studiot

No problem. I don't recommend using the abbreviation p(4) for position 4 since p(something) is normally used for probability(something). Think of your tree (No I don't wnat to draw one either) Position (1) has 5 branches Let us say postion (1) is an 'a' This must immediately strike other branches that contain an 'a'. So you have a smaller tree than if 'a' was still available. It is exactly the same for whatever vowel goes into position (4) - it must make this vowel unavailable to other branches by striking them out. It's just that we don't know which one, but it doesn't matter since all the branches have the same pattern, there must just be one fewer for every other letter position. So we have (26 - 2) = 24 in the second position. In the third position we have already struck out the branches that are used by position (4) so we don't need to do it again. So we simply take one off the available total (it could still be a vowel) 24 - 1 = 23 position (4) the second vowel now comes after 3 preceeding characters have been chosen and these three could all be vowels, leaving 5 - 3 = 2 available vowels. I asume you are OK with the 9 and the 8 for positions (5) and (6) ?

Did you mean the 2 at position (4) or the reduction of 2 for position (2)?

OK So Position(1) is a vowel and can therefore be chosen in 5 ways. Position (2) can be a vowel but cannot be the vowel in position (1) or the vowel in position (4) (although we don't yet know the second vowel) That means there are 2 (not 1) unavailable letters for position (2). That means there are 26 - 2 = 24 available letters. Can you now complete?

No I have already said the memo is not wrong. Fiveworlds has already said he is just guessing. Have you tried following my method?

Casualkilla do you wish to continue, despite the incorrect interruptions?

Note your memo answer is the product of 6 factors, and you want a 6 character password. Is this a coincidence? The first character is a vowel. There are 5 vowels. So how many ways can this be chosen? So work through the first, second third etc asking each time the same question.

Yes that is quite true, but that is also not the system employed here. For prestressing the stressing force to the stressing wires is applied before the concrete is poured. This is done between external fixed anchors, which must be strong enough to support the prestressing force. The concrete is then cast and as the cement reactions proceed the paste shrinks around the wires and binds firmly to them along their entire length. Once the concrete has hardened in this condition the support anchors are removed and the wires attempt to shrink back to their original length. However they are firmly grabbed by the concrete and remain stretched. So the prestressing force is balanced by a compressive force, developed in the concrete. No external agent is then required and the lintel may by lifted and built into place. Motorway beams and building floor beams are manufactured on this principle. The alternative is the cast the concrete first and let it harden. Then the post tensioning is applied via a cable (or rod) external to the system. Usually no external anchors are required the reaction is obtained directly from the concrete being stressed. As to the inner working of the patent official's mind, I can't answer that one. I remember Joe Lucas trying to steal a march on other battery manufacturers, back when most auto batteries were housed in heavy rubberised glass containers. They managed to obtain a patent for "Battery cases les than 2mm thick" for their plastic case. And they tried to charge other manufacturers on the basis of this.

Yes that's a good way to put it. The difference between prestressed and post tensioned concrete is that the anchors become redundant in prestressed concrete.

It is, but it is a very useful fictious force as it transforms a problem from one of dynamics to one of static equilibrium. It is known as D'Alambert's Principle. This link is simpler than Wiki for a first reading http://www.britannica.com/EBchecked/topic/150132/dAlemberts-principle

Actually, John there is more to this idea than post-tensioned concrete (It is post tensioned, not prestressed). The post tensioning is carried out against a ground anchor and the whole system depends upon the stability of the ground anchor in the seismic disturbance. This is not, however, new.

I'm sure I know substantially less than ajb about this but I do like the term 'kittygory' for 'small category'.

I don't follow what this has to to with either order or entropy.

Potassium Chlorate is poisonous (used a weedkiller); it is also dangerous for other reasons. If you do not already know the answer to this you should not be 'experimenting' with this substance.

I wasn't convinced by this link since they only mention 'cathode' once, as 'cathode materials', and do not indicate a polarity. Farady introduced the terms anode and cathode in the 1830s, along with his two laws of electrochemistry. Here is the modern version that has been in continuous use since that time by the whole electrochemical industry, not just the battery section. Taken from Moody's Comparative Inorganic Chemistry. I have highlighted the definitions.

If you look carefully at the picture in the first link in my post#3 you will see that this definition also conforms to the (electro)chemical definition, ie they are the same. Electrons are shown leaving the zinc anode. Further down there is a picture of an (i'm sure familiar) accumulator. Unfortunately it is probably (no disrespect meant) beyond auto techs to understand that the accumulator acts as two different devices when it is charging and when it is supplying current and that the terminals are simply the lumps of metal, but the names anode and cathode are defined by their function, not by a particular lump of metal. So that the terminal names should therefore be reversed when charging and discharging. So auto techs call one of the lumps of metal (terminals) the anode and (wrongly) stick to it. For a battery being discharged, the terminal marked + is the cathode, while for the same battery being recharged, the terminal marked + is the anode. The Zener diode is an unusual case since it is normally operated in reverse mode. However it does work as a normal diode in forward mode where the definition works. So a simple approach is to say that since we are talking about reverse current the reverse definition applies. Alternatively a good discussion is to be has here http://www.av8n.com/physics/anode-cathode.htm

Sorry to have caused the confusion, I have editied my previous post to what I should have written. Rectilinear = in a straight line Curvilinear = in a curving line The linear part = line and the prefix tells whether the line is straight or not. As to the abrupt part I suppose a rolling irregular object could have corners that follow a cuspate path and thus suffer abrupt changes of direction.

Yes I would agree with that definition. The point is that having formed the conjecture you should seek firm evidence as ajb reported he did. Another application of the scientific method is in detective style work. Here you have a definite outcome effect or event and you are seeking an explanation. I have conducted quite a few failure investigations where you work through questions like Was it fatigue? Was it overload? Was it chemical? Was it an outside agent? and many more. In conducting such an investigation you start with not one but several speculations and systematically eliminate them. So speculations, per se, are not bad. It is what you do with them that counts.

The uncertainty principle ensure that changes of magnitude take a finite time to occur for massive particles (particles with mass) Special Relativity ensures that particles without mass (photons) cannot change velocity magnitude. But sure both acceleration and magnitude are vectors so can instantaneously change direction when going in curvilinear motion.

Do you mean position or distance?

I agree that the Wikipedia definition is cumbersome and not user friendly. The anode is the terminal of a device where electrons leave or conventional current enters. Is IMHO much easier to cope with. This is actually equivalent to the Wiki definition, despite the vebiage.

Unfortunately all too many of them do not understand statistics properly and end up producing garbage theories. I particularly like the story of Abraham Wald and the Ministry of Defence. http://www.ionica.nl/wp-content/uploads/2013/10/Wald-Vliegtuigen-Bayes.pdf

I believe the word was reduce not stop.

Welcome +1

This is clearly not the phrasing of the original question. Nor is your rephrasing a valid description of your attempts so far. @JonathanApps, K1 & K2 are the spring constants for the two springs involved.

Well I would say your last post was not preaching, since it contains attempts to explain your statements, based on views which I assume are honestly held. So I see no reason for negative points. However the good news is that opening the discussion as you have now done has provided the opportunity for you to reappraise your applications of the laws of mechanics. Firstly the powered aircraft. Yes Newton's laws apply, but you have forgotten an external force. There is a force developed by the propellor or the reaction from a jet, which counters the drag, ans supplies the acceleration force when accelerating. Both of these arise from the body of air. (A rocket in space is also subject to the reaction from the exhaust when the rocket motor is operational) As to the balloon you have just put the opposite argument since you (appear to) claim that bouyancy forces do not exist, (or have forgotten them). Therefore by Newton's law, just as you enunciated it, the inflated balloon, sitting on the ground, will not move. Of course we all know that this is not so. You error lies in considering 'potential energy' in this case, but failing to distinguish between gravitation PE, which does not change during the inflation process, and a new potential that arises within the air fluid, due to the inflation process and exactly equls the work done (as you correctly observe) in inflating the balloon.