Is better to say the e.g. kinetic energy is 0 joule or kinetic energy is 0 ? since 0*joule equals 0.Is a mathematical concept behind because in many books i find both ways.
Is $0 \, \mathrm m = 0 \, \mathrm s = 0 \,\mathrm {kg} = 0$? How do we define $[0 \, \mathrm m]$?  I once was given an assignment where I was asked to deduce and write down some physical quantity. It turned out that this quantity was $0$ in one unit or another, so I decided to drop the physical units because I figured that it didn't matter anyhow.  But I got to thinking:  If $0 \, \mathrm m = 0$, then we could add units of different dimensions (an operation not normally defined) like so: $5 + 0 \,\mathrm m = 5$.   Does $[ \cdot ]$ map $0 \, \mathrm m$ to both $0$ and $L$? Is there an established regime of thinking about physical quantities as an abstract algebra? Perhaps as a vector space where formal sums such as $5 \, \mathrm m + 10 \, \mathrm s$ are allowed? Would it be improper to drop the units of measurement of $0 \,\mathrm m$ like this in an academic paper?
How to boot Ubuntu persistent live USB on Android? I'm discovering the possibilities offered by persistent live USB using Ubuntu 19.10 and I was wondering if it would be possible to boot with Ubuntu on Android (i.e. using your computer capabilities through your smartphone) using those multi-plug USB sticks which have both USB3 and micro-USB2.  In other way: can I get some kind of a boot menu on an Android device in order to boot with a persistent live USB in order to access my Linux computer tools and setup from a wider range of devices? I have the Basic license for ArcGIS and so I cannot use the collapse dual lines to centreline tool or the river bathymetry toolset by ESSA as they both need an advanced license.   Any idea how I can find the centreline or thalweg of the canyons using another tool which works in the standard version of ArcGIS please? On the one side, the USA is just one country. Logic says it should be, then, singular, just like the United Kingdom is. Example:     The USA owns this domain.   On the other side, if I however expand "the USA" to "the United States of America", I'd tend towards using plural &mdash; the noun the verb agrees with, "States," is definitely plural. Example:     The United States of America own this domain. → The USA own this domain.   What form should I prefer? Are there any known uncountable transfinite increasing sequences of real numbers? The real numbers are uncountable, so assuming the axiom of choice there is at least transfinite sequence of real numbers $r_0, r_1, r_2, ..., r_\omega, r_{\omega + 1}, ..., $ up to (and possibly including) $r_{\omega_1}$ that contains an uncountable number of terms. However, it's not guaranteed that $r_0 &lt; r_1 &lt; ..., r_\omega &lt; ...$  Is there a known transfinite sequence of real numbers that is monotonically increasing and which contains uncountably many real numbers?  Thanks! Zooming to selection in arcpy.mapping and only seeing selected features? I selected data by using select layer by attribute, then I need to only select these selection and zoom in to the selection.  my code is this, it can zoom in base on the scale I set, but I see other adjacent polygon that has other Code_No, why?  Layer = arcpy.mapping.ListLayers(mxd, "lyr", df)        arcpy.SelectLayerByAttribute_management(lyr, "NEW_SELECTION", "Code_NO = '%s'"%mycodeNo)            df.extent = lyrLayer1.getSelectedExtent() df.scale *= 2 I already know how to do it on Mac OS X (plenty of instructions online).  But is it possible to do it on Ubuntu? If yes, how? Two  have been announced in LoL.  They have an ability that makes them be able to recall together.                                  What are the limits to this ability? Can the 'non-recaller' jump in at the last second and get some kind of instant recall?  Can somebody with the setup to get on PBE test it and tell us what are the limitations of this ability? Why can't a Federation Starship's transporter history be used to bring someone back to life? When functions commute under composition Is there anyway to sync Outlook's calendar with Google's calendar? I've tried  before but it doesn't work properly. I'm using Windows 7 and Outlook 2010.  The thing is, it's really easy to check my Google Calendar on my phone since I have an Android terminal, but on my computer I prefer just opening Outlook instead of opening a web browser and logging into Gmail. Summarizing flatness of county with statistic Elevation variance per square mile I need to classify every county in the US as either hilly, moderately hilly, or flat. Accuracy is not critical, just a rough classification. I used R and followed the advice in  answer to import elevation and counties and calculated the zonal variance. This was inherently biased towards larger counties since they have more surface for hills, so I need to divide by area. If I divide variance by square miles does that reasonably represent hilliness? The preliminary results seem decent, with the highest values being places like Colorado, Hawaii, Montana, etc. On several occasions, I was reading a question thinking "I know a guy that knows the answer to this" and that guy (or gal) also happens to be a registered user. How can I bring this to the attention of this user? I use TeX Live 2010 and my editor is Texmaker Bidi. It was working probably good but from 2 months ago I've encountered with the error:   !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ! ! Fatal fontspec error: "cannot-use-pdftex" !  ! The fontspec package requires either XeTeX or LuaTeX to function. !  ! You must change your typesetting engine to, e.g., "xelatex" or "lualatex" ! instead of plain "latex" or "pdflatex". !  ! See the fontspec documentation for further information. !  ! For immediate help type H &lt;return&gt;. !...............................................   when I'm trying to load xepersian LaTeX.  but I do not know how can I change pdfLaTeX to XeLaTeX.    This is the second edit of my question .   the code is :    ‎\documentclass{article}‎ ‎\usepackage{pstricks}‎ ‎\usepackage{‎pst‎-‎bezier}‎ ‎‎\usepackage{xepersian}‎  ‎\settextfont{XB Zar}‎  ‎\setlatintextfont{Junicode}‎  ‎\setdigitfont{XB Zar}‎  ‎\begin{document}‎  ‎!‎سلام دنیا‎‎ ‎\begin{pspicture}(‎3‎,3)‎ ‎\psbcurve(1,2)(5,7)(2,2)(12,3)‎ ‎\end{pspicture}‎ ‎ ‎\end{document}   but the output does not include the shapes . How do I get my arrow keys working in the at> prompt Transit in LA after 90 days in North America under VWP/ESTA I am from NZ and have spent 90 days in the USA with an ESTA visa waiver, and I am going to Canada before returning to NZ. My return flight is from LA but I have already used my 90 days of my ESTA and have not technically 'left' North America (Canada apparently doesn't count). My question is, how do I catch my return flight from LA? Can I get another ESTA even though I haven't left North America? How was the bank robbery completed? In Now You See Me, when Morgan Freeman explains to the detective on how the Four Horseman robbed the bank, he mentions that they replaced the real money (while in the secured transport truck) with flash paper.  This does not explain how the paper in the bank got ignited, and no ignition/stimulator left in the scene as evidence.  Who/What/When ignited the flash paper in the bank on time?   There had to be some timer/delay mechanism on the platform, or something similar - but in the frames we see - there is nothing. Let X be a T1 space, and show that X is normal if and only if each neighbourhood of a closed set F contains the closure of some neighbourhood of F Let $X$ be a $T_1$-space, and show that $X$ is normal if and only if each neighbourhood of a closed set $F$ contains the closure of some neighbourhood of $F$.  I saw this statement in the book Introduction to topology and modern analysis by Simmons. I tried to prove it but I did not get any where. How may it be proved? Python inheritance - how to disable a function In C++ you can disable a function in parent's class by declaring it as private in the child class. How can this be done in Python? I.E. How can I hide parent's function from child's public interface? I know that $re^{i\theta} = x + iy$ for any complex number $x + iy$ by Euler's formula. How do you calculate relative and global phase? Determine the number of ways to colour a 1 by n grid using the colours red and white if an even number of squares are to be coloured red.