How was the rule of a handlebar of a door decided?
485914
The handle bar on a door is called a "panic bar" and is designed to be "pushed on" by people choking and blinded by smoke in a burning building.  If the crowd panics they will head for the door but may not be able to operate other mechanisms.  Panic bars must also be installed on both side of a revolving door that would become jamed with people during a fire.
345010
I don't know when, but I do know why.  The half seat is on the side the door opens.  It allows room for students to get out the back door easier without a seat in the way.
189815
I don't want to re-invent the wheel, so please visit these links.\n\nClear history on yahoo search website: http://help.yahoo.com/help/us/ysearch/basics/basics-25.html\n\nClear history on Yahoo Toolbar: http://help.yahoo.com/help/us/toolbar/toolbar-10.html
965400
All 3 types of levers. for one.\n\n\nNext...
547283
This tradition dates back to the times when children lived at home unil they married, and were very much under the control of their parents. The voting age was twenty-one, when 'adult status' was officially conferred, and as Whickerman advises, a front door key was issued for independent access to the family home.  As an adult, you were considered free to come and go as you pleased rather than according to your parents' wishes. Thus, you were now entitled to "the key of the door".  (It's a British tradition.)
76630
The mechanism is called (oddly enough) a door closer.
173581
Probably middle english. Before the advent of the center fixed swinging rudder ( 14th C. ) rudders were attached externally to the rear , aft ( short for after ?), section of the vessel. \nThe Steerboard would preferably be on the side of the vessel not tied to a quay or pier.  The other side might be " port" if it is the adjacent side to where the vessel ties up. \nThat is just my guess. \nBow, I don't know.
497266
The story -- often repeated in print & orally -- is this:\n>\n>    The phrase "Rule of Thumb" comes from English Common\n>    Law which deemed it a man's right to beat his wife\n>    with a stick no thicker than the diameter of his thumb.\n>\n>For the last 6 or 7 years I have been looking for **RELIABLE** confirmation\n>of this, and/or the earliest legal reference to this "Common Law."  I have\n>found MANY sources that *claim* that it stems from English Common Law, but\n>searches of legal decisions (by friends who are lawyers or legal researchers)\n>and/or of Blackstone, etc. never turn up any actual reference to a legal\n>decision citing this "common law" or even any reference to it.  I'm beginning\n>to wonder if this is another Academic Myth.\n>\n>Please reply privately, and I will summarize for the list if there is interest.\n>------------------------\n>Ruth Ginzberg <rginzberg  AT  eagle.wesleyan.edu>\n>Philosophy Department;Wesleyan University;USA\n \nThe only place I know to look for answers to such questions is the OED.\nIt won't state straight out that such-and-such is the case, but if you know\nhow to read the OED you can often figure out likelihoods.\n \nThe whip thing is a bit of modern folklore.  It is typical of such back-formed\nexplanations well-known to linguists and folklorists.  (The folk etymology\nof 'asparagus' as 'sparrow-grass' and the plague interpretation of 'Ring\nAround the Rosie' are two others.)\n \nThe real explanation of 'rule-of-thumb' is that is derives from wood\nworkers (or other constructors) who knew their trade so well they rarely\nor never fell back on the use of such things as rulers.  Instead they'd\nmeasure things by, for example, the length of their thumb;  they measured,\nnot by a rule(r) of wood, but by rule of thumb.  The term was already in\nmetaphorical use by the late 17th century.\n \nI'd like to see the accumulated references to the wife-beating explanation.\n I wonder for instance just when that back-formed 'origin' came into being?
753403
http://en.wikipedia.org/wiki/PCB_layout_guidelines
134473
The answer is obviously (A). The bar may shrink a little, but it can't disappear completely, as the options B, C and D imply!!\nHence, by process of elimination, the answer is (A). :-)
625647
"Pommel" originally comes from the word for an apple and was first used for a round ornament etc, it then came to apply to the knob at the end of a sword or dagger handle and from about 1450 was also applied to the projecting front part of a saddle and, because the 'handles' on the type of horse you specify resemble those that is why the name arose.
750944
In mathematics and physics, the right-hand rule is a convention for determining relative directions of certain vectors.\n\nhttp://en.wikipedia.org/wiki/Maze\n\ns
211038
This depends on the side you are entering from. If hinges are on the right, the handle will be on the left to take advantage of the torque multiplier effect.  If the handle is on the left, it could be a swing in, or swing out door.  What really matters is that the hinges are typically on the inside facing portion of a door and thus will swing in a way that the hinges allow.  Most doors will open into the area in which the hinges are.  Now, if you are opening a door with hinges on the right, you are most likely pulling it open with your right hand if you are exiting because the handle is on the left and that is the natural flow of your body and the door arc, if you are entering, you would use your left hand to be able to push the door in further.  So you see, basically it is all relative.
427903
for race rules applicable in races world-wide, visit the UCI website\n\nwww.uci.ch
1113903
At first the "lefty" had two sides and looked like the down-hill forks in construction. The steerer tube was in the middle and each leg extended past that on the left and right. It was of course heavier compared to the traditional styled forks (fork legs are more or less even with the steere tube). The guys in charge of the Cannondale fork were told to lighten it up so they cut off one side. This style was also used on some motorcycles I believe. Anyway, the advantage of the "lefty" is that you can get more travel out of it that the tradition forks at roughly the same weight. Also, the internals are interchangeable so you can upgrade the low end model to use the same internals as the high end model. The down side is that to remove the front wheel, you have to remove the disc brake caliper. You also need an adpater to true up the front wheel. There is also an adapter needed to transport the bike on roof racks where the front wheel is removed.
1022271
top of frame to crank, ie the pole that the seat run into
973902
Generally there are several areas that engineers usually have to decide, but this depends on what the engineer is trying to do.\n\nFor instance if something is safety critical (i.e. a crane or bridge or tower), then they will choose to make something much stronger than it needs to be.\n\nSay a crane expected to see a max load of 10,000lbs.  The design might actually be able to support a load of 15,000, but you tell the public that 10,000 is the safe limit.  This is called factor of safety and engineers almost always want to be conservative.\n\nNow an engineer could design it to support 100,000 lbs, but this would make the crane much more expensive than it needs to be.  So what happens is they compromise with 15,000 pounds because it is safe enough and not as expensive.\n\n\nAnother topic would be tolerances.  For instance, you want a rod 1 foot long.  I the real world, it's impossible to get something exactly 1 foot long.  We can get close, 1.001 is easy to do, but why do you need such precision if something that is 1.2 feet long will do.  \n\nSo in many cases you see tolerancing on dimensions, 1 +/- .003. That means something from 0.997 to 1.003 is acceptable.  If you want something much closer, say 1.0001, then it'll be much more expensive because it's more difficult to make.\n\n\nHope this helps.