Recent content by chi_rho

Three conditions must be met in order for the Poisson Distribution to be used: 1) The average count rate is constant over time 2) The counts occurring are independent 3) The probability of 2 or more counts occurring in the interval $n$ is zero Simply, why must these conditions be met for valid...

Say I have {S_{x}=\frac{1}{\sqrt{2}}\left(\begin{array}{ccc} 0 & 1 & 0\\ 1 & 0 & 1\\ 0 & 1 & 0\\ \end{array}\right)} Right now, this spin operator is in the Cartesian basis. I want to transform it into the spherical basis. Since, {\vec{S}} acts like a vector I think that I only need to...

Thanks for all of your help, I was finally able to figure it out because of your useful directions!

Yeah, that was just a typo. The ##\frac{1}{r}## definitely needs to be there. Sorry about that.

So I wrote ##r## in terms of ##r_{i}## , but I just needed some dummy index so really any can work. The problem I ran into was in finding the final term: \begin{align*} -\frac{4\pi}{3}\delta_{km}\delta(\mathbf{r}) \end{align*} I know the derivative I performed only works with ##r \neq 0##, and...

I am currently reading Modern Electrodynamics by Andrew Zangwill and came across a section listing some delta function identities (Section 1.5.5 page 15 equation 1.122 for those interested), and there is one identity that really confused me. He states: \begin{align*} \frac{\partial}{\partial...

Ok that makes sense! Thanks!

How are they still considered to be in orbit if they are traveling to another planet, not around? Can we consider anything traveling through space to be in an orbit of some type?

If I'm traveling on a spaceship at a constant velocity (say 10000 m/s) towards Mars will I feel weightless, or will I feel nearly weightless because I will still be slightly affected by gravity? I know that when astronauts are in the ISS they feel weightless because they are in a constant...

I know gravity is a conservative force field and can be treated as such for all intents and purposes, but I was just thinking that in order to show that a vector field is conservative that vector field must be defined everywhere (gravitational force field is not defined at r=0). I was thinking...