Recent content by Anachronist
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I E-field around charged finite wire - intractable or not?
Wow, that's incredible, and far more than I expected. Really helpful to see a plot of the isosurfaces, as well as a not-terribly-complicated solution for p=1. To your last question, yes, that impacts the utility of this approach, because it isn't quite what I expected to see. I was going for...- Anachronist
- Post #10
- Forum: Electromagnetism
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I E-field around charged finite wire - intractable or not?
Yes, that is exactly what I came up with for the charge density with respect to z. And last night while falling asleep I imagined an integral similar to what you describe. I am wondering if there are certain values of p for which this is simpler and closed form. Because this is for generating...- Anachronist
- Post #8
- Forum: Electromagnetism
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I E-field around charged finite wire - intractable or not?
Yes, that was sloppy language on my part. I erred in calling it a "wire", I meant a 1D line-segment of charge rather than a single point charge, and that would need to be a thin rod made of an insulator. Because this is a metaball graphics application, I thought a field generator function for...- Anachronist
- Post #7
- Forum: Electromagnetism
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I E-field around charged finite wire - intractable or not?
Good to know. I want to avoid a numeric solution if possible. Yes, the wire could be approximated by straight segments. As the length of each segment approaches zero, I would have some sort of integral, I think.- Anachronist
- Post #3
- Forum: Electromagnetism
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I E-field around charged finite wire - intractable or not?
I have a problem I'm trying to solve for metaball graphics application. I'm going to use an electric field analogy here, but it isn't actually an electric field because the density falloff is ##1/r^s## rather than ##1/r^2##, where ##s## is some arbitrary constant like 3.6 that determines the...- Anachronist
- Thread
- Charge density Charge distribution Wire
- Replies: 10
- Forum: Electromagnetism
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ChatGPT spin off from: What happens to the energy in destructive interference?
Why? Why do people do this? You never get a satisfactory answer when asking for factual information that normally requires some research or study to find. ChatGPT gives you hallucinations instead. I asked it to give examples of books published by university presses that discuss fringe views...- Anachronist
- Thread
- Replies: 65
- Forum: General Discussion
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What Level of Math is Best Before Taking Physics?
Welcome. I graduated with a Bachelor's degree in physics, and like you, I was always mediocre in math, but interested enough to maintain a mathematics blog that focuses on empirical math. I'm retired now, and during my career I'd say that beyond algebra, trigonometry turned out to be the most...- Anachronist
- Post #4
- Forum: New Member Introductions
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Programs Help me decide: physics or chemistry?
I've been there (I'm retired now). I would choose physics. Chemistry is actually physics, when you get right down to it. With a physics degree, you can actually get employment in engineering, as I did. A coworker who actually got his PhD in physics decided he wanted to go into medicine, and now...- Anachronist
- Post #37
- Forum: STEM Academic Advising
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B Generating Energy from Molecular Motion
We can already make machines that take advantage of a "molecule's always-moving energy". That's thermal energy, and machines that convert heat into other forms of work already exist. A stirling cycle engine does converts heat into mechanical motion, and thermionic generators can convert heat...- Anachronist
- Post #9
- Forum: Classical Physics
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B Circle tangent to two lines and another circle
Thanks, I believe I figured it out. From the diagram, I have ##x_1^2+y_1^2 = (r+R)^2## where ##R## is the radius of the unknown circle. I also know that ##x_1=a+R## and ##y_1=b-R##. That means ##(a+R)^2 + (b-R)^2=(r+R)^2## and I have a quadratic expression with one unknown, ##R##. That can...- Anachronist
- Post #3
- Forum: General Math
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B Circle tangent to two lines and another circle
I'm trying to solve this for a model I'm making in OpenSCAD. Given a circle of radius r centered on the origin, and two perpendicular lines at x=a and y=b, where is the center (x1,y1) of a circle that is tangent to both lines and the centered circle? Here's a picture: I thought it would be...- Anachronist
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- Geometry Tangent line
- Replies: 2
- Forum: General Math
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Music Cover songs versus the original track, which ones are better?
The one that amazed me was Dolly Parton's bluegrass version of Collective Soul's hard rock song "Shine". I'm not a fan of country music, but honestly, it's difficult for me to decide which I like better. Compare them yourself: Collective Soul's original version Dolly Parton's version It helps...- Anachronist
- Post #834
- Forum: Art, Music, History, and Linguistics
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Minimizing the friction of the end of a lever against the top of a moving piston
Thanks. I managed to redesign it so the rocker lever moves only 17°. There will be some sliding, perhaps mitigated with a bit of lubrication.- Anachronist
- Post #22
- Forum: Mechanical Engineering
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Minimizing the friction of the end of a lever against the top of a moving piston
For this project I'm assuming here that the lateral force wouldn't be much different from the lateral forces experienced by the switches under a keyboard, in which the forces aren't perfectly axial to the switch. Yes, you're correct, this is basically a cam. Hopefully the curved pad design on...- Anachronist
- Post #19
- Forum: Mechanical Engineering
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Minimizing the friction of the end of a lever against the top of a moving piston
The stroke is actually 4 mm, with 2 mm being "dead" and the other 2 mm making electrical contact. With a lever pivot about 8 mm away, that's about 26° but I am not planning for the entire stroke to be used.- Anachronist
- Post #17
- Forum: Mechanical Engineering