imatfaal

Wouldn't slingshoting your spaceship around a planet allow you a high rate of acceleration without the 'g-force' beating up your body?

Nope fraid not. The 'g's that you feel ARE the acceleration. If anything lessens that force (rather than using techniques to help the body cope with it) then you will simply accelerate less.

Just guessing, but in a slingshot manoeuvre surely you would have lateral g to contend with as well

I am quite definitely not on the wrong side of the pond (but then who would believe they were), I also know about double negatives, and most importantly I understand the lyrics of Satisfaction - it wasn't an arch double negative, it was widely perceived as a protest against the tide of commercialism and pressure that young consumers felt. Likewise Roger Water's lyrics - it's a protest song, not a clever use of a linguistic twist.

But there is objective proof - the ability of people (on this forum with whom you correspond) to make predictions based on non-classical physics that would have been impossible without their learned knowledge and the progress in the last 50 years or so based upon the work of people like Feynman and Heisenberg. There are people on this forum whose livelihoods depend on the results of experiment being as predicted and derived techniques behaving as expected - they will provide more physically accurate answers than those who base their reasoning upon intuitive feeling or even upon the mainstream physics of the mid-20C. This could be experimentally proven. If there is a deliberate obfuscation it has failed miserably - we are able to predict with greater precision and depth than we were before the "false-education" through bewilderment that you allege took place.

thanks for the LAtEx

 

this is almost impossible

 

What is? Ask simple questions and you will get answers.

Imatfaal, I'm still not seeing a difference.

 

One in five (ie, ~20% of) American moms — have kids who have different birth fathers

 

[28% of] moms with two or more kids — have kids with at least two different men

 

The situations are identical (that is, plural kids and plural fathers), and only the percentage is different.

The group that meet the criteria are identical - agree. The populations from which this criteria-matching group are taken are not identical.

Thus the larger population will give a small percentage.

Lily - you might find it better to ask specific and simply worded questions rather than post large amounts of stuff that everyone knows to a greater or lesser extent. You will find people on the forum more than happy to help.

There's no way of proving implicit meanings. That's one of the reason people use them to communicate; i.e. it shift responsibility for the meaning to the receiver. That's why you hear loads of public hearings and statements where people claim never to have said something that someone accused them of saying. People know how to be careful with words yet still convey the meanings they want to.

I agree - but when you posit an alternative reading/understanding with no indication of what the alternative intended meaning was or evidence to back up this claim then substantively you have said nothing. The questioning of motives only provides further information when it is accompanied by a logical argument (could be very short and implicit - "cui bono?") otherwise it is merely the automatic undermining of all comment through innuendo

Generally that's true but in light of the context you posted for the Feynman quote, I can see how it refers to avoiding misinterpretation. Maybe I misinterpret it just because I can't stand the defeatism of giving up linguistic description and reasoning altogether to avoid the risk of misinterpretation. That would be as bad, imo, as giving up progress in science and technology altogether because some people use them to make deadly weapons and destructive and oppressive technologies of control. Oh wait, did I just tie it back into the nuclear weaponry issue?

Watch the lecture - apologies for the larger than necessary mugshot of billy g http://research.microsoft.com/apps/tools/tuva/

first of all .. thanks for the reply .. nobody does that .. these days

 

actually i am preparing for a maths exam that deal with numerical analysis .. also called numerical methods

 

these are the stuffs in it

 

Damn - I hope you have some revision time!

Bisection Method

uses idea that if f(a)>0 f(b)<0 then the root must lie in between

Find mid-point of your interval f(m) - it will then be clear that the root lies either between f(a) and f(m) OR between f(b) and f(m) as only one pair will straddle 0

start again with f(a) or f(b) and f(m) and find new midpoint

rinse and repeat

Will run into trouble if more than one root between the two initial guesspoints - this is the case if the curve touches the axis. Converges on a range not a value. Slow. Need continuous function

How do you know that Feynman wasn't playing with words to convey covert meanings? Regardless, the point is what value there is in quantum physics being incomprehensible and why Feynman would regard himself as "safely" being able to say so.

We don't know he wasn't playing with words - but, in general, the simplest explanation is the best, until and unless it is shown to be deficient. There is no quest for 'value' - the quest is for models and theory that prediction and explain. A fuller version of the Feynman quote is as follows

There was a time when the newspapers said that only twelve men understood the theory of relativity. I do not believe there ever was such a time. There might have been a time when only one man did, because he was the only guy who caught on, before he wrote his paper. But after people read the paper a lot of people understood the theory of relativity in some way or other, certainly more than twelve. On the other hand, I think I can safely say that nobody understands quantum mechanics.

Again, the simplest explanation for the use of the word safely is that Feynman was contradicting one idea and replacing it with his own and he was sure that his new idea was unlikely to proven wrong ie "I can safely say this without fear of contradiction". If you are to impute non-standard usage and covert meanings then the burden of proof is on you - everything can be questioned and subtextualised (I am pretty sure I just made that word up) but some form of argument is needed to give foundation to that questioning.

The quote is taken from the Messenger Lecture series - it's all on-line, I will dig out a link

The next line from the lecture expands on the theme of this thread

So do not take the lecture too seriously, feeling that you really have to understand in terms of some model what I am going to describe, but just relax and enjoy it. I am going to tell you what nature behaves like. If you will simply admit that maybe she does behave like this, you will find her a delightful, entrancing thing. Do not keep saying to yourself, if you can possible avoid it, "But how can it be like that?" because you will get 'down the drain', into a blind alley from which nobody has escaped. Nobody knows how it can be like that.

sciencer in the original post writes ..........

If 0=2-(1+x), isn't the correct answer x=2? A simple question, before the author of the book is notified of the print error

 

 

 

The simple question is .......... If 0 = 2 - (1 + x ) , isn't the correct answer x = 2 ?

 

The simple answer is yes . The correct answer isn't x = 2 . The correct answer also isn't 2435782 . 815243 !

 

When computer programming interpreters ask these types of questions , ( on those circuit boards under your keypad for instance ) be sure to know what they are or aren't asking and what you are or aren't asking them to ask !

"isn't the correct answer...?" is generally considered to expect an affirmation if the postulated answer is the correct answer. This question is not the same as the re-ordering of words to make the statement "the correct answer isn't"

The question "is the correct answer...? is asking a simple question. "isn't the correct answer...?" makes a proposition and rhetorically asks for its confirmation

btw, Marat, do any of your posts not involve some form of killing?

*****

I hadn't noticed my apparent death obsession! I hope it is just because situations involving death create more pointed ethical dilemmas.

we could call this obsession the "death of marat"

Sorry. I'll get my coat and leave.

trying to answer airbrush's question;it is that visible universe is usually thought of as that portion of the universe which could be observed using EMR-detection - and we can detect/observe nothing during or before the universal opacity of the era of last scattering which finished around 380-400k years after BB. There is clearly a part of the universe that is within our past light cone earlier than 380000 years post big bang - otherwise where did we come from - and that part of the universe will never be visible using EMR-detection. The observable universe is time-limited because of the era of last scattering - the past light cone is not. When/if we can use neutrinos or gravitational waves to probe the very ancient universe (ie detection methods that are not blocked by the opaqueness of the universe then) the observable universe will increase in magnitude

I think its just badly phrased. A child cannot have more than one genetic father in the normal run of events - the figures given can be broken down as follows

20 percent of women who are a mother in US have more than one child AND have children with different genetic fathers.

28 percent of mothers with more than one child have children with different genetic fathers.

In the first phrase the population group is large (women who are a mother) - and has two conditions (more than one child) AND (more than one father)

In the second phrase the population group is smaller (women who have two+ children) - but it only has one condition (more than one father)

As the size of the group that meets the condition(s) is the same for both phrases - and the population size is smaller in the second then the second percentage must be bigger.

I hope I havent made the confusion worse

I am in danger of sounding like a big business apologist, but:

If an industry must take into account (either through insurance or increased costs) the potential and subjectively, individually-judged social consequences of any known hazard then nothing will ever pass a cost-benefit analysis. Industry does need to be able to limit liability and to avoid the need to include the social cost of taking certain risks within its calculations. I think it needs to be accepted that a corporation can take into account potential lawsuit for future unforeseen negligent acts, but that no corporation should see litigation costs as an alternative to solving a current problem.

And perhaps the system desired by Price Anderson is exactly that less objective/more subjective system that you call for. As the damage would be community wide, and would threaten entire social make-up, then the risks can only be covered by community/government based schemes. Normal tortious litigation would not have either the facility or scope to compensate a community that suffered in this manner.

I don't claim to be an expert on Price-Anderson - but laws insisting upon minimum insurance levels, mutual contingency funds, a multiple tiered payout plan, no blame litigation etc in return for limitations of liability, and an ultimate governmental funding tier is not restricted to the nuclear industry. the oil and shipping industry have similar set ups.

To an extent you are correct, but more importantly they demonstrate that a huge potential hazard exists - and that to facilitate the forward movement of that industry, a risk will be taken jointly by all participants of the industry and the government. The hazard is enormous - but the risk is acceptable.

Surely if we cannot pin the electron down to some understandable form , we are in a ( blindfolded ) position of not understanding exactly what makes the whole of chemistry, much of physics, much of the workings of the universe, work.

.

Fun and kinda scary ain't it?

Swanzontee has mentioned comparative risk analysis looking at a dollar spent in one area with perceived hazard or another area where danger is actual - there is also the more accountancy based cost per unit of production analysis. Every penny spent on a piece of infrastructure has to be added to the cost of the product. Who initally pays this extra marginal cost is a matter of policy (it could be subsidy, it could be reduced commercial profit, or higher retail bills); but in reality when all accounting is done it is the taxpayer/end-user who pays. The capital costs of building a nuclear power station have to be defrayed eventually one way or another - and in evaluating the project these costs are placed on the price per giga/terawatthour. At a certain price per unit energy we decide that the capital project is not worth continuing with.

The same accountancy applies to the production of gasoline at filling stations from crude oil; we could make the transportation, production, distribution etc safer for the workers involved and lower risks of environmental damage - but this will put up the price at the pump. In the end we make the decision that we can put up with hundreds/thousands of deaths per year and major spills every few years as long as the price of gallon stays down; it's a nasty calculus, and one we don't tend to make consciously or overtly.

Agree with Ophiolite - it's a confusion. If you google circularity system but not circulatory you only get a handful (well 1400) answers and first page results all seem to be confusing the two terms. OTOH circulatory system is a very important concept, especially the double circulatory system

Apparently I have become an admin as well! I think I might close some threads for the hell of it - I just have a feeling it might not work that way. I also have a pretty good idea what is going on and it is nothing to worry about

Can I get to meet Tom Cruise?

I think the opponents of cloning and other "human-technologies" rely on the discredited and illogical slippery slope argument. It is arbitrary line-drawing with post-hoc rationalisation and moral justification

Cap'n - once the conspiracy theories come out to play the obvious objections are quashed. The only time that Libyan oil ceased to flow was during the last revolution and now - and as you point out that does not tally with this being solely about the oil.

If Mercury were made of iron, I would find it hard to believe that 400C on one side would be insulated from the -100C on the other side. What prevents that heat from conducting through the interior? It's not like the energy can radiate away on the sunny side.

Well the dark side clearly does get heated by the light side as the darkside has a temperature of 100K - which is considerably higher than the space that surrounds it. It is clearly wrong to suggest that the sunnyside would be the same temperature as the darkside - and it seems that the equilibrium is that the side with no sunlight gets to around 100k before its emission balance out the conducted heat from the sunnyside

Great site CaptainP - from a look at some of the photos - winners had over half a tonne supported by less than a kilo of spaghetti

Not silly at all . I think it carries on throughout an engineering education - I have certainly seen undergraduate level engineers being asked to do this same task. This was in a competition that was set to schoolchildren from 8-18 yrs and students at two local universities (using spaghetti, super glue, and mars bars) a group of 16 years olds beat all competition!

There are real architects on this site and hopefully at least one will respond - but I guess the first thing I would want to think about is the strengths of my materials: under tension, compression, shear, twist etc. Secondly what is the weakness of my joints? What sort of anchor on the sides is allowed?