I know (but am quite confused) that static friction is greater than kinetic friction, but is this only true when the object is at rest/stationary? Please explain about this in detail while referring to the measure/amount of static friction and the kinetic friction with an example too if possible
When dragging an object, there is a greater start-up force than the force it takes to keep it moving. Why is this? Why are there two different values for friction?
How to get the list of properties of a class? As of patch 1.5, I am completely unable to see underwater in Skyrim.  It's not even that it's murky or dark - it's just a solid grey or green screen.  I can still skim across the surface and see into deep waters, but if I go any deeper than that, nothing is visible.  I can still access items like chests underwater if I figure out their location first (by skimming across the surface) and then point my character there and hope really hard that it gets me to the right place.  I was never able to see much underwater, but I at least used to be able to see small things like wood floating near a shipwreck.  Now, there's just nothing. I am running the Steam version of Skyrim with graphics on Ultra High, with the high res textures DLC.  I've tried disabling the high res textures (along with all my other mods) and it still happens.  In case it's relevant, my GPU is a GTX 560 Ti.  Does anyone have any solutions to this? Get text from pressed button If $\int_0^x f \ dm$ is zero everywhere then $f$ is zero almost everywhere I have been thinking on and off about a problem for some time now. It is inspired by an exam problem which I solved but I wanted to find an alternative solution. The object was to prove that some sequence of functions converges weakly to zero in $L^2$.   I managed to show (with some help) that the limit $f$ (of a subsequence) satisfies $\int_0^x f \ dm=0$ for all $x&gt;0 $. From this I want to conclude that $f=0$ a.e. I can do this with the fundamental theorem of calculus in its Lebesgue version but there ought to be a more elementary proof.  Can someone here help me out? This is a  about Hosting multiple SSL websites on the same IP.   I was under the impression that each SSL Certificate required it's own unique IP Address/Port combination. But the  is at odds with this claim.  Using information from that Question, I was able to get multiple SSL certificates to work on the same IP address and on port 443. I am very confused as to why this works given the assumption above and reinforced by others that each SSL domain website on the same server requires its own IP/Port.  I am suspicious that I did something wrong.  Can multiple SSL Certificates be used this way? Is there a formal proof for the superposition theorem? "He needn't say" / "He doesn't need to say" When I studied English at school (in Italy, more than 35 years ago), we were taught a rule according to which one should say, e. g., "He needn't (need not) say", but NOT "He doesn't need to say".  If I'm not mistaken, it was explained to us that the rule holds good with the following limitations:  1) only in the negative form: thus, "He needn't say", but "He needs to say", and "Does he need to say?";  2) only in the present tense: thus, "He needn't say", but "He didn't (won't, wouldn't, etc.) need to say";  3) only when an infinitive follows: thus, "He needn't see a doctor", but "He doesn't need a doctor".  But, if I google "doesn't need to", I find 125,000,000 occurrences.  I was wondering: does the rule hold good more for British than for American English?  Also, perhaps it isn't an absolute rule, and both constructions ("He needn't say" and "He doesn't need to say") are possible.  Is the rule at least a good description of the circumstances when we CAN (but needn't necessarily) use this construction?  Thank you very much, for this and the other answers. Is there a way for me to download the full list of tags (and synonyms) used on Stack Overflow? My intent is to import these tags into an SQLite database as part of a process to convert all of my delicious bookmarks and tags to the ones used here on Stack Overflow. Test whether a glob has any matches in bash What is Skynet's ultimate goal after defeating the resistance? According to , weight decay (regularization) is not usually applied to the bias terms b why?  What is significance (intuition) behind it? I just wanted to make some input where I press a key and the auto-repeat function engages so I don't have to press the 0 key many times to make a long number.  10000000000000000000000000000  This has always worked without fail in the past, but it's not something I do often and I'm not sure where to look next to figure out what might be preventing this.     I've toggled the sliders to change the delay for key repeat, but the only thing I can hang my hat on is that perhaps Lion disables this with the new feature where you hold down some keys (like the vowels, but also some consonants) to get alternate accented characters.  s turns into ß or ś or š and so on....  Am I missing an obvious setting, or is this something that has moved to a hidden setting or is simply a bug that these controls are still around since key repeat is now deprecated?  Comments welcome if anyone doesn't have an answer, but can provide specifics where this does work for them. I've checked two Macs so I'm guessing it's not related to keyboard type or connection method. I file 83(b) election, but did't include a copy of it in that year’s tax return If a ring element is right-invertible, but not left-invertible, then it has infinitely many right-inverses. I have to resit a calculus exam and for some reason set proofs were never my best friend...  Anyway, on a practice exam I encountered the following proof:  $$A\cap(B\cup C) = (A\cap B)\cup(A\cap C)$$  When I draw a Venn-diagram it seems quite obvious but I couldn't manage to write the proof down properly.  If someone could help me, that'd be great! Why did Obi-Wan allow Leia to get adopted by such a high profile figure? How to find $\partial\chi^2/\partial a$ where $\chi^2=\sum_{i=1}^N\dfrac{D(x_i)-a-b(x_i)^2}{\sigma_i^2}$?  My attempt: \begin{align} \dfrac{\partial}{\partial a}\sum_{i=1}^N\dfrac{D(x_i)-a-b(x_i)^2}{\sigma_i^2} &amp;= \dfrac{\partial}{\partial a}\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\sum_{i=1}^N\dfrac{-a}{\sigma_i^2}\\ &amp;=\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\dfrac{\partial}{\partial a}\sum_{i=1}^N\dfrac{-a}{\sigma_i^2}\\ &amp;=\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\dfrac{1}{\sigma_i^2}\cdot\dfrac{\partial}{\partial a}\sum_{i=1}^N-a\\ &amp;=\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\dfrac{1}{\sigma_i^2}\cdot\dfrac{\partial}{\partial a}a^N\\ &amp;=\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\dfrac{1}{\sigma_i^2}\cdot N\cdot a^{N-1}\\ \end{align}  Is this correct?  EDIT: As per the accepted answer, this is how I got my final partial derivative. \begin{align}             \dfrac{\partial}{\partial a}\sum_{i=1}^N\dfrac{D(x_i)-a-b(x_i)^2}{\sigma_i^2} &amp;= \dfrac{\partial}{\partial a}\Bigg[\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}-\sum_{i=1}^N\dfrac{-a}{\sigma_i^2}\Bigg]\\             &amp;=\dfrac{\partial}{\partial a}\Bigg[\sum_{i=1}^N\dfrac{D(x_i)-b(x_i)^2}{\sigma_i^2}\Bigg]-\dfrac{\partial}{\partial a}\Bigg[\sum_{i=1}^N\dfrac{-a}{\sigma_i^2}\Bigg]\\             &amp;= 0-\dfrac{\partial}{\partial a}\Bigg[\dfrac{-a}{\sigma_1^2}+\dfrac{-a}{\sigma_2^2}+\cdots+\dfrac{-a}{\sigma_N^2}\Bigg]\\             &amp;= -\Bigg[\dfrac{\partial}{\partial a}\Bigg[\dfrac{-a}{\sigma_1^2}\Bigg]+\dfrac{\partial}{\partial a}\Bigg[\dfrac{-a}{\sigma_2^2}\Bigg]+\cdots+\dfrac{\partial}{\partial a}\Bigg[\dfrac{-a}{\sigma_N^2}\Bigg]\Bigg]\\             &amp;= -\Bigg[\dfrac{-1}{\sigma_1^2}\cdot\dfrac{\partial}{\partial a}[a]+\dfrac{-1}{\sigma_1^2}\cdot\dfrac{\partial}{\partial a}[a]+\cdots+\dfrac{-1}{\sigma_N^2}\cdot\dfrac{\partial}{\partial a}[a]\Bigg]\\             &amp;= -\Bigg[\dfrac{-1}{\sigma_1^2}+\dfrac{-1}{\sigma_2^2}+\cdots+\dfrac{-1}{\sigma_N^2}\Bigg]\\             &amp;= \sum_{i=1}^{N}\dfrac{1}{\sigma_i^2}\\         \end{align} What would be better practice when giving a function the original variable to work with:  unsigned long x = 4;  void func1(unsigned long&amp; val) {      val = 5;             } func1(x);   or:  void func2(unsigned long* val) {      *val = 5; } func2(&amp;x);   IOW: Is there any reason to pick one over another? How to Hide sections of InfoPath form based on Group membership I need to Hide "Sections" of InfoPath form using SharePoint or AD group membership (either is fine). How can I achieve this?  InfoPath 2010 in SharePoint 2010 Does anyone have a recommendation for a book to use for the self study of real analysis? Several years ago when I completed about half a semester of Real Analysis I, the instructor used "Introduction to Analysis" by Gaughan.   While it's a good book, I'm not sure it's suited for self study by itself.  I know it's a rigorous subject, but I'd like to try and find something that "dumbs down" the material a bit, then between the two books I might be able to make some headway.