Communities

Writing
Writing
Codidact Meta
Codidact Meta
The Great Outdoors
The Great Outdoors
Photography & Video
Photography & Video
Scientific Speculation
Scientific Speculation
Cooking
Cooking
Electrical Engineering
Electrical Engineering
Judaism
Judaism
Languages & Linguistics
Languages & Linguistics
Software Development
Software Development
Mathematics
Mathematics
Christianity
Christianity
Code Golf
Code Golf
Music
Music
Physics
Physics
Linux Systems
Linux Systems
Power Users
Power Users
Tabletop RPGs
Tabletop RPGs
Community Proposals
Community Proposals
tag:snake search within a tag
answers:0 unanswered questions
user:xxxx search by author id
score:0.5 posts with 0.5+ score
"snake oil" exact phrase
votes:4 posts with 4+ votes
created:<1w created < 1 week ago
post_type:xxxx type of post
Search help
Notifications
Mark all as read See all your notifications »

Search

Advanced Search Options

To further refine your search, you can use additional qualifiers such as score:>0.5. For example, the search score:>=0.5 created:<1y grammar would return only posts mentioning "grammar" that have a score >= 0.5 and were created less than a year ago.

Further help with searching is available in the help center.

Quick hints: tag:tagname, user:xxx, "exact phrase", post_type:xxx, created:<N{d,w,mo,y}, score:>=0.5

Filters
231 posts
 
84%
+9 −0
Q&A Unusual way to write spacetime coordinates/metric: Is there any downside?

There is no problem with the approach you suggest: it's equivalent to deciding to use seconds and light-seconds as your units for space-time four vectors instead of light-meters and meters. (I actu...

posted 3y ago by dmckee‭  ·  edited 3y ago by dmckee‭

Answer
81%
+7 −0
Q&A Unusual way to write spacetime coordinates/metric: Is there any downside?

In special relativity, spacetime coordinates are normally given as $$(ct, x, y, z) \tag{S}$$ with the metric being either $$g = \operatorname{diag}(-1,1,1,1) \tag{+}$$ or $$g = \operatorname{d...

1 answer  ·  posted 3y ago by celtschk‭  ·  last activity 3y ago by dmckee‭

81%
+7 −0
Q&A What is "order" and "disorder" in entropy?

"Disorder" and "order" don't mean anything with regards to entropy. This is a common "science popularization" level description of entropy that is "not even wrong" in that, as you've seen, these te...

posted 2y ago by Derek Elkins‭  ·  edited 2y ago by Derek Elkins‭

Answer
81%
+7 −0
Meta What should this community's policy on "explain like I'm five" and similar statements be?

Several questions have been posted recently where the user asking the question points to an extremely limited knowledge of the relevant field by asking of others to "explain like I'm five" (years o...

2 answers  ·  posted 2y ago by Canina‭  ·  last activity 2y ago by Olin Lathrop‭

80%
+6 −0
Meta What should this community's policy on "explain like I'm five" and similar statements be?

My opinion is that such qualifiers, especially when combined with very general questions about specialized subjects, are not helpful. Generally, the tone of the question will be indicative of the ...

posted 2y ago by Canina‭

Answer
80%
+6 −0
Q&A Would we need Alternating Current if superconducting wires existed?

The major advantage of AC is that is can be easily transformed to different voltages. This is important because current transport is most efficient if the currents are low (because the losses are p...

posted 3y ago by celtschk‭  ·  edited 3y ago by celtschk‭

Answer
80%
+6 −0
Q&A What is inflation in cosmology?

I am having trouble understanding what a cosmic inflation is. Please try to suffice an explanation for non physicists / non formal students for physics / general audience. I understand that an ...

2 answers  ·  posted 3y ago by deleted user  ·  last activity 3y ago by deleted user

Question inflation cosmology
80%
+6 −0
Meta What should our policy be toward rudeness?

This is a small site with 5 questions in 30 days, rudeness is just going to drive people asking questions away. Casual users seeing newbies get insulted for not knowing things isn't going to make ...

posted 3y ago by Charlie Brumbaugh‭

Answer
80%
+6 −0
Meta What should our policy be toward rudeness?

What should our policy be toward rudeness? I don't think being blunt is a problem, but I do think that calling into question the OP's intelligence is a problem. For example, I don't think there's ...

2 answers  ·  posted 3y ago by Technically Natural‭  ·  last activity 3y ago by Charlie Brumbaugh‭

Question discussion
80%
+6 −0
Q&A How do constraints work in Lagrangian systems?

As apparently seems par for this book, the theorem statement you're paraphrasing involves vaguely defined or completely undefined terms. For example, it talks about "admissible (smooth) paths" but ...

posted 3y ago by Derek Elkins‭

Answer
80%
+6 −0
Q&A How do constraints work in Lagrangian systems?

I have a question about the discussion of constrained Lagrangian systems in the book Mathematical Aspects of Classical and Celestial Mechanics by Arnold et al. (section 1.2.5). The Lagrangian syst...

1 answer  ·  posted 3y ago by Technically Natural‭  ·  last activity 3y ago by Derek Elkins‭

80%
+6 −0
Meta Welcome to Physics!

Welcome to the Codidact site for Physics! We're glad you're here and we're excited to see what you will build. This community is starting "from scratch", without importing Q&A from other site...

0 answers  ·  posted 3y ago by Monica Cellio‭

80%
+6 −0
Q&A How does probability conservation work in Dirac's original formulation of relativistic QM?

I asked this question on Stack Exchange, and didn't get an answer, but maybe someone here will be able to help. In non-relativistic quantum mechanics, the normalization condition for position eige...

1 answer  ·  posted 3y ago by Technically Natural‭  ·  last activity 3y ago by Derek Elkins‭

80%
+6 −0
Q&A Should I always write units in equation no matter if it looks like variable?

In short: Yes. And there are standard ways to distinguish variables from units. Let me explain in detail. In physics, we deal with physical properties of objects and systems. Those quantities can ...

posted 2y ago by celtschk‭  ·  edited 2y ago by Canina‭

Answer
77%
+5 −0
Q&A What does Lagrangian actually represent?

There's not really a fundamental interpretation of the Lagrangian because the Lagrangian that describes the dynamics of a system isn't unique - more than one Lagrangian can yield the correct equati...

posted 2y ago by HDE 226868‭  ·  edited 2y ago by HDE 226868‭

Answer
77%
+5 −0
Q&A What's the meaning of "outdated" in physics?

That sounds like something I'd say, so I'll explain this from my point of view, in particular regarding 'relativistic mass'. An 'outdated' theory or piece of terminology isn't typically mathematic...

posted 2y ago by Mithrandir24601‭

Answer
77%
+5 −0
Q&A Should I always write units in equation no matter if it looks like variable?

I am not sure if it is suitable in the site. I am asking the question here cause Olin and Celtschk said it here. They told me to use unit in every "single line" (Nope! They didn't say like it. Oli...

2 answers  ·  posted 2y ago by deleted user  ·  last activity 2y ago by Canina‭

Question units
77%
+5 −0
Q&A Why is it forbidden for two photons to turn into one?

In the context of quantum field theory, why is it impossible for two photons (or other massless bosons like gluons) to collide and produce a single photon? This kind of a process is supposed to be ...

2 answers  ·  posted 11mo ago by Technically Natural‭  ·  last activity 10mo ago by Derek Elkins‭

77%
+5 −0
Q&A How exactly do eddy currents slow down objects moving though a magnetic field

As the pendulum swings, it experiences a changing magnetic field from the externally fixed magnets. Any changing magnetic field causes eddy currents in a conductor. Since these conductors aren't ...

posted 1y ago by Olin Lathrop‭  ·  edited 1y ago by Olin Lathrop‭

Answer
77%
+5 −0
Meta New Category ideas

The Papers Category I don't think the "Papers" category would work well for physics. It would get a lot of spam, and I think it would be much more limited in usefulness than the one on Electrical ...

posted 3y ago by Technically Natural‭

Answer
77%
+5 −0
Q&A Is it rational to freeze water bottles during colder nights, and place them in front of a fan during warmer days?

TL;DR Yes, that will work. It may not be practical, but that is a separate issue. There are two measurements routinely used for cooling in the US: BTU = British Thermal Unit = heat to raise the...

posted 3y ago by manassehkatz‭

Answer
77%
+5 −0
Q&A Should Earth's moon colonies being deep underground ensure natural heating?

Moon colonies should be underground, but not for thermal management reasons. It's easy enough to regulate temperature closer to the surface. Indeed, the bigger problem will be getting rid of the wa...

posted 3y ago by Dave Tweed‭

Answer
77%
+5 −0
Meta When selecting needs author attention it doesn't reach to moderator

Could be either [status-declined] or [status-bydesign], but this seems more of a request than a bug report, so I went with declined. This is how this one is supposed to work. A common and misguide...

posted 2y ago by ArtOfCode‭

Answer
77%
+5 −0
Q&A How does probability conservation work in Dirac's original formulation of relativistic QM?

I recommend https://www.mat.univie.ac.at/~neum/physfaq/topics/position.html which, while a bit hard to read, is more comprehensive and written by someone more authoritative than me. My research did...

posted 3y ago by Derek Elkins‭

Answer
75%
+4 −0
Meta New Category ideas

Electrical Engineering has a Papers category, for writing short articles of original work, which I for one think is a great idea. Similar to such a category would be a 'paper review' category, whe...

1 answer  ·  posted 3y ago by Mithrandir24601‭  ·  last activity 3y ago by Technically Natural‭