Recent content by villiami

Is it possibly that: with photons, there are no frames in which momentum=0. If the p-e pair were produced, there will then be a frame in which momentum=0 (which previously had non-zero momentum photons). Thus mom is not conserved?

Homework Statement This is a special relativity question: Two gamma rays of identical energies E collide with an angle \theta between their velocities. Show that positron-electron pair creation is impossible in the limiting case \theta=0. Find the minimum \theta value for p-e creation to...

Great! Thanks guys. For some reason I was sure that wouldn't work- I'd read something about its value being passed, so modifying it (without referring to its address) wouldn't actually change the object. Thanks again!

Thanks for your help, I'm still unsure how to declare a function to modify a 2D array. I'm trying to make a function to increment a specific element: void flipsite(double* pgrid[][], int n, int m) {*pgrid[n][m] = *pgrid[n][m] + 1.0; }So then in the main function I can write: double...

Have read a million different sites and threads, but still not getting anywhere (damn 1st year java makes addresses incomprehensible!). What changes do I need to make to get these c++ functions to work? //---------Functions //-- A function to increment the (n,m) element void...

So #microstates(A) = N! / n!(N-n)! [Putting n in A] but isn't num(B) = N! / (N-n)!n! as well? [putting N-n into B] I still don't see how to weight them according to volumes.. (thanks for the help so far!)

Homework Statement N atoms are in two boxes, box A: volume=V, and box B: volume=3V. (Assume a atoms make up a low density perfect gas). 1) How many ways can n be chosen, where n=(number of atoms in box A)? 2) Each atom if allocated a spatial state. Assuming that the number of available...

Thanks for that, but it still doesn't let me type something like: f(2) which is what I need for the optimization (where I will enter fminsearch(@f,[0]) to find the minimizing x-value given the constant a and b values) Any ideas?

I have already declared some variable values as (for example): a = 2 b = 3 Now I want to declare a function like: f(x) = x + a - b I will be optimizing w.r.t. x later, so I don't want to enter it as f(x,a,b) (or is it possible to oiptimise w.r.t. just one of the variables?) I tried...

Thanks for the responses, I think I've solved it (partially) by rotating the parts of the curves so the don't double back on themselves. Works well so I'm happy with it!

The data is not paired, i.e. one set might be for x-values 10,20,30,40,50 and the other at 11,17,31.46,...etc In the first version I used spline interpolation when I needed to compare points/curves. (note these are not actually the data points!) Thanks

I'm currently working on a MATLAB program which, given two sets of data each representing curves, will transform (through rotations about the origin and x-y shifts) the first curve so it fits the second one best (so far in terms of sum of squares). I have been able to create a program...

Homework Statement A particle of relative mass 4 travels at velocity v, and collides with a stationary particle with relative mass 1. By considering the zero momentum frame, show that the larger particle can be deflected by an angle of arcsin(1/4) at the most. (Note this is a...

Perfact, I hope a few ideas come out of this new form. Thanks

He goes to BOATING school, not primary. lol