Force is generally a function of $\mathbf{x}$, $\mathbf{v}$ (or $\mathbf{p}$) and $t$
What is function of force $F$ and work $W$?
How do I make a textbox that only accepts numbers? I have a windows forms app with a textbox control that I want to only accept integer values. In the past I've done this kind of validation by overloading the KeyPress event and just removing characters which didn't fit the specification. I've looked at the MaskedTextBox control but I'd like a more general solution that could work with perhaps a regular expression, or depend on the values of other controls.  Ideally this would behave such that pressing a non numeric character would either produce no result or immediately provide the user with feedback about the invalid character. What's wrong with these two cron jobs? I have the following cron jobs defined.  55  8   *   *   3   /usr/bin/php /home/mark/dev/processes/customClient/events.php &gt; /home/mark/dev/processes/customClient/events-`date +%Y-%m-%d --date='last Wednesday'`-`date +%Y-%m-%d`.csv 0   9   *   *   3   /usr/bin/echo 'The csv for last week, trying my hand at automatiging this' | /usr/bin/mutt &lt;emailaddress&gt; -s 'Events from `date +%Y-%m-%d --date='last Wednesday'`-`date +%Y-%m-%d`' -a '/home/mark/dev/processes/customClient/events-`date +%Y-%m-%d --date='last Wednesday'`-`date +%Y-%m-%d`.csv'   It seems to work properly if I run it the above command directly from the command line. But when I checked the running of the script this morning I got an e-mail stating (I'm paraphrasing because I accidentally deleted them) that the back ticks weren't closed properly. Require v8 only contrib module with v9 patch I have an input type="image". This acts like the cell notes in Microsoft Excel. If someone enters a number into the text box that this input-image is paired with, I setup an event handler for the input-image. Then when the user clicks the image, they get a little popup to add some notes to the data.  My problem is that when a user enters a zero into the text box, I need to disable the input-image's event handler. I have tried the following, but to no avail.  $('#myimage').click(function { return false; }); I want to use an old drive as a secondary hard drive without reformatting. But this old hard drive contains my old Vista installation which takes up gigs of space.  I tried changing ownership and it works to some extent but I can not delete anything in Windows/System32 folder.  Is there an easy way to change permissions so I can delete everything?    The solution is to use Takeown as Wil suggested and use cacls to take full control of the files. Since cacls doesn't seem to be recursive, I fired up cygwin and ran this command to recursively change all the files:  for d in $(find directory-of-interest -type d);do   cacls $d'/*' /e /G username:F; done   where directory-of-interest is in my case /cygdrive/g/Windows and username is my username.  I had to manually run it on directories that had spaces in its name. But after all this, I can now delete the directory. Warning: it seems to me that cacls can potentially royally screw things up if improperly used. How do you update an Excel file (Data Refresh and update formulas) WITHOUT opening the file? I have an Excel file that want to update and save automatically with out having to open it or manually interact with.  Manually, I open the file up and hit data refresh which goes and does a SQL query and then hit F9 for the formulas to update and then I just close/save.    (I then would mail the file out to people using a perl script or use SAS JMP to run some numbers/charts and also mail them out.  Basically I need to script some things which require the XLS file to be updated.) What's the difference between the server version and the desktop version? How can I use ranges in a switch case statement using JavaScript? Software for measuring internet traffic? I'm interested in finding a free piece of software for Windows XP &amp; 7 that allows us to measure both incoming and outgoing internet traffic, but not traffic between users of the local network.  I live in a shared household with three others, and we're interested to see which of us is using the largest amount of our monthly internet quota. We're all happy to install the necessary software.  Any suggestions? I have some music discs, but every time I put it in a jukebox I can't hear it. It says it's playing, my friend (on PS4) says he can hear it, but I don't. All other audio is fine, I can hear the game audio fine, even if I have a world that's only me: it still doesn't produce jukebox sounds. It visually shows that it's playing (the notes come out of the jukebox) but there is no music. I play on Pocket Edition. Can someone help me resolve this issue? Android reject incoming call Why can lstlisting not be saved in a command? Calculating frames per second in a game Do opposite categories always exist? Virtual Box Won't Accept .ISO To Install OS Much as I loathe Microsquish's Word, it does allow you to insert into a header or footer the automated text "Page X of Y."   When using InDesign, it's easy to set up the "Page X" part on a master page. But is there any placeholder character for the Y? That is, it will count the number of pages in the document, either in an absolute or a relative-to-the-section fashion? Every now and again I narrowly miss sending out something with a footer which reads "Page 4 of 3," and I would love to know if there's some way around that. Possible Duplicate:          Most commands I use in linux behave exactly the same whether I include the trailing slash / character on the end of a directory name or not.  For example:  ls /home/cklein ls /home/cklein/  cp foo bar cp foo/ bar/   When does this trailing slash matter?  What is the semantic meaning of the trailing slash? Can anyone please give an example of why the following definition of $\displaystyle{\lim_{x \to a} f(x) =L}$ is NOT correct?:  $\forall$ $\delta &gt;0$ $\exists$ $\epsilon&gt;0$ such that if $0&lt;|x-a|&lt;\delta$ then $|f(x)-L|&lt;\epsilon$  I've been trying to solve this for a while, and I think it would give me a greater understanding of why the limit definition is what it is, because this alternative definition seems quite logical and similar to the real one, yet it supposedly shouldn't work. Why multiplying fractions is equal to multiply the tops, multiply the bottoms? $$\frac{a}{b}\times \frac{c}{d}=\frac{a\times c}{b \times d},$$ And why $$\frac{a}{b}\times \frac{c}{c}=\frac{a}{b},$$ Also why $$\frac{a}{b}+\frac{c}{b}=\frac{a+c}{b}.$$ I understand it, but I want a mathematical approach as a math student proves it. Also I want to know the mathematics topic of this question (number theory, logic, etc). A full answer is not necessary. Just a reference. How do I convert an argument list to a sequence of arguments?