This question has been asked many a times on physics stack exchange but I can't understand this in simple terms. This is a definition I got online:  The third law states that all forces between two objects exist in equal magnitude and opposite direction: if one object $A$ exerts a force $F_A$ on a second object $B$, then $B$ simultaneously exerts a force $F_B$ on $A$, and the two forces are equal in magnitude and opposite in direction: $F_A = −F_B$.  My question for this is that if a force is applied to body $B$ by body $A$, and the magnitude is $10$N, body $B$ is applying the same magnitude of force against body $A$. So, the forces should cancel out and motion won't be possible in that case as Newton's first law states that there should be an unbalanced force for bringing a body from rest to motion. One thing people are answering is that they are on different body but they are also in different direction so force should cancel out as it is simultaneously exerted on the two bodies.
Given Newton's third law, why is there motion at all? Should not all forces even themselves out, so nothing moves at all? When I push a table using my finger, the table applies the same force onto my finger like my finger does on the table just with an opposing direction, nothing happens except that I feel the opposing force. But why can I push a box on a table by applying force ($F=ma$) on one side, obviously outbalancing the force the box has on my finger and at the same time outbalancing the friction the box has on the table? I obviously have the greater mass and acceleration as for example the matchbox on the table and thusly I can move it, but shouldn't the third law prevent that from even happening? Shouldn't the matchbox just accommodate to said force and applying the same force to me in opposing direction?
How do I sort custom objects alphabetically in an array in Java? How do I move all files from one folder to another using the command line? What does "proverbial" mean? This question is essentially the same as one of my , except the only difference is that I am using "only" to change the text at the same location (i.e., ). In other words, I am destroying my earlier text as I go, and not adding new ones underneath the previous ones.   Since the text for the first "only" is shorter than the second "only", therefore the image will shift location. I would like for the image to remain at its location.   Here is an example     it may not be obvious but the second image is higher up than the first.  The code is here, can someone find a solution?  \documentclass{beamer}  \usepackage{graphicx}  \title[Title]{Presentation} \author{Sandro Botticelli} \institute{Italy} \date{1484}  \begin{document}   \begin{frame} \begin{figure} \includegraphics[scale = 0.8]{Venus}     \caption{Nascita di Venere} \end{figure}  \only&lt;1&gt;{In the centre the newly-born goddess Venus stands nude in a giant scallop shell. Its size is purely imaginary, and is also found in classical depictions of the subject. }    \only&lt;2&gt;{Alternative identifications for the two secondary female figures involve those also found in the Primavera; the nymph held by Zephyr may be Chloris, a flower nymph he married in some versions of her story, and the figure on land may be Flora. Flora is generally the Roman equivalent of the Greek Chloris; in the Primavera Chloris is transformed into the figure of Flora next to her, following Ovid's Fasti, but it is hard to see that such a transformation is envisaged here.} \end{frame}   \end{document} Show the series $a_n/(1+a_n)$ converges absolutely Why can't I use a type argument in a type parameter with multiple bounds? So, I understand that the following doesn't work, but why doesn't it work?  interface Adapter&lt;E&gt; {}  class Adaptulator&lt;I&gt; {     &lt;E, A extends I &amp; Adapter&lt;E&gt;&gt; void add(Class&lt;E&gt; extl, Class&lt;A&gt; intl) {         addAdapterFactory(new AdapterFactory&lt;E, A&gt;(extl, intl));     } }   The add() method gives me a compile error, "Cannot specify any additional bound Adapter&lt;E&gt; when first bound is a type parameter" (in Eclipse), or "Type parameter cannot be followed by other bounds" (in IDEA), take your pick.  Clearly you're just Not Allowed to use the type parameter I there, before the &amp;, and that's that. (And before you ask, it doesn't work if you switch 'em, because there's no guarantee that I isn't a concrete class.) But why not? I've looked through Angelika Langer's FAQ and can't find an answer.  Generally when some generics limitation seems arbitrary, it's because you've created a situation where the type system can't actually enforce correctness. But I don't see what case would break what I'm trying to do here. I'd say maybe it has something to do with method dispatch after type erasure, but there's only one add() method, so it's not like there's any ambiguity...  Can someone demonstrate the problem for me? How can I reliably get the operating system's name? Say I am logged into a remote system, how can I know what it's running? On most modern Linuxes (Linuces?), you have the lsb_release command:  $ lsb_release -ic     Distributor ID: LinuxMint Codename:       debian   Which as far as I can tell just gives the same info as /etc/lsb-release. What if that file is not present? I seem to recall that the lsb_release command is relatively new so what if I have to get the OS of an older system?  In any case, lsb stands for Linux Standard Base so I am assuming it won't work on non-Linux Unices. As far as I know, there is no way of getting this information from uname so how can I get this on systems that do not use lsb_release? Is there any problem if the last name prints first than the first name on an air ticket? Is there any problem if the last name prints first then the first name in international air ticket? With Bash's source it is possible to execute a script without an execution bit set. This is documented and expected behaviour, but isn't this against the use of an execution bit?  I know, that source doesn't create a subshell. Using the Well Ordering Principle to Show that n^3 - n is divisible by 6. I read the following two sources and I think I understand the structure of proofs involving WOP, but I am stuck on the open-ended part where you prove P(n-1) for the  following problem:    Use the well-ordering principle to show that n^3 - n is divisible by 6.    Any help would be greatly appreciated!   Note: After factoring out (n-1)^3 - (n-1) it took the form of n^3 - 3n^2 + 2n and the only difference between that and n^3 - n is "3n^2 - 3n" which I proved was divisible by 6 via induction. Is there a better way to solve this problem?  Edit: , post is useful however I not supposed to use induction for the main part of the proof. Hiding reputation and encouraging thinking time would improve the quality of answers on SO I've only been a member of SO for a couple of months but I must say that the site can be a bit daunting even for an experienced developer.  Part of this is because when users with very high reputations answer questions then it seems that everyone assumes that they have the right answer.  I don't want to go into the self-fulfilling nature of reputation increase for high reputation people.  But I think it is clear that people with high reputation scores get more upvotes () because people assume (usually accurately) that they are correct.    But if reputation was hidden on SO, at least for, say, the first hour after a question is asked then the probability of the best answer being upvoted the most would surely increase.  This might also require the hiding of the names of the answerers if they have very high reps!  As a second method of getting improved answers I would correlate the value of an answer (in terms of reputation gained) with the difficulty of the question.  And the simplest way to do that would be based on the time required for the question to be answered.  So if a question is answered within a minute then it is a 20% question (2 points per upvote), within 2 minutes a 40% question, within 5 minutes a 60% question and so on, on to say a 200% answer (20 points per upvote) on questions that have been hanging around for months.  This would encourage considered answers to new questions and tempt people into reducing the backlog - rather than encouraging people to sit on the 'newest questions' hoping for a gimme.  These two measures would incentivise people to answer the questions that no-one likes the look of and reduce the relative value of answering easy questions. Is it acceptable to insult god in a user profile? Like always I hang around in Stack Overflow's chatrooms. Today, someone posted a link to his new "reloaded" user profile.  Along the lines I read in Arabic "god is a pig". So I asked him to remove it:     Me: I have a lot of respect towards you because of your knowledge but what you wrote there in Arabic is offensive. Could you remove it please?   OP: if it were in English, would it be equally offensive?   I will write it in Dutch because you ask it so kindly.   Me: yeah, I mean what's your goal? You're just seeding hatred   OP: It is an experiment.   After that, the user changed it to Dutch.  My question is: are such statements acceptable by Stack Exchange's standards? If not, should I flag one of his posts like stated ? If yes, could you state why?  My answers to possible questions:   This happened on SO, why don't you post it on MSO?   This happened on SO but I think it's applicable to all SE sites.  Why didn't you link the user or the chat conversation?   I want the user to remain anonymous unless he or she chooses to reveal him/her self. I will give the user a link to this question  Why do you care?   I find it offensive, not only to my religion but to any religion that believes in god. I posted this question to know what you guys and girls think about this. I live by the rules, so if it's acceptable by SE then so be it and I won't bother you again.  If you don't like it then move on.   I know that this is not a mosque/church/temple and that swearing  to a certain degree. But I don't see the point in insulting god, a religion or a race in a public profile. More over, it's not even built on arguments. How does negation affect the use and understanding of "or" and "and" I'm trying to make more sense of how negation effects how a sentence is parsed and understood if and's and or's are used within them.  Pop quiz: You are trapped on a bus with a bomb going 50 MPH. You have a radio... (okay enough Keanu Reeves references) :-)  Let's say the bomb expert says "Don't cut the red or green wires." I think that means "Do not cut the wires colored red. Do not cut the wires colored green."  Now, let's say the bomb expert said on the radio "Do not cut the red and green wires", instead. Do I take that to mean:     "Do not cut the wires colored red. Do not cut the wires colored green."   OR     "Do not cut the wires whose insulation has red and green stripes." ?   OR     "It's okay to cut the wires colored red or the wires colored green, as long I don't cut one of each color."   Which meaning should I take if the radio breaks and I can't ask follow up questions? Last night, I migrated my MacBook's operating system from 10.10 "Yosemite" to 10.11 "El Capitan". Everything seemed to go smoothly. Happily, regarding my TeX-related work, I am able to use the GUI front ends "TeXworks" and "TeXshop" just fine since completing the OS upgrade. I use MacTeX2015, with all the latest updates installed.  Oddly, though, since completing the upgrade I can no longer run any MacTeX command-line utilities such as texdoc and kpsewhich. (Actually, as I just discovered, I can no longer run pdflatex either from a command line. However, I never do run pdflatex from a command line prompt, so that's not an urgent problem for me -- at least not for now.)  The suggestions given in the posting  do not seem to be applicable to this case, as they all seem to revolve around setting up /usr/texbin correctly -- /usr/texbin is no longer allowed under MacOSX 10.11. The document  by Herb Schulz deals in depth with adjusting settings in the GUI front ends, but it appears not to touch on what to do about /usr/texbin, which appears to be the now-missing link to TeX's command line utilities.   Pointers and solutions most welcome! How do I go about proving this? I know one method is:  $\eqalign{    \cos (90^\circ + \theta ) &amp;\equiv \cos90^\circ \cos\theta  - \sin90^\circ \sin\theta   \cr    &amp;  \equiv (0)(\cos\theta ) - (1)(\sin \theta )  \cr    &amp;  \equiv  - \sin \theta  \cr} $  I'd appreciate others, particularly ones that will allow me to visualize this identity on the unit circle.  Thanks alot. Book or web site resources for an absolute beginner to learn about stocks and investing? I'm completely new to the world of investing and stocks. Knowing that I shouldn't invest or buy stocks until I know it well enough, I was wondering which cheap or affordable resources would be the best to get started?  I've seen quite a lot of books and websites that teach investing, but it's hard to choose.  To narrow it down, what book and/or what website would you recommend that does a good job teaching investing in stocks to beginners? Numbering equations If I am writing a LaTeX document on TexMaker and I want to number my equation but most probably I will be adding details later on and I do not want to fall into retyping it all over again. So if for example I have an equation and currently called equation (1.2) that I want to refer later as in the following sentence "As you can see in (1.2)" but then I had to edit my document in a way that it becomes (1.3) now instead of (1.2) what should I do in order to avoid editing large number of equations and my reference to them? How do you find out the caller function in JavaScript? function main() {    Hello(); }  function Hello() {   // How do you find out the caller function is 'main'? }   Is there a way to find out the call stack? Why would layout_width="wrap_content" take up the entire width of the screen? Can I achieve a torchlight effect (lighter area around a light source) in a 2D game? I am thinking of writing myself a simple 2D game. It will not shine with perfect graphics or gameplay at first, but I'd consider it my first step in PC game development. So, imagine such simple sprite-based 2D game (like Heroes IV or Startcraft BroodWar).  I want the gameplay to support day/night with the according lighting changes and at the same time it will be madness to have to create sprites for every lighting nuance. So, I decided adding a semi-transparent layer on top of other objects will be enough.   The issue with this solution is if I have a light source object in the game (like the hero wearing a torch, or a burning building), there must be a lighter area around it, right? Since I am putting my semi-transparent layer over everything, how would you suggest to achive the torchligt visual effect I want? Maybe redraw that layer adding 'gaps' or differently colored areas based on the lighting effect?