}} - r_{1_{CM}} - l) And on mass two: F_2 = m_2 r''_{2_{CM}} = + k (r_{2_{CM}} - r_{1_{CM}} - l) (Please correct me if this is wrong!)

Is that substitution justifiable even though the two masses are unequal? Certainly the distance from the center of mass to m_1 need not equal the distance from the center of mass to m_2...

Homework Statement I want to find the equations of motion of two masses m_1 and m_2 attached to each other by a spring on a smooth surface assuming m_2 is given an instantaneous velocity v_0 at time zero. Call the unstretched length of the spring l. Homework Equations I want to solve this...

Woo hoo! Found my answer: the http://reference.wolfram.com/mathematica/ref/Split.html" command.

Hi guys, I have a long list of numbers which has only two values, e.g. {1,1,1,0,0,1,0,1,0,0,0...}. The list is ordered as a function of time -- chronologically. I need to see, then, how long the list stays at 1 before going to 0, and then how long the list stays at 0 before going back...

Wow, that is amazing. I'll look through it (with a Mathematica 8 documentation tab open) and try to understand everything. Very much appreciated.

The "space delimiter" method sounds nice. I have no idea what a string tokenizer is, and I'm not sure how to save something as a string, or what that means.

I understand that conceptually, but I would be interested in looking at that parsing assignment -- my C skills are subpar. Thanks.

I also have Mathematica -- not sure how useful it might be in this case...

Hi, I have a bunch of text documents, each of which contains (among other information) the x- and y-positions of 1,000 different 2-D disks at some given time. I want to write a code in C which takes each text document and outputs a visualization of the system at that instant in time. The...

Hi again. Excel (understandably) becomes unresponsive when asked to do some of these calculations. Seeing as much, I would be most grateful if someone could show me how to implement a correlogram (autocorrelation plot) in Mathematica.

Gsal, sorry, I don't know Python. The above-posted formula works great though! Thanks, both, for your replies!

I have a set of 9,999 equi-spaced data points, and I would like to calculate the autocorrelations for ALL lags up to 5,000. In Excel, I want to have this code: =CORREL(B1:B9998,B2:B9999) =CORREL(B1:B9997,B3:B9999) =CORREL(B1:B9996,B4:B9999) ... =CORREL(B1:B5000,B5000:B9999)...

The problem, I think, is that once a particle runs into a boundary or another particle, we reverse the velocity, which places the particle "back on track." However, the velocity reversal will not hold once we place the particle back into an "acceptable region," so the particle will not continue...