CaptainPanic

Why not use a really big cannon? In the military, shells and mortars and such are actually becoming "intelligent", meaning that technology exists that will survive a huge acceleration. The only thing you would need is a much larger cannon, and a longer acceleration (but not necessarily a higher acceleration). Possibly it can simply be powered by pressurized gas, not explosives? I haven't done the math yet, but this seems a simple solution to me... although I can imagine that it's not suited for manned space flight

That's probably due to the inflated egos of the politicians *apologizes and points in the right direction to get the discussion back on topic*

If you already know how the graphical method works, you should be able to derive the formulas from such a graph. (Like a straight line with slope "a", not through the origin (0,0) will give something like Y = a*X + b). There is no alternative way - the graphical method and formulas are essentially the same method. Of course it's easier if you don't have to derive a formula - which is why I will give you the following: I'm not 100% sure that we're talking about the same thing but I have a strong feeling that you're dealing with "Michaelis Menten" kinetics here. That's a keyword that should give you some Google hits. sorry for not answering your question - it's our forum policy not to answer homework questions.

I can definitely see the benefit of a subforum for papers. Both for the forum in general, and for its individual members. Whether it will be popular depends on the members here. Personally, I don't like reading scientific papers (the language used in those papers is just a pain - sentences of half a page and words that I don't know)... How do you propose to deal with the following points: 1. Papers are often not free. 2. The claims made in a paper are often not listed clearly, so discussions might not have a clear topic. 3. Avoid people who will just advertise their personal research with no interest in taking part in the discussion itself (scientific spam).

The 67kW is correct. The 22 631K is based on some assumptions, but they are "best case scenarios". I have provided the entire calculation. Please point out where it is wrong if you think it is. 1. The OP wants to heat 2 liters in 8 seconds, not in 1 minute. 2. He also wants to increase the temperature by 50ºC, not 20ºC. 60/8*50/20 = 18.75 Hey, that's a coincidence: 67 kW / 3.5kW = 19.1 It's no coincidence that the values 18.75 and 19.1 are almost the same. You're trying to use a machine that's severely underpowered for the task. About 19 times underpowered to be exact. And the inlet isn't so much the problem. It's the surface area of the hosepipe (the outside) through which we have to transfer the heat. The heater you show probably has a pipe in it in the shape of a coil or something... not just 10 cm straight pipe (and that's it). If you think the calculations are "a little high", then please show why, and don't just say it's wrong. I think the data from you actually confirms that we're completely correct.

The main problem here isn't so much the delivery of 67 kW. Any medium sized boiler can do that... and industrial boilers can easily do many, many times more. The problem is that all this heat has to go through an area of just 31 cm^2... which means that the heat flux is impossibly high. Since we are not about to re-invent physics, I propose we look for an alternative design. But again, since our OP does not give any additional info, we cannot improve the design. Perhaps we should (for once) end a thread with "it can't be done, we're sorry". the problem is a practical one, not theoretical - as I explained before.

Yes.

Although the amount of posts I have on my name don't suggest it, I don't always have time to search around for 2 good posts. And I refuse to just click on some random posts simply because I need to give rep to a certain person. And if it wasn't for this thread I made here, I would have forgotten about giving negative rep altogether by now.

Split up the democrats into 3 parties. Split up the republicans into 3 parties. Vote again. Have the 6 new parties form a coalition government with the already existing parties. Have that new coalition government figure out who is the best person to guide them - and that will be your head of state. Alternatively, you keep the presidential elections as it is, but choose only the rest of the government according to the new way. That way you can have a lot more freedom to vote exactly what you think is the correct party, and a larger chance that this party will take place in the government. Democracy is not about who has the most money to spend on a certain topic. It is about who has the most people supporting a certain idea. No, you had 1 choice. Without a chance for a coalition government, it was completely pointless to vote for Nader. And the choice between republicans and democrats seems pointless too, since the social healthcare topic is being raped and murdered from all sides right now. Oh, comon! The problem isn't so much that the politicians don't take unpopular decisions (they shouldn't do that anyway). The problem is that they actually DO take unpopular decisions all the time. the problem is that the general public first gets brainwashed into thinking it is the right thing to do... With proper information, the wars in Afghanistan and Iraq would have been unpopular. The Patriot act would have been unpopular. A law system that sends about 1% of its population to prison would be unpopular. And a social healthcare system would be popular. Democracy is dead if the majority of the population of the "land of the free" seems to disagree with my points here. Name me one topic where Washington did not choose for either big money or religious ideas. Just ONE topic would be sufficient.

1. I think it's pointless to try to change a definition. It will only create confusion. Then again, that's exactly what trolls do. 2. If there were only trolls and sheep, the concept of the "internet forum" would have died a premature death many years ago. Dr. Lou Natic is a troll. He's right.

Don't ask CaptainPanic - He can't sing - Oh, wait - This is an online musical, so big chance it's without sound. Well, don't ask him anyway!

In addition to some other post I made in another thread: Democracy is dead if the agenda of the politicians is made by lobbyists. What's the point of voting if a group of companies can spend a rather negligible amount of money (380 million is negligible on the scale of an entire country) to remove one of the most important political topics from the political agenda? I urge Americans to take (non-violent) action against the destruction of their democratic system. It's bad enough that you only get 2 options in the elections, but it's unacceptable that companies can then reduce that to only 1 option (effectively making the USA a dictatorship).

Depends on your definition of a "salt" of course but' date=' SnCl[sub']4[/sub] Yep, it depends on the definition. I always learned that a salt is a compound that has an ionic bond (i.e. is composed of ions). If SnCl4 has covalent bonds, then that means it's no salt, even though it is composed of a metal and a halogen. The interesting bit is what happens to SnCl4 when you dissolve it in water. I haven't looked it up, but my gut feeling says it will break up into ions. However, I can imagine that people put this one in the category of salts, which does make the definition of "salt" a bit more vague.

I agree with the system where you cannot give rep to the same person twice... But I recently gave negative rep to someone (for a stupid post which was scientifically wrong, and also off topic), but then I found that the same guy had posted a very decent post somewhere else... but I wasn't allowed to give positive rep (I had to spread it a bit first). It turned out that the person wasn't a stupid spammer/troll, but I just had just found his/her worst post first. I wanted to encourage him/her to stay because of the other post... but now I gave only a negative message. Therefore I propose to change the system a bit so that you can only give positive rep to the same guy once (and then you have to spread it a bit before giving it again)... and the same for negative. But it should be possible to give positive directly after negative, and vice versa. It's not possible to abuse this, IMHO.

Almost a week after the first post and plenty of feedback from us, and the guy hasn't replied yet. I conclude that he's not interested in any discussion, and just wanted to attract some extra visitors to his website. Spam. No surprise actually.

That doesn;t make a lot of sense to me. Mechanical energy most likely is kinetic energy. Something that moves has kinetic energy. And the wind turbines (or possibly sea turbines) are the only devices that convert kinetic energy into electricity. Solar panels convert radiation (which is actually heat - the sun is really hot and therefore it radiates) into electricity. And so do all kinds of biomass energy: plants need sunlight to grow. You might want to rephrase that last bit if you plan to put it on your website. I also wonder if we're discussing anything at all here - I think it's just spam (advertising a website).

Umm... yes... true. Stupid people can be fooled more easily. But it's not the point I tried to make. Well, to be honest, I didn't really try to make my point in my previous post So, what's wrong with the democracy in the USA - why is it no democracy? In democracy, because everybody can (in principle) be a candidate for some job, you get a wide choice of people to choose from. Because people will vote for the person they feel best represents their view of how things should be run, you get a representation of the population as a result. -When those people that you can vote for start deliberately misinforming the voters, the system also automatically crashes. People will vote for the wrong candidates. -When voters choose their representatives only because of 1 important topic, then the system automatically crashes. All other points that are less important are completely neglected when people vote. That means that somebody might be a convinced socialist, but votes McCain because the person is dead against abortion or something. You need 10 parties, or more, to be able to give everybody a chance to vote for something that makes sense. That is the main problem with 2-party democracy. The democracy in the USA already has suffered from the 2nd point for a long time. The 1st one will bring it to its knees, and I am afraid that some nutcases in the USA are gonna blame Obama for it - while he seems to be the only one who actually gives some facts every now and then that are accepted by well-informed people across the Atlantic...

So, first of all, this is our forum, so we'll discuss this project here - not on your website. I'll comment on the parameters of the project: Some comments: 1. So, in short, you want an autonomous city state, which gives a good example to the rest of the world. You will not be autonomous. You will not be independent. You will be just as integrated in this small world as everybody else. Because it's 2009, and we have internet, phones, etc... and if you like to eat some imported foods, have an ipod or affordable computer, you need to enter the world market. 2. You want a system designed by knowledge and logic. That's a "petty political ideology"... just like socialism and capitalism and all the rest are political ideas. Most of them will include knowledge somewhere. It's all equally petty, because people will just bicker over it until they get it the way they want. What you have in mind is system where everybody wants the same. That's called a utopia. People want influence. And you suggested before that you prefer not to have people around who disagree with your ideals. What if they were BORN in your city state? Suppress them? Suddenly that sounds more like the ideas of some other regimes that we think are evil. 3. And it gets worse. You also aim to convert the rest of the world. So, not only do you not tolerate people who think differently in your own society, you also wish to change the rest of the world into your technocratic world. What if people refuse to be converted? I can guarantee you that people won't listen - because they never have. 4. In short, I think you're developing a scary project here. If you like a knowledge based economy, based on science with highly educated people: Go to Scandinavia or any other country in Europe. We're pretty damn close to your ideals, but we prefer to give people the freedom of thought as well. Sorry for being 100% negative about something that was born out of pure goodwill. You mean to do the right thing, but it'll end in tears.

wikipedia? contains lots of data... though perhaps not in the format you want. You can actually download wikipedia.

You know you don't live in a functioning democracy if your politicians deliberately misinform the public to gain political power. I have no more to say. For me, the USA is not a democracy any more... sadly, its system collapsed. I don't understand how the politicians get away with it. Destroying democracy, telling lies, and occupying themselves only with gaining power. Aren't they supposed to represent the population or something?

You must know one of the main laws of electricity: [math]V=I*R[/math] What's the formula for resistance in a wire? What's the formula for power (as a function of V,I and R (pick two out of 3))? Those were highschool formulas for me - so I expect that you know them too... and since this seems homework to me, I won't tell you If I know the resistance of the wire, I am able to derive a formula for the power it will deliver (in the form of heat)... and with that you can calculate how long it will take to heat your liquid. Please realize that if you suspend a coil (wire) in water, you might severely decrease its resistance (since you effectively shortcircuit it by the water, which is conductive). After that it's just a matter of insulating the liquid so that all the heat stays in it. With a perfect insulation, you will reach the desired temperature regardless of the power.

It's produced in huge quantities by lifeforms on this planet, but the purification is really hard. It's cheaper to use the process as was linked to by insane_alien.

Don't you guys differentiate between a misdemeanor and a felony or something? Do both fall under the category of "crime"? In the Netherlands, you have to be doing something worse than jaywalking in traffic for it to be called a crime (or more correctly our translation for "crime"). For example, going 100km/h in a pedestrian zone in a truck would be a crime. Jaywalking not. Crimes are also handled by judges, while traffic cops can give you a ticket without any judge being involved. I'm not 100% up to date with the laws and definitions in the USA... but I thought this question to make sense in response to the remark of Sisyphus. But we might go slightly off topic

Assuming the maximum value of the moon's surface of 107C, a water molecule will have a mean speed of: [math]\overline{v}=\sqrt{\frac{8\cdot{R\cdot{T}}}{\pi\cdot{M}}}=\sqrt{\frac{8\cdot{8.3145\cdot{(107+273.15)}}}{3.14159\cdot{0.018}}}= 668 m/s [/math] (formula from Atkins Physical Chemistry - a textbook made of paper) ... which is only 28% of the escape velocity, and slower than the orbital speed of the moon. I just thought it would be funny to add these numbers. I am not claiming that the numbers will have any connection to the presence of water, or to the fact that it seems so rare (in other words, I add a disclaimer here that I'm no expert)... but I wouldn't be surprised if there is a connection. As mentioned, the value is the mean velocity. So, there are plenty of molecules which can have a higher velocity... values higher than the escape velocity are probably well within the realm of possibilities... Sadly, I do not know the standard deviation, or the type of chance distribution of the mean velocity of molecules...

So, the moon that orbits a planet that has lots of water has some water too? Amazing. But it's good that somebody finally found out where it was hiding.