Recent content by Helices

Alright, I've got it now. Thanks!

Homework Statement I'm stuck at one of the derivations for relativistic energy. I've figured out every other single step, but I just can't wrap my head around this one: Prove that: {\frac{d}{dt}} {\frac {mu} {\sqrt{1-u^2/c^2}}} = {\frac {m {\frac{du} {dt}}} {(1-u^2/c^2)^{3/2}}}...

Thanks for the reply. Absorption via the D-line for sodium occurs at 589.0 and 589.6 nm, though these numbers were not given with the problem. I worked it out, taking 589.3 nm as the average wavelength for absorption. I used the relativistic Doppler-effect to determine the velocity of the...

Homework Statement A ray of photons coming from a laser with a wavelength of 589.59nm meets a ray of sodium atoms (A=23) coming from the opposite direction. What is the maximum speed the sodium atoms can have in order to absorb photons? The Attempt at a Solution I thought about...