Recent content by iamaelephant

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    What caused inflation to stop?

    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...
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    Constraint Equation? Multivariate calculus

    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...
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    Constraint Equation? Multivariate calculus

    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...
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    Special Relativity, accelerating frames, proper time

    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.
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    Special Relativity, accelerating frames, proper time

    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 -...
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    Special Relativity, accelerating frames, proper time

    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...
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    Confusion in special relativity - total newbie

    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...
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    Capacitance of a parallel plate capacitor with two dielectrics

    Excellent, thanks so much. I'm stoked I got this one right, a rare hit for me in EM :P
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    Capacitance of a parallel plate capacitor with two dielectrics

    [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...
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    Could a Solar Flare destroy life on our planet?

    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...
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    Question - Tilt of the Analemma

    I'm going over some simple stuff for an astronomy exam and it occurred to me that I'm not sure what causes the tilt in the solar analemma. It won't be a question in the exam but it got me curious. It seems that the analemma has a different tilt in every picture I look at. I would assume that it...
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    Understanding Closed Forms of Series | Quick Explanation and Tips

    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.
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    Understanding Closed Forms of Series | Quick Explanation and Tips

    Thanks a lot! Heh, always seems so simple when someone explains it :)
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    Understanding Closed Forms of Series | Quick Explanation and Tips

    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...
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    How to find any naked-eye object

    So this is only for people in USA? Disappointing.
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