That bit further down the paragraph explains indeed what I’ve been missing so far. (I think).
If the two point events in the example (x1 and x2) are a measure of the length of a particular (solid) object and time interval (t1 and t2) are taken by one particular clock, in that case the point...
The case you ascribe above is true if:
S’ sees a stationary object of 50 m and S’ is having a speed of .6c wrt S. Because then S will see that distance contracted to 40 m.
But the example given is the other way round. S’ sees an object having a velocity of .6c. Therefore S’ must see the...
I had not read this chapter, I dusted off this book to check up on something completely unrelated, and just leafed through when I saw that example.
In following up your advice, I read the last paragraph on page 95. It starts:
All this while the example in question has very precisely...
Hi Doc Al
Thanks for your answer but hmm.
I did realize before I asked this question that simultaneous events in S are not necessarily so in S’. I’ve got no problem with that.
These events happen in S. How can an observer in S see length contraction while x1 and x2 are stationary in S...
Hi all,
Page 94 of Special relativity by AP French has a worked out example that puzzled me.
This is the example:
Frame S’ has a speed v=0.6c relative to S. Clocks are adjusted so that t=t’=0 at x=x’=0. Two events occur.
Event 1 occurs at x1=10m, t1=2E-7s (y1=0, z1=0).
Event 2 occurs...
http://www.google.co.uk/search?q=hysteresis+loop+alnico&hl=en&prmd=imvnsb&tbm=isch&tbo=u&source=univ&sa=X&ei=ikWMUPHVCaGS0QWStIHgDA&ved=0CCMQsAQ&biw=942&bih=445
Hi Undacuva,
Are you asking about the –H demagnetising force? In that case the above websites provide a wealth of information on...
The graph reads 90 degrees, but that’s for a perfect generator. The generator displayed is only very basic, just to give a novice an idea of 3 coils and a rotating magnet. Real life generators are more complicated.
If you would build a generator such as the one displayed you wouldn’t get the...
I don’t think there’s much wrong with your analysis.
The picture you downloaded is just very basic. If you had a generator like that your resulting waveform would be highly irregular, it wouldn’t give a nice sin form. All you would get is some sort of spike when a pole nears a coil. Like you...
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/solenoid.html
The formula shows that for a long (L >> R) electromagnet: B=μ0 N/L I.
Perhaps I can use this formula for your case and say that if the current remains the same but N increases, what will happen? As long as L also increases...
Hi Renato, welcome to PF.
What’s so strange about having opposite currents at different places in the tube?
Those 2 currents run round the circumference of the tube and are roughly separated by a distance approx. the length of the magnet. I say roughly because in this space they...
Ah, I finally found what I was looking for.
http://en.wikipedia.org/wiki/Near_and_far_field#Regions_and_their_cause
Some quotes from that article.
(My bold script)
This is all very close to how I imagine power transfer takes place in an air core transformer. Note that I’m especially...
This would work exactly the same as it happens in an antenna. It is well known that a wave front of speed C leaves the antenna. Where do those lines go, how far, what when the current is max, what when reversing etc. there’s no difference.
No. Again, exactly the same as a coil antenna would...
http://www.youtube.com/watch?v=UvHCQswnjEg&feature=related
This is not a bad demo of what I’m going on about. The magnetic field is expanding from the primary coil. Ofcourse there's much more to it then what is shown here. Remarkable that he says: nobody really knows how this works! I'll have...
Yes you are correct here. That was once one of my conclusions in another thread here at PF. That’s why I want to see a good Wikipedia article showing all fields in a simple transformer. Including flow of energy.
No it does not demand that. I have indicated from the start that such fields flow...