Speed of Light and Relative Velocity
If I run along the aisle of a bus traveling at (almost) the speed of light, can I travel faster than the speed of light?
Could a website force the browser to go into fullscreen mode? I want to run a psychological study for which participants have to look at large images.  The experiment is done on the web and therefore in a browser window. Is it possible to tell the browser to go into fullscreen, for example on button press?  I know there is the possibility to open a fixed-size popup window. Do you think this would be a feasable alternative? And if, what would be the best way to do it? Are there elegant ways of detecting a popup-blocker, to fallback and run the study in the original browser window.  The main concern is that the participants of this study are not familiar with technical details and should not be bothered by them. I am looking for various ways of explaining to my students (in an elementary statistics course) what is a two tailed test, and how its P value is calculated.  How do you explain to your students the two- vs one- tailed test? How can I remap keyboard keys in windows 8.1? I'm looking for a simple utility which will modify registry and would not require running at startup. I tried sharpkeys but, it does not seem to work in windows 8.1. Any other suggestions? Or a simple how-to tutorial for windows 8.1?  Edit: Keytweak isn't working either. Actually I want to map an unused key to function key (fn) and neither sharpkeys nor keytweak detect the keystroke for that key.   Thanks Difference in System. exit(0) , System.exit(-1), System.exit(1 ) in Java After swapping the positions of the hour and the minute hand, when will a clock still give a valid time? I'm used to doing all my coding in one C file. However, I'm working on a project large enough that it becomes impractical to do so. I've been #including them together but I've run into cases where I'm #including some files multiple times, etc. I've heard of .h files, but I'm not sure what their function is (or why having 2 files is better than 1).  What strategies should I use for organizing my code? Is it possible to separate "public" functions from "private" ones for a particular file?   question precipitated my inquiry. The tea.h file makes no reference to the tea.c file. Does the compiler "know" that every .h file has a corresponding .c file? Can you help me with my software licensing issue? This is a  about Licensing.    Questions on licensing are off-topic on Server Fault.  If your question has been closed as a duplicate of this question, then this is because we want to help you understand why licence questions are off topic rather than just telling you "it just is". In all likelihood, this question will not address your question directly, it was not meant to.    I have a question regarding software licensing. Can the Server Fault community please help with the following:   How many licenses do I need? Is this licensing configuration valid? What CALs do I need to be properly licensed? Can I run this product in a virtual environment? Can I downgrade this product to an earlier version? Am I entitled to feature X with license Y? How can I get my graphics card to be recognized in System Info? What is the use of a persistence layer in any application? Force URL link to open with a specific browser I've created a URL link in my dock, however, the link only opens with the default browser. I have safari, Firefox, and chrome (latest being the default) installed in my machine. I'm wondering if someone knows how to default the link to open with Firefox instead of Chrome but still keeping chrome as the default browser.  Note: I'm running Mavericks in my MacBook Pro. Characterization convex function. How do I install gfortran? I am trying to install gfortran in my computer with Ubuntu 12.04 by using these commands,  sudo -i apt-get update apt-get install gfortran   but I found the program saying "unable to locate package gfortran". Then on a Ubuntu page I found some question regarding the same problem and I went through the solution from them but again I couldn't install the gfortran package.  Can anybody tell me how to install it? $X/{\sim}$ is Hausdorff if and only if $\sim$ is closed in $X \times X$ I found  presentation document by D. J. Bernstein. Is it possible to create it in latex?  Screenshot I'm planning to fly from Ulaanbaatar to Melbourne via Seoul (and Kuala Lumpur).  However, can I actually enter South Korea using this visa waiver? I'm hoping to meet a friend there for a few hours before flying. Also, would traveling via Malaysia affect this policy?  Transit tourists bound for another country Eligible countries  Applicable to all countries (save for Macedonia, Cuba, Syria, Sudan and Iran) that are not granted visa-free entry into Korea.  Applicable to…  Those with a visa (excluding Japanses Group Visa, excluding e-visa) or a re-entry permit for U.S., Japan, Canada, Australia, or New Zealand (5 countries) and traveling to any one of those countries through Korea.  Those traveling from any one of the five countries mentioned above, whose final destination is not Korea.  However, please note that the first bullet points are not applicable to those travelling to/from Guam and Saipan, which are unincorporated territories of the United States.   Requirements  Must have a confirmed onward flight ticket for departure within 30 days after entering Korea, in addition to having no record of criminal offence in the five countries mentioned above. Install windows 7 through virtual box I suspect that the name server provided by my ADSL modem/router is buggy. Whenever I browse to a website for the first time in ubuntu, resolving the domain name takes at least 15 seconds.  To work around that problem, I changed the nameserver configuration in /etc/resolv.conf from 192.168.1.1 (my ADSL modem) to 8.8.8.8 (google's primary DNS). This seems to fix the problem, but unfortunately my changes to /etc/resolv.conf are overwritten by "NetworkManager" at each startup.  What is the proper way to configure the name server IP in ubuntu 10.4? Here are two sentences:        Once he got the passport, he went to the Chinese consulate in Toronto and applied for a visa.   Once he got the passport, he went to the Chinese consulate in Toronto to apply for a visa.      Are the two sentences grammatical, and do they sound natural?  If they are both fine, what's the difference? Find the limit: $\displaystyle\lim_{x\to \infty} (\sqrt{x^2+x}-\sqrt{x^2-x})$. Why is "our today's meeting" wrong? One of the answers to  question states that &quot;We shall discuss it in our today's meeting&quot;  is grammatically correct. To me, that sentence is clearly wrong. While in today's meeting is fine and in our today meeting is OKish (though at the very least clumsy), there's something about the possessive there (our today's) that makes it wrong for me. I would read that sentence as in our today's (as opposed to your today's) meeting. Similar to in our car's trunk where the our clearly modifies car and not trunk or car trunk, the our in our today's seems to be modifying today's and not meeting. So, my questions are i) is it actually grammatically wrong to say in our today's or is it just a question of usage? and ii) if it is indeed wrong, how can we explain its wrongness?