Let us consider block of mass $m$ hanging by rope with force $T$. When no other horizontal and vertical forces are acting on a block, the block is at equilibrium if $$T=mg.$$ And if the rope is pulled up a distance $h$, $$\text{work done}=mgh$$  Don't we need more force to move the block upward? If we just use $T$, the body will be in equilibrium. Don't we need more force to lift the block?
Consider there is a box of mass $m$ at rest on the floor. Most books give an example that we need to do a work of $mgh$ to lift the box $h$ upward.  If we analyze this work done, the external force acting on the box by us should be equal to the weight of the box. Therefore the net force is zero which in turn there is no acceleration. If there is no acceleration and the initial velocity of the box is also zero, how can the box move upward?
URLs are linked despite being inside a code span Last night I took some night sky shots, and I've noticed that with long exposure times (15s, 30s) the time it took to store the images in the camera memory card (jpeg) took roughly as long?  The actual file size is fairly small at 1 to 3MB per file.  Any idea why this is? How to check if a point is inside a rectangle? Awaken monit daemon every few hours for all monitored processes Label callouts in QGIS Has anyone been using callout labelling with QGIS, either trunk or stable?   Used for clustered points. That means the point stays where it is, the label maybe moved if required and a leader (plain or pointed) shows the linkage between the label and the point.   How could I do it (you know what I mean, no coding....)? Lower bounds for ${{2n} \choose {n}}$ What are common lower bounds for ${{2n} \choose {n}}$?    Edit:  I made a mistake in my original question.  It doesn't change my question but there is no reason for me to include the mistake. Can I install any iOS version I wish by picking and choosing which firmware to restore? I'm trying to downgrade my iPhone from the current iOS to an older one, as per .  But every time I try, I always receive this error:     The iPhone could not be restored. This device isn't eligible for the requested build.     I have tried many times with and without DFU mode. Any ideas regarding this? How to avoid noisy renders in Cycles? Why didn't Kenobi start training Luke earlier? When Anakin was only 9 years old, everyone in the Jedi Council was arguing that he was already too old for Jedi training.  When it comes to Luke, it was a pre-planned agenda to make him a powerful Jedi. So, why did Kenobi wait for Luke to be much older? He could have started Luke's training by himself. What does "proverbial" mean? Is it possible to install Office 365 (2013) on Ubuntu 15.04 Vivid Vervet? I would like to install Office 2015/365 on Ubuntu 15.04. I tried to install Office using Wine, but that did not work. Please note that I do not want virtualisation unless it has a -like behaviour, where application windows are treated like regular Ubuntu application windows by the system. How to find original community description Before joining a community you can easily see the community description. For example, for example before joining the Programming Puzzles &amp; Code Golf Stack Exchange you see the description:     Programming Puzzles &amp; Code Golf Stack Exchange is a question and   answer site for programming puzzle enthusiasts and code golfers.   However, after joining I can no longer see this description. I can go to the on-topic page and see a different description:     Programming Puzzles &amp; Code Golf is for programming contests and   challenges. We welcome questions from beginners and experts alike.   Yet, I cannot seem to find the original description anywhere. Is there a way to find the original description while being logged into a Stack Exchange site?  Based on Rene's answer, I can click the Tour link on each site, but StackOverflow (and maybe other sites) do not have a tour link. Instead, I'd have to go there by manually typing it in the address bar. Is there a reason that this has been removed from the Stack Overflow page? I'm running an Ubuntu 14.04 and want to install the Eclipse IDE for both Java and C/C++ programming. I installed the separate installation files from their official website. I followed this thread . (The top answer)   The steps helped me install the Java IDE but I don't know what changes I should make to the procedure to install the C/C++ IDE.   Another thread , recommended to install eclipse-cdt but the Eclipse version installed is outdated. (Doesn't allow me to install Pydev)   I have TWO questions:   Can the C/C++ libraries be downloaded from within eclipse, like Pydev? If not, how do I install both IDEs without interfering with each other?   P.S. I commented this query in the first thread but got no reply, that is why I'm asking a fresh question! I am getting a warning when trying to include the .net 3.5 sp1 prerequisite for my setup project.  The warning states Prerequisite could not found for bootstrapping.  Any suggestions?  Thanks Web sites can contain JPEG, GIF,PNG, SVG format graphics. Which ones should be used, and when? Username and Password not recognized when logging into Minecraft I am using an USB port as a power supply. Is there a way I can take the weak 5V of a regular laptop USB and transform if to 100V+ while begin in the smallest package possible. I've heard of boost converters but they are usualy too big. I want something that has the size of like a normal USB key.   What I want to do is to charge up around 5 capacitors at 100+V and then discharge them later. Power efficiency not a concern for me.  It would be helpful to include a schematic of the circuit. I'm working through Knuth's Metafont Book as preparation for learning Metapost and I'm running into some problems working through his "experiments".  I've installed the latest TeX Live 2013 distribution on my system but I'm having problems.  Here's the code (contained in file io.mf as recommended by Knuth):  mode_setup;  em#:=10pt#; cap#:=7pt#;  thin#:=1/3pt#; thick#:=5/6pt#;  o#:=1/5pt#; define_pixels(em,cap); define_blacker_pixels(thin,thick); define_corrected_pixels(o);  curve_sidebar=round 1/18em; beginchar("O", 0.8em#, cap#, 0); "The letter O";  penpos1(thick,10); penpos2(.1[thin,thick],90-10);  penpos3(thick,180+10); penpos4(thin,270-10);  x1l=w-x3l=curve_sidebar; x2=x4=.5w;  y1=.49h; y2l=-o; y3=.51h; y4l=h+o;  penstroke z1e{down}..z2e{right}             ..z3e{up}..z4e{left}..cycle;  penlabels(1,2,3,4); endchar;   Now, when running the mf command and loading this file, I get a window that is unfortunately empty.  Supposedly a large letter "O" should appear.  $ mf This is METAFONT, Version 2.718281 (TeX Live 2013) **io (io.mf The letter O [79]) *end Output written on io.2602gf (1 character, 1724 bytes). Transcript written on io.log.  $ gftodvi io.2602gf  gftodvi: fatal: tfm file `gray.tfm' not found.   Then, when trying to use the gftodvi command I get the above error.   Any ideas why my "window" that should display the letter "O" is blank/empty? How do I resolve the gray.tfm error? Are the two related?   Note: I'm using Ubuntu 14.04, but the TeXLive installation is NOT from the Ubuntu repository.  I used the installer from  and created a local "portable" installation. Find $\,\lim_{x\to 1}\frac{\sqrt[n]{x}-1}{\sqrt[m]{x}-1}$ Here is an interesting piece of code that my fellow team members were just having a slightly heated discussion about...    Dim fred As Integer    If True Then fred = 5 : fred = 3 : fred = 6 Else fred = 4 : fred = 2 : fred = 1   After executing the above code snippet, what is the value of fred?  Try not to cheat and debug the code.  This is a highly contrived code example that started out as an example of using the colon with an If statement, but then someone decided to take it upon themselves to proffer a result for fred.  UPDATE: I would not normally write code like this and this snippet only serves as an example. As it so happens, this question originated from a discussion involving the creation of a coding standards document for our team.