Centrifugal force intuitive explanation
Does centrifugal force exist?
When can I use a forward declaration? I am looking for the definition of when I am allowed to do forward declaration of a class in another class's header file:  Am I allowed to do it for a base class, for a class held as a member, for a class passed to member function by reference, etc. ? My website title shows up slightly different from what's in my title tag, only in Google search When writing a book and referring to a female and male aged 18–25, what term would be most appropriate? Boy and girl seem too young, whereas man and woman seem too old.  Example sentence:     A boy/man emerged from the shadows.   Edit: I think the word I am looking for is similar to 'guy' but less American and colloquial. Any thoughts? How to find what device a file is on (and use that in a script)? I want to find out what device my file is on so that I can use it in a script. I can get this far:  $ df  . Filesystem   512-blocks      Used Available Capacity  Mounted on /dev/disk0s2  498438976 294369520 203557456    60%    /   but this output feels too clumsy; is there a better way than parsing this to get the first 'word' of the second line?  What I really need is something like this so I can pipe it to the next command:  $ somecommand . /dev/disk0s2   How can I achieve this, preferably without resorting to string hacking the 'df' output? Is a +1/+1 counter I get from, say Unleash or Undying different than +1/+1 from something like  or ? Using notify-send with cron What are the practical differences between 256-bit, 192-bit, and 128-bit AES encryption? I am trying to understand the permission usage for the cp command in unix.   What are the permissions required for copying a file into a directory What are the permissions required for copying out of a directory?   I'm assuming for my first question, the directory will need execute permissions to perform the operation and the file will need read permissions to read the binary of the file and then the output file will need write permissions.  For the second the directory itself would need execute permissions to perform the copy operation and the file would need read permissions to extract the data from the file.  Can anyone tell me if my logic is flawed? I've recently set up the compiz cube again, and I was very happy to find that that flickering window glitch is gone! However, the cube reflection and deformation plugins are also gone.  I am running a fresh 12.10 install, and I have every compiz plugin package installed (including compiz-plugins-extra, which supposedly contains everything that compiz-fusion-plugins-extra package used to have), but those two plugins are still missing. I haven't been able to find anyone with the same problem.   Any ideas? (thanks!) Why is it disadvantageous in graduate admissions to have a higher degree? indicates that holders of a master’s degree are held to higher standards when it comes to graduate admissions. The stated requirements for some graduate programs () also outright exclude applicants with doctoral degrees. These seem to be saying that holding a higher degree prior to application is a disadvantage (a fatal one in the case of a PhD). This also applies to private universities: Stanford  (at least in computer science); .  I don't understand why:   If there are two applicants, Alice and Bob, who have achieved largely similar things, it seems logical that both should have a roughly equal chance of being admitted. However, based on JeffE's answer, if Alice has a Masters degree while Bob does not, it's Bob that gets admitted instead of Alice. JeffE's answer even indicates that if Alice has achieved slightly more than Bob, it's still Bob that gets admitted.  If graduate admissions is looking for students that are capable of succeeding in its program, then Alice should be more likely to succeed than Bob since she's already had some experience of graduate study. This should be even more the case if Alice already has a PhD – if she can do it once, she should be able to do it again.    JeffE's answer indicates that since Alice has had more opportunities than Bob, she should also be held to higher standard. However it should also be true that Alice has already achieved what Bob has yet to and in fact might not be able to achieve. Further, JeffE's answer seems to be saying that Alice should do the academic equivalent of financial engineering and pass her graduate-level courses &amp; thesis without getting a master’s degree even if she qualifies for it, which sounds silly.  As for applicants with PhD degrees, my first guess would be that this is because , and the university is acting in the applicant's best interests. However if this is the case, then this is effectively telling the applicant "I know what you want better than you do", which also sounds silly. UC Berkeley's requirements also seem to be saying that if someone with a CV worthy of a tenured position were to apply for a PhD student position, the university will say "no" even though it's clearly better in their best interests (in terms of research output) to say "yes".   Presumably I'm misunderstanding something because if this behavior were irrational, it would already have been changed. What am I missing?  EDIT: I wonder if things are different in programs where the student is involved in research directly without spending time on coursework? Programmatically create a user and assign a role I'm programmatically creating a user with the following code.  $newUser = array(   'name' =&gt; $mail,    'pass' =&gt; 'password',  // note: do not md5 the password   'mail' =&gt; $mail,    'status' =&gt; 1,    'init' =&gt; $mail,   'roles' =&gt; array(5) ); $user = user_save(null, $newUser);   I have got a role with the role ID equal to 5; when I create the user, in the table "users_roles" there is only a row with the value 0 for the role ID, but if I print the user object with var_dump(), it looks like the roles are created.  What am I doing wrong? Sum over all non-evil numbers How to set a maximum execution time for a mysql query? How to uncover a table column wise in Latex beamer I have a table with 7 columns and want to show the first 5 at once, and then  the 6th and 7th on consecutive slides.  This is the code I have for now:  \begin{frame}{Наслов}     \begin{itemize}         \item Ставка.     \end{itemize}         \begin{tabular}{ccccc&lt;{\onslide&lt;2-&gt;}c&lt;{\onslide}c}             $p_1$ &amp; $p_2$ &amp; $\ldots$ &amp; $p_{9}$ &amp; $p_{10}$ &amp; $W$  &amp; $D$\\             $1$   &amp; $1$   &amp; $\ldots$ &amp; $1$      &amp; $1$     &amp; $w_1$&amp; $d_1$\\             $1$   &amp; $1$   &amp; $\ldots$ &amp; $1$      &amp; $0$     &amp; $w_2$&amp; $d_2$\\             $1$   &amp; $1$   &amp; $\ldots$ &amp; $0$      &amp; $1$     &amp; $w_3$&amp; $d_3$\\             $1$   &amp; $1$   &amp; $\ldots$ &amp; $0$      &amp; $0$     &amp; $w_4$&amp; $d_4$\\             $\vdots$ &amp; $\vdots$ &amp; $\vdots$ &amp; $\vdots$ &amp; $\vdots$ &amp; $\vdots$ &amp; $\vdots$\\             $0$   &amp; $0$   &amp; $\ldots$ &amp; $0$      &amp; $1$     &amp; $w_{1023}$&amp; $d_{1023}$\\             $1$   &amp; $1$   &amp; $\ldots$ &amp; $0$      &amp; $0$     &amp; $w_{1024}$&amp; $d_{1024}$         \end{tabular} \end{frame}   This produces 2 slides: the first one with p1, p2, ..., p9, p10 and D columns, and the second with W added, while I want them to appear in the following order:   1st slide: p1, p2, ..., p9, p10  2nd slide: p1, p2, ..., p9, p10, W 3rd slide: p1, p2, ..., p9, p10, W, D   I looked in the manual and found this example:  \begin{frame}     \begin{tabular}{l!{\vrule}c&lt;{\onslide&lt;2-&gt;}c&lt;{\onslide&lt;3-&gt;}c&lt;{\onslide&lt;4-&gt;}c&lt;{\onslide}c}     Class &amp; A &amp; B &amp; C &amp; D \\     217     X &amp; 1 &amp; 2 &amp; 3 &amp; 4 \\     Y &amp; 3 &amp; 4 &amp; 5 &amp; 6 \\     Z &amp; 5 &amp; 6 &amp; 7 &amp; 8     \end{tabular} \end{frame}   which does what is supposed to. However, I don't seem to be able to apply its logic to my problem. :( Is anyone willing to help?   P.S. What are the meanings of &lt; and ! in columns specification? Difference between staticmethod and classmethod Simplify $\arctan (\frac{1}{2}\tan (2A)) + \arctan (\cot (A)) + \arctan (\cot ^{3}(A)) $ How to simplify $$\arctan \left(\frac{1}{2}\tan (2A)\right) +  \arctan (\cot (A)) + \arctan (\cot ^{3}(A)) $$ for  $0&lt; A&lt; \pi /4$?  This is one of the problems in a book I'm using. It is actually an objective question , with 4 options given , so i just put $A=\pi /4$ (even though technically its disallowed as $0&lt; A&lt; \pi /4$) and got the answer as $\pi $ which was one of the options , so that must be the answer (and it is weirdly written in options as $4 \arctan (1) $ ).  Still , I'm not able to actually solve this problem. I know the formula for sum of three arctans , but it gets just too messy and looks hard to simplify and it is not obvious that the answer will be constant for all $0&lt; A&lt; \pi /4$. And I don't know of any other way to approach such problems. How long will foods that have "Best by: XX-XX-XX" on the product last past that date?  I have tried looking online, and all I can find is anecdotal evidence, which isn't very assuring for me since there seems to be no specific "x food will expire y weeks after its best by date".  Is there a rule of thumb or some guide out there that can tell me how long a "best by" food will last? Or is it safe to assume that they never expire, since it's not actually labelled on the product? Is there a single word for something that is simultaneously not interesting and not boring? I am looking for a word that would describe a concept or activity, such as playing a game X, that is1 neither boring nor interesting. In other words, it should mean ‘neutral’ wrt intrestingness (~ boringness) but still comparable on the scale of intrestingness to both ‘boring’ and ‘interesting’.  An example sentence would be  As far as I'm concerned, long-distance running is [insert word]; it is not boring but it's also not interesting.  Criteria2   Has to be unambiguous3, and may consist of two words at most. Has to be a single word. Should be formal in the sense that it is included in Cambridge Dictionary, or Merriam Webster, or both. Should not contain negating prefixes, such as ‘un-’.   Does such a word exist in the English language?  For readers' convenience, please state which criteria you believe your word suggestion has met. You may do so, e.g., by adding a disclaimer at the top or bottom of your answer. Simply writing (1., 2.) is sufficient.        1 Assume a ternary system of intrestingness.   2 If not all criteria can be met, you may relax  the requirements from bottom to top, in the following order: 4. -> 3.  -> 2. -> 1. Answers with the smallest number of relaxed criteria in this order will be preferred in accepting. For example, fulfilling  (1., 2., 3.) is better than achieving (1., 3., 4.). Situations where a  higher priority ordering fulfills fewer criteria than a lower priority  vector, such as (1.) vs (3.,  4.), will be assessed on a case-by-case  basis.   3 Words such as ‘unappealing’ thus even fail  criterium 1 because in a three-valued system ‘unappealing’ ~ ‘not  appealing’ ~ ‘not interesting’ can be taken to mean either ‘boring’ or  ‘neutral wrt intrestingness’. Terms for collections of animals As I watched the murder of crows sitting on the line above my house this evening, I got wondering where all of the collective nouns for animals (pod of whales, gaggle of geese, pride of lions) came from and why we need so many.    If sheep can be a flock, why can't whales, geese, lions, and crows? Google analytics: Tracking Not Installed