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seen Apr 21 at 15:59

NTS


Feb
1
comment How does the voltage between two charged sheets change if change their distance
@BenediktBauer You can't get a general formula in the case in which you can't ignore boundary effects. When you need values of field or voltage in complex cases like that one, you generally use numerical methods (computers) to get numerical values, but you can't get formulas. That's how pictures like the first one in my answer are done, by numerical approximations, that with computers can have huge preccisions.
Feb
1
answered How does the voltage between two charged sheets change if change their distance
Feb
1
accepted Irreversible process
Feb
1
comment Irreversible process
I'm sorry for the lack of information, the expansion is not free, it's a fast expansion to an external pressure of 1 bar, being the initial internal pressure 4 bars. Anyway, you helped and following "more or less" your same path I got the correct result. Thanks.
Jan
31
revised Irreversible process
added 230 characters in body
Jan
31
asked Irreversible process
Jan
30
comment Was the choice of red/green colors for traffic lights a happy coincidence?
I never learnt that in Secondary school...
Jan
28
comment Finding orbital eccentricity
Ok, good morning, great exam (not related to this), and I finally get the correct result, thanks for your help.
Jan
28
comment Why don't we use quater-circular dees instead of semi-circular dees in a Cyclotron
No idea, but I guess it's cheaper that way (2 oscilators, instead of 4), and you can still get high speeds.
Jan
27
comment Finding orbital eccentricity
So if I get $r_{max}$, it will be $a=(r_{max}+r_{min})/2$?? Since the maximums values are at extreme points of the major axis...
Jan
27
accepted Finding orbital eccentricity
Jan
27
comment Finding orbital eccentricity
Ok, so using your second equality I get $a(e)$, by substituting $r_{max}=r(\pi)$, which is the max value of the function, then I plug that into the $a$ of the first one and I will have an equation with an unknown variable. That's a long calculation, it's 00:00 here and I have an exam tomorrow in the morning so I will leave them for tomorrow, but thank you very much, you helped a lot.
Jan
27
comment Finding orbital eccentricity
I'm stupid, I confused your $a$ with the $a$ of the wiki page you sent me, so I find your $a$, which will be the max value of the function, right?
Jan
27
comment Finding orbital eccentricity
Thanks for the help, I'm now doing $r(\theta)=R_{max}$, substuting $\theta=0$, the point of the maximum of that function, and getting $e$ out of the equation, I have the rest of the values, but I'm getting a result for $e=3\cdot 10^6$. That's imposible. (I found a mistake in my calculations, let me revise them)
Jan
27
comment Finding orbital eccentricity
@DavidZaslavsky Done
Jan
27
revised Finding orbital eccentricity
added 530 characters in body
Jan
27
asked Finding orbital eccentricity
Jan
27
comment Fast question about Lagrangian
I think I got it, thanks
Jan
27
comment Fast question about Lagrangian
@Joe I edited it to try to explain it better.
Jan
27
revised Fast question about Lagrangian
added 166 characters in body