When I punch a wall, Why doesnt my fist go through instead of staying at rest on the wall? What is cancelling out the force of my punch?
If you've ever been annoyingly poked by a geek, you might be familiar with the semi-nerdy obnoxious response of      "I'm not actually touching you! The electrons in the atoms of my   skin are just getting really close to yours!"   Expanding on this a little bit, it seems the obnoxious geek is right. After all, consider Zeno's paradox. Every time you try to touch two objects together, you have to get them halfway there, then quarter-way, etc. In other words, there's always a infinitesimal distance in between the two objects.   Atoms don't "touch" each other; even the protons and neutrons in the nucleus of an atom aren't "touching" each other.  So what does it mean for two objects to touch each other?   Are atoms that join to form a molecule "touching"? I suppose the atoms are touching, because their is some overlap, but the subatomic particles are just whizzing around avoiding each other. If this is the case, should "touching" just be defined relative to some context? I.e, if I touch your hand, our hands are touching, but unless you pick up some of my DNA, the molecules in our hands aren't touching? And since the molecules aren't changing, the atoms aren't touching either?  Is there really no such thing as "touching"?
I Cancelled Microsoft 10 Reservation and uninstalled KB3035583 but Window 10 is still trying to install I cancelled the Microsoft Windows 10 Reservation and uninstalled KB3035583, but Windows 10 is still trying to install.   After I uninstalled KB3035583 and restarted my laptop as instructed, I could not find KB3035583 to hide it.   Now Windows 10 is sitting in my Windows Update saying that it will install when I restart my computer. How to make `cd dir/filename` take me to dir/? I would find it very convenient to be able to use cd with a file argument.  cd myDirectory/anyname.anyExtension would be equivalent to cd myDirectory/  What would be the best alias or function to achieve this behavior ?  EDIT: Sorry I didn't mention it in the 1st place: I use zsh What is the difference between the words which and that?  For example I have the following sentences:   “I have a car which is blue.” “I have a car that is blue.”   Are there any rules specifying usage of which and that? Proving that if $f: \mathbb{C} \to \mathbb{C} $ is a continuous function with $f^2, f^3$ analytic, then $f$ is also analytic Let $f: \mathbb{C} \to  \mathbb{C}$ be a continuous function such that $f^2$ and $f^3$ are both analytic. Prove that $f$ is also analytic.   Some ideas: At $z_0$ where $f^2$ is not $0$ , then $f^3$ and $f^2$ are analytic so $f = \frac{f^3}{f^2}$ is analytic at $z_0$ but at $z_0$ where $f^2$ is $0$, I'm not able to show that $f$ is analytic. How to study/prepare for the Salesforce Developer Certification I am fairly new to Force.com development (less than a year). I did not learn it from the ground up. So I think it will be good to study for the developer exam to strengthen my basics and improve my overall knowledge of Force.com + it will be great to have this certification.  Now it's surprising that there is not a lot of great information on the web about how to go about obtaining this certification. Most other major certifications have dedicated study guide books available but there are few for Force.com and I don't think any of them are official.   The official page has little information. The Study guide gives a broad description of the topics in the test.   I see a lot of the esteemed members are here certified developers. I think if you guys could give us a little information, hints/tips and some advice on how to prepare for this exam, it will really be of great help. Also is DEV401 required/helpful?  Also if we could get recommendations for great resources(books, online training etc) and practice tests it will be awesome. I'm trying to parse json response.. but keep getting this error      Invalid conversion from runtime type List ANY> to Map String,ANY>   Map&lt;String, Object&gt; MapLv3 = new Map&lt;String, Object&gt;();      Integer x2 = 0; for (Object oh : CallsList){     MapLv3.put(String.valueof(x2), oh);     x2++; } index = x2; System.debug('Map Lv 3 ==&gt;'+MapLv3);  Map&lt;String, Map &lt;String, Object&gt;&gt; Map3 = new Map&lt;String, Map &lt;String, Object&gt;&gt;(); for (Integer a2 = 0; a2 &lt; index; a2++){     Map3.put(String.valueof(a2),(Map&lt;String,Object&gt;) MapLv3.get(String.valueof(a2))); } System.debug('Segment ==&gt;'+Map3.get('0').get('segments')); I know that I have to use some tweaking tool and then a extension for this. But all extensions that are suggested for this(Workspace grid, Workspace matrix), aren't available in the software center. Windows of an application have minimum size and I can't find the window anymore I had an application (in case it matters: LibreOffice Calc] in full-size mode. I then clicked the middle of the three buttons of the top right to adjust the size. When I did that, the window became minimum size, literally a vertical line. I panicked and alt-tabbed, and now I can't even find the vertical line anymore. Opening new windows in that application opens all of them hidden to me, and closing/reopening or even restarting the OS doesn't help. I don't know how to resize my invisible windows anymore. Here's the preview of the windows in the application launcher: a vertical line (that I don't find on my screen anywhere if I click this). how to prove $\forall p$ prime :   $\binom{2p}{p} \equiv 2 \pmod p$ we have:  $\binom{2p}{p} = \frac{2p (2p-1)(2p-3)...1}{p!p!}$ but how to continue? Can a continuous function from the reals to the reals assume each value an even number of times? Possible Duplicate:          Both words seem to be used interchangeably. I generally don't differentiate between them and intuitively pick one over the other. Is there a standardized way to distinguish between the two? Book series about aliens who put "caps" on people to control them Why can rm remove read-only files? Details on how the Yearling badge works Jawa asked me this  and I didn't know the answer. So I present it to the meta SO community:     [To get the Yearling badge] Do you need to earn the 200 rep within that one year or is it enough to get 200 at some point after being a member for a year? And does 'a year' mean the very first 12 months or the last (sliding window of) 12 months?    I would assume that if you hit 200 reputation after you've already been around for a year, then you would get the Yearling badge. But I don't know. How many permutations of $\{1, \ldots, n\}$ exist such that none of them contain $(i, i+1)$ (as a sequence) for $i \in {1,...,(n-1)}$? Capturing speaker output in Java If votes works differently on meta sites how does that of accepting answers work? In the faq of meta sites you can read something like the following:     Voting here works a bit differently   from other Stack Exchange sites. On   Meta Stack Overflow, voting is used to   express agreement or disagreement, not   to point out a lack of quality or   helpfulness. Please don't be concerned   if you receive downvotes – members of   the community may simply disagree with   your bug, feature request, support   issue, or the nature of the   discussion.   My question is: If votes works differently on meta sites how does that of accepting answers work?  Take for instance a question on a meta site that is meant for the community to discuss some issue. What does it mean if the question is accepted? Accepting an answer is up to the author of the question so it cannot be a sign of what answer the community concludes from the discussion. It could mean that the discussion is over but that should be up to the community and not the author of the question. Is it so that accepting an answer for a discussion question on a meta site does not have a particular function? Reinhardt's main strength is his shielding abilities and the protection he provides for his team, but Are there any abilities that cannot be blocked by Reinhardt's barrier field? Creation and annihilation operators in the hydrogen atom How can I install Ubuntu without CD and USB? I want to install Ubuntu on my laptop that doesn't have a CD-ROM drive and I have no spare USB disk. I've tried Wubi, but that doesn't seem to work (since it prompts me to have the CD in the drive, which I don't have).  How can I install Ubuntu, easily and in a fast way?  P.s: I want to dual boot it with Windows 7 (which was preinstalled).  Edit:   When extracting the ISO to a folder and running Wubi it does install, but when I reboot the computer, it doesn't show GRUB, nor can I choose if I want to boot Ubuntu or Windows 7. After trying for the third time today, wubi gives me an error: Permission denied   I'm the administrator on the PC.