Recent content by iamaelephant

So I'm reading about the inflationary period and something occurred to me that never seems to be addressed in the popular physics books - what caused inflation to stop? So I buy the inflation argument, the evidence seems sound, but why would the universe expand so extraordinarily quickly for a...

Thanks a lot for your help, I think I nailed it but I'd really appreciate if someone could give me some feedback on my work. Here's what I got: If marbles cost $12, cheese costs $18, total money is $216 then we set up the constraint equation 18c - 12m - 216 = 0 m = (216-18c)/12 therefore...

Homework Statement This is a second (university) year calculus problem dealing with calculus of multiple variables. In economics, utility is a measure of the relative satisfaction from, or desirability of, consumption of goods. A utility function u = u(a,b) gives the utility from consuming...

Also just so I'm clear, does "proper time" mean the amount of time that has passed in the frame of some object, regardless of whether it is accelerating or not? The words don't even appear in my textbook unfortunately.

Hi Dick, sorry for the late reply, busy weekend. Thanks for your help, I think I got it but I'd appreciate if you (or someone) could check to see if I did things right. dt' = \frac{dt}{\sqrt{1 - \frac{v^2}{c^2}}} = \frac{dt}{\sqrt{1-\frac{(at)^2}{c^2}}} = \frac{dt}{\sqrt{1 -...

Homework Statement A particle has a constant acceleration in a laboratory from 0 to 0.5c in 2 seconds. What time elapses for the particle (i.e. what is the proper time for the particle)? Hint You will have to integrate the proper time of the particle over the two seconds as measured in the...

I'm sure it's a stupid question but this is my first crack at SR so help would be great. Homework Statement Frame S' has a speed of 0.7c along the x axis relative to frame S. Clocks are adjusted so t=t'=0 at x=x'=0. An even occurs in S at t1 = 3 x 10^7s at x1 = 40m. At what time does the...

Excellent, thanks so much. I'm stoked I got this one right, a rare hit for me in EM :P

[SOLVED] Capacitor with 2 dielectrics Homework Statement A parallel plate capacitor of plate area A and spacing d is filled with two parallel slabs of dielectric of equal thickness with dielectric constants k1 and k2, respectively. What is the capacitance? Homework Equations You tell me. The...

I saw a (pretty lame) documentary a while ago about end-of-the-world scenarios that included something very similar to the scenario posted above. A severe coronal mass ejection caused the magnetosphere to fracture and was quickly followed by a solar flare which fried a good portion of the...

Is anyone able to give me some hints or links on how to find the closed form of any series? I'm really stuck here and my textbooks don't seem to cover it.

Thanks a lot! Heh, always seems so simple when someone explains it :)

Hi, I'm just going through an example of closed forms of series in a textbook (Anton Calc) and I'm wondering how they got to this step, can someone please explain it to me? Also, any hints on formulating closed forms would be greatly appreciated, they are not covered in detail in my text. Thanks...

So this is only for people in USA? Disappointing.

Am I blind, or does that article not say when the probe is due to reach Vesta? It says it will arrive at Ceres in February, 2015, but nothing about when it arrives on Vesta. Interesting stuff anyway, I hope the "asteroid hop" goes off without a hitch.