What is the proper way to apologize for smearing rape victims?
By apologizing. Sorry, but that's all he can do.
But that's not my point. Last I heard of the case, the girls never pressed charges against him. They merely wanted to have him tested for VD. The prosecutor pressed charges (as they must do under Swedish law) when she (because I think it was a she?) heard their story.
The prosecutor thinks there is a rape case here. Whether a rape has actually taken place is now up to the courts (since the girls themselves have not wanted to press charges for rape we can't really say there was a rape at all until that has been established in court).
This system is in place to prevent the very thing you describe above, that in a lot of cases victims are shocked or threatened into silence so in those cases if the police (the prosecutor) thinks he/she has enough to make a case, they must press charges.
This is exactly what patents are. You can't patent a car. You can't patent a gas. You can, however, patent the process used to make the car. Or patent a part of the car that functions in a certain way. The important point here is that a patent is not the same as a copyright. If you write a software, your code is copyrighted by default and no additional action is needed for that. You just make sure your code is marked by your name and the date you wrote it and it is yours (you might find it a tiny bit difficult to make it legally binding, it's tricky with software that can be back-dated and manipulated without trace, sending yourself a copy in registered mail I've heard is no longer a good option).
But if you want to patent something, then that patent must specify not just *what* (if you're patenting something physical) but also *how* you're using it. This means, for example, that it is perfectly legal to use someone elses patent in your patent claim, if you're using it in some new way that the original patent did not specify.
For example, if I create a new kind of potato peeler and write it as "a device for peeling the skin off of potatoes" then someone else may (as far as I understand) patent using the exact same device for peeling apples. That's why it's important to think of as many applications or to be general when describing the patent (I could have written "a device for peeling the skin of any kind of round object with a skin". Then again, the more generally I describe my device, the bigger is the risk that the definition infringes on some existing patent.
I never said that there weren't philosophers arguing the merits of monarchy. I could even personally argue that, or argue that in some cases a dictatorship is a much better form of government than any other. I could argue just about anything, even stuff I don't agree with. I said that unlike Anarchy, especially the kinds that are proposed for a modern human society it is not a dream, a mental exercise that has never been put to practical use in any greater area for any extended length of time. Monarchy has existed *continuously* for those 5000 years you like to cite over and over again, whereas anarchy has only existed for very brief periods of time in very small areas.
First line of "Social Behaviour" in the Wikipedia section on bonobos state:
most studies indicate that females have a higher social status in bonobo society.
So apparently it is not so equal as you make light of. Also, they exhibit their peaceful side in the wild, probably in eareas where resources are abundant. In captivity they have been known to mutilate and bully eachother. This tells me that they are not so natually peaceful as you would like. If you have all the resource you need, it is easy to be peaceful. A social construct is only as strong as it is when it is put under pressure.
I would say that Anarchy as a sociatal construct is not viable because it is so vulnerable. In a world with unlimited resources humans would be capable of living in an equal society without a government to force us to be civilized. But resources are not limited and must be distributed and as such is the case, I am not convinced that humans (or bonobos for that matter) can be trusted to not be selfish when our own survival comes into the equation.
No. Go to yourself and your closest relatives. How much of their time do they spend finding out the opinions on the different political parties that exist in your (their) country? How much do they really know of the decisions that their representatives have made? This should tell you that people are far too busy to make informed decisions about more than a handful (or even just one or two) issues.
Direct democracy will never work because people don't know enough to make the right decision! Representative democracy is always better. But there are many ways to be represented and some ways are better than others.:)
I could say the same thing about monarchism, dictatorships, republican democracy and... oh right EVERY SINGLE POLITICAL IDEA... EVER. I just happen to think it's slightly LESS unviable than THOSE crazy concepts.
No you couldn't. Monarchism (or despotism) is not a philosophical theory. It is the result of what happens when someone uses personal power to control other people. See the man with the big sword? He will kill you if you don't pay him money. Oh, your sword is bigger? Kill him then and take his place.
Anarchy will never "just happen". Anarchy is a political theory. Anarchy would require a lot of people agreeing, setting aside their personal desires for the common good. Not impossible, it's just that a single Hitler, Franco, Stalin, Lenin, Genghis Khan or Mao Tse Tung would wreak havoc in such a society as he would gain backing from people with a self-interested agenda and ultimately the single authoritarian voice would pierce the white noise of the dissenting opinions of the undecided masses.
Actually, the definition of "Anti-social" is to do by direct action or indirect action damage to society. The rich ruling the world is how society works right now, so killing them is indeed anti-social behaviour. But in the same way, if your actions cause a major upheaval of the social structure the definition of what is anti-social may change until killing the rich is no longer deemed anti-social.
I might be wrong, but to me those parts felt ironic. I don't think ve really feels like that, but vis commenting on how the gaming community seem to think in regards to this. Especially if you check what ve has written before.
Just because hamburger restaurants sell a lot of hamburgers doesn't mean every single restaurant in the world has to be a hamburger joint.
This
The console market still exists. It might be true that this market shrinks a bit as some of those console gamers get older and find themselves in a position where they can't just sit down and play their games anymore (I know I play only 5% as much as I did before I got a kid).
Console games do things that Facebook games simply do not. I'm guessing, but there really isn't a Skyrim clone on Facebook, right? Or Mass Effect? Or Deus Ex? Bioshock? I'm not saying these games are better than anything you can find on Facebook, Android or iOS. I'm saying it's different and speaks to a different market that likes that sort of thing. You can't just replace the one with the other. And a tiny iPad screen will never replace my console gaming TV.
The solution is to lie about everything in your Facebook profile. Wrong home town, wrong school (use ACME High School or something like that obviously not true). No one at Facebook has the time to check whether the information is correct, but if you leave it blank they can get it elsewhere.
Only if you believe that this tweaking is intentional and "evil". I believe that most of the errors produced in modern science rather stems from "groupthink" and from the subconcious need to produce the results that we are looking for. It is a growing problem that has been identified in recent times.
Also, I don't trust the "adjustments" without having read papers proving those adjustments do not affect the results. One should never trust anything without good reason.
I haven't seen this data, but I believe that the data you refers to is the already filtered data, no? The data where they removed some stations that did not "fit with their data". Without you pointing to exactly where the data is, I don't think I'll be able to find it so if you know where it is, please do tell.
The wikipedia article lists some sources and even a combined study that has looked at 31 studies made. http://en.wikipedia.org/wiki/Electromagnetic_hypersensitivity They very diplomatically concludes that it is very "difficult to find any link between electromagnetic fields and symptoms". Which I find to mean that the research shows that there is none.
First, if you look at the attractor given, that is a huge area where the attractor exists. This could mean the difference between global warming and global cooling. So, your attractors won't save your model (I know that's just an example and that neither you nor I know what the input data does to the climate models we are discussing, but I'm certain that even small changes to the input values will change the outcome a lot, since they keep modifying their model each year that new data arrives).
Averages also aren't a good way, especially if you are not looking at the correct data. This is one of those things that confuse and infuriate people about the climatologists and their results, they just won't produce their data. This is not an unreasonable request. When I did my thesis I provided everything about my thesis in the report, including the software I had used and the data I based my conclusions on. This is so that someone reading it can actually check my results, which is just good science.
Except it does, if you read it (your article). And other sources have quoted the same material differently, so maybe the truth lies somewhere inbetween their reporting.
And even in the article you refer to, the author recognizes that this is interesting research and that they may be right. I find it interesting, however, that he refers to them as "some scientists at CERN" when the proposal for he experiment comes from Henrik Svensmark and that the theory they are testing is his.
But again, he is persona non grata because of what his theory would mean to global warming doctrine, so let's just keep him out of it.
Also, the most interesting point of Svensmarks theory is that he is not at all saying that human beings can't heat up the planet he is just saying that the sun has a hell of a lot to do with our climate too, a lot more than the current models take into account, which was the point I was trying to make.
I'm sorry, but climate modelling is not well understood. Henrik Svensmark's theory that the stars (and the sun, which is a star:)) are controlling the cloud coverage goes against the prevailing models, yet they are turning out to be true. See the C.L.O.U.D. project which just finished at CERN. It is interesting that this result was not mentioned anywhere on slashdot. This is exciting research, provable theories are being proven. This is science, not opinion.
Unfortunately, you are still trying to estimate what is happening 40-100 years in the future, and we fall straight back into chaos theory and the same problems as weather forecasting.
There is no scientific debate on this issue. It's settled.
And once upon a time all scientists knew that the earth was flat. Just because there is a consensus doesn't mean that they are right. I think people are being sceptical because we're just not seeing the evidence of what they are proposing. So far, none of the climatologists predictions have come true. Al Gore himself has bought San Fransisco-bay area real-estate that would be washed away if his own predictions were true.
Even if there are a million scientists that claim that the air is full of little invisible fairies that push the clouds around, if they are scientists, they should listen when someone puts forward proof that this is not the case. There are scientists (Henrik Svensmark, for example) that have alternative theories to why there is global warming and who actually have experiments that confirm their theories.
I think one of the main reasons why people are sceptical to this research is that it is a field where we suck. We suck at predicting weather. We suck at it because it is too hard. If you've studied just a little bit of chaos theory you know that it is impossible to forecast weather for more than a very limited time. So all one can say about it is possibly general and broad statements about how it's going to be in the far future and even then just a slight change in the model or the data you're basing your calculations on and that all changes.
Re:My tips on filtering e-mail spam
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Whatever works for you. This works for me.
My tips on filtering e-mail spam
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I find that spam rarely have my e-mail address in the recipient list, so I simply filter out any e-mail that does not have my e-mail addy there.
Plus I filter out any e-mail from hotmail.com or microsoft.com. That worked better before.
See here. Now you're being more reasonable, even though you're not admitting that I also could be right. We just don't know enough.
I didn't claim any authority, and if it seemed like it, that was surely not my intention. My first post, from which all this stems, merely points out that I thought that perhaps the shoes could be damaging to the legs if used for a long time (which I also pointed out was not intended).
Your example only illustrates what I said. You yourself say that energy is transmitted into the brick and also from the brick into the ground, by friction. Energy is transmitted. But also, in some sense, the energy is constant. The kinetik energy of the brick does not increase.
If I use terms that seem unfamiliar to you, or even wrong, please consider that I am Swedish and that there is a certain language barrier here.
Well, as much as I've enjoyed our discussion maybe we can put it to rest. You can have the last word if you wish.:)/Daniel
Upon some afterthought this is obviously P as in pressure and v as in volume, though where I learned thermodynamics we used small letters for pressure and large for volume. A simple point I know, but it is 8am here and I guess my physics don't work too well before breakfast.
I did my whole calculation again and arrived at the new peak thrust of F=57kN (with your constants and your function pV^k=C.
What I think is that without pen and paper and being able to discuss our calculations in person, we're not going to be able to resolve this satisfactory.
P*v^k In your post you explain k. But what is P and v. I can't find your equation in my thermodynamics book, but I'm assuming you didn't pull it out of thin air and that it is applicable. I'm actually interested to know what it is.
Hey, you're probably right. I haven't studied combustion theory and I've never liked thermodynamics. So you are running rings around me, but you're also not a very nice person, you keep attacking me personally, quite unneccesarily.
I studied nuclear physics and quantum physics and most recently, solid state physics. Also, it is a masters degree which means that I studied a lot of things. The main direction being physics.
When you are standing still, yes there is a force on your foot from below. But your body is exerting the exact same force on the ground, which means that the sum of forces is zero. Energy is only transmitted in an unstable system where the sum of forces is not zero. So, I am in fact right.
If you're sitting down and then stand up, your legs will have the same energy, but your body will recieve energy from them because you are moving your body from a lower position to a higher one, recieving a higher potential energy. This illustrates quite clearly that the energy, kinetik or potential, of the legs is not the same as a kinetik or potential energy of the body (torso).
Now, once again you touch on something I said in my earlier post, that we do not know enough about the invention to have this discussion. Since you have admitted this, maybe we can drop it now. I admit that you know more about combustion and thermodynamics than me (not very hard, I don't know much in those areas) and I admit that there could be a way that the shoes could be only mildly concussive.
I'll be interested to see if you can admit that I could be right.
I've studied physics for 6 years, so I know physics, OK? You explained yourself in your little essay exactly what I meant. Forces are transmittors of energy. You cannot apply a force to anything without also transferring energy. Energy is inheritly indestructible and the only way to transfer energy is by applying force of some kind. This is also rudimentary physics. I know you grasp this concept so I must conclude that you chose to refuse to understand what I said.
While your explanation is quite sound, it still does not answer the main gist of my argument, that the piston is powered by a combustion. It's not a question of evenly pumping in air in a pneumatic piston, it's a small explosion. Does this sound like an even accelleration to you?
Also, consider that even quite normal forces can easily damage your body if they are applied repeatedly and mechanically.
Attacking me personally was quite unneccesary, specially since the fault was not with me or my argument. Energy is not automatically distributed in a system upon entering it, it must travel through it by use of forces, much as you state in your own post. I was not confusing anything, I was waiting for you to understand what I meant.
What I'm saying is that the energy from the combustion is quickly transferred to the leg via the piston and quite violently "shoots" you off the ground. What I'd like from you now, is an explanation as to why you think this is not true. How is the combustion transferred so evenly to the leg?
Lets consider the combustion an ideal one. I never liked thermodynamics much but let's take a look.
p*V=n*R*T, this is the law of an ideal gas. The cylinder has an inside area of A and the piston's distance from the bottom of the cylinder is h. This gives us the force on the piston by the gas in the cylinder as F=p*A, where p=pressure (N/m^2). If we insert this into the formula, we get F*V/A=n*R*T => F*h=n*R*T => F=n*R*T/h. So, if we consider the time it takes for the fuel to combust much shorter than the time it takes for the piston to complete its cycle (not unreasonable) we get that the force on the body is inversely proportional to the length the piston has ejected. This means that we do indeed not have a uniform force working on the leg throughout the step but indeed that the force weakens. Note that h>0 (since the piston never reaches the bottom of the cylinder).
Let's assume that the energy transferrance is 100% (not possible, there is a theoretical limit, but I don't care, because all my calculations so far are very idealised). Let the piston work over the length l, between x and x0. This give us the energy W=n*R*T*ln(x/x0). We see now also that the energy only increases logarithmically with the height of the cylinder. To make me jump straight up half a meter (a little less than two feet, and this is not counting where I am when the pistons are at rest before combustion) we need an energy of W=m*g*0.5 Nm. Together with our earlier formula we get n*R*T*ln(x/x0)=m*g*0.5. We assume that the piston is 1 foot long (in the article), that is 0.3m. We have n*R*T=m*g*0.5/ln(x/x0). We now assume that the expansion in the piston is isoterm (that the temperature doesn't change during the expansion). This might not be entirely right, but what the heck, I just want some rough numbers to work with here (or rather, prove that I know physics). This means that F*h=m*g*0.5/ln(x/x0). Lets examine F when h=x0, at the pistons lowest point. F=m*g*0.5/ln(x/x0)/x0. Let's say that x0=0.05m (5 cm), m=70kg and g=10m/s^2. F=70*10*0.5/ln(0.3/0.05)/0.05=12.5kN. This gives the same person an accelleration of 179m/s^2, which is about 18G.
Considering that the combustion not is instantaneous, that the expansion is not isotermic, that energy transfer is not 100% and so on and so forth, I have proved very little else than that I do know physics and that this is tricky stuff.
I apologize for any mistakes above, since I had to go through the calculation and change variables a few times.
The main point of the calculation above was to prove that the force is not uniformly applied during the extension of the piston, that I think, at least is certain.
The physics involved above is certainly not first semester physics.
Hmm. Well. Seems you struck a soft spot there.:) Maybe I overdid it a bit...
Slashdot Mirror
What is the proper way to apologize for smearing rape victims?
By apologizing. Sorry, but that's all he can do.
But that's not my point. Last I heard of the case, the girls never pressed charges against him. They merely wanted to have him tested for VD. The prosecutor pressed charges (as they must do under Swedish law) when she (because I think it was a she?) heard their story.
The prosecutor thinks there is a rape case here. Whether a rape has actually taken place is now up to the courts (since the girls themselves have not wanted to press charges for rape we can't really say there was a rape at all until that has been established in court).
This system is in place to prevent the very thing you describe above, that in a lot of cases victims are shocked or threatened into silence so in those cases if the police (the prosecutor) thinks he/she has enough to make a case, they must press charges.
This is exactly what patents are. You can't patent a car. You can't patent a gas. You can, however, patent the process used to make the car. Or patent a part of the car that functions in a certain way. The important point here is that a patent is not the same as a copyright. If you write a software, your code is copyrighted by default and no additional action is needed for that. You just make sure your code is marked by your name and the date you wrote it and it is yours (you might find it a tiny bit difficult to make it legally binding, it's tricky with software that can be back-dated and manipulated without trace, sending yourself a copy in registered mail I've heard is no longer a good option).
But if you want to patent something, then that patent must specify not just *what* (if you're patenting something physical) but also *how* you're using it. This means, for example, that it is perfectly legal to use someone elses patent in your patent claim, if you're using it in some new way that the original patent did not specify.
For example, if I create a new kind of potato peeler and write it as "a device for peeling the skin off of potatoes" then someone else may (as far as I understand) patent using the exact same device for peeling apples. That's why it's important to think of as many applications or to be general when describing the patent (I could have written "a device for peeling the skin of any kind of round object with a skin". Then again, the more generally I describe my device, the bigger is the risk that the definition infringes on some existing patent.
Heh. Had forgot about that sig. I can't see it myself (and it took me a while even to find it in my settings). :)
I never said that there weren't philosophers arguing the merits of monarchy. I could even personally argue that, or argue that in some cases a dictatorship is a much better form of government than any other. I could argue just about anything, even stuff I don't agree with. I said that unlike Anarchy, especially the kinds that are proposed for a modern human society it is not a dream, a mental exercise that has never been put to practical use in any greater area for any extended length of time. Monarchy has existed *continuously* for those 5000 years you like to cite over and over again, whereas anarchy has only existed for very brief periods of time in very small areas.
First line of "Social Behaviour" in the Wikipedia section on bonobos state:
most studies indicate that females have a higher social status in bonobo society.
So apparently it is not so equal as you make light of. Also, they exhibit their peaceful side in the wild, probably in eareas where resources are abundant. In captivity they have been known to mutilate and bully eachother. This tells me that they are not so natually peaceful as you would like. If you have all the resource you need, it is easy to be peaceful. A social construct is only as strong as it is when it is put under pressure.
I would say that Anarchy as a sociatal construct is not viable because it is so vulnerable. In a world with unlimited resources humans would be capable of living in an equal society without a government to force us to be civilized. But resources are not limited and must be distributed and as such is the case, I am not convinced that humans (or bonobos for that matter) can be trusted to not be selfish when our own survival comes into the equation.
No. Go to yourself and your closest relatives. How much of their time do they spend finding out the opinions on the different political parties that exist in your (their) country? How much do they really know of the decisions that their representatives have made? This should tell you that people are far too busy to make informed decisions about more than a handful (or even just one or two) issues.
Direct democracy will never work because people don't know enough to make the right decision! Representative democracy is always better. But there are many ways to be represented and some ways are better than others. :)
I could say the same thing about monarchism, dictatorships, republican democracy and ... oh right EVERY SINGLE POLITICAL IDEA... EVER.
I just happen to think it's slightly LESS unviable than THOSE crazy concepts.
No you couldn't. Monarchism (or despotism) is not a philosophical theory. It is the result of what happens when someone uses personal power to control other people. See the man with the big sword? He will kill you if you don't pay him money. Oh, your sword is bigger? Kill him then and take his place.
Anarchy will never "just happen". Anarchy is a political theory. Anarchy would require a lot of people agreeing, setting aside their personal desires for the common good. Not impossible, it's just that a single Hitler, Franco, Stalin, Lenin, Genghis Khan or Mao Tse Tung would wreak havoc in such a society as he would gain backing from people with a self-interested agenda and ultimately the single authoritarian voice would pierce the white noise of the dissenting opinions of the undecided masses.
Actually, the definition of "Anti-social" is to do by direct action or indirect action damage to society. The rich ruling the world is how society works right now, so killing them is indeed anti-social behaviour. But in the same way, if your actions cause a major upheaval of the social structure the definition of what is anti-social may change until killing the rich is no longer deemed anti-social.
The french did that in 1790.
I might be wrong, but to me those parts felt ironic. I don't think ve really feels like that, but vis commenting on how the gaming community seem to think in regards to this. Especially if you check what ve has written before.
Just because hamburger restaurants sell a lot of hamburgers doesn't mean every single restaurant in the world has to be a hamburger joint.
This
The console market still exists. It might be true that this market shrinks a bit as some of those console gamers get older and find themselves
in a position where they can't just sit down and play their games anymore (I know I play only 5% as much as I did before I got a kid).
Console games do things that Facebook games simply do not. I'm guessing, but there really isn't a Skyrim clone on Facebook, right? Or Mass Effect? Or Deus Ex? Bioshock? I'm not saying these games are better than anything you can find on Facebook, Android or iOS. I'm saying it's different and speaks to a different market that likes that sort of thing. You can't just replace the one with the other. And a tiny iPad screen will never replace my console gaming TV.
The solution is to lie about everything in your Facebook profile. Wrong home town, wrong school (use ACME High School or something like that obviously not true). No one at Facebook has the time to check whether the information is correct, but if you leave it blank they can get it elsewhere.
Only if you believe that this tweaking is intentional and "evil". I believe that most of the errors produced in modern science rather stems from "groupthink" and from the subconcious need to produce the results that we are looking for. It is a growing problem that has been identified in recent times.
Also, I don't trust the "adjustments" without having read papers proving those adjustments do not affect the results. One should never trust anything without good reason.
But thanks for the link. I'll check it out.
I haven't seen this data, but I believe that the data you refers to is the already filtered data, no? The data where they removed some stations that did not "fit with their data". Without you pointing to exactly where the data is, I don't think I'll be able to find it so if you know where it is, please do tell.
The wikipedia article lists some sources and even a combined study that has looked at 31 studies made.
http://en.wikipedia.org/wiki/Electromagnetic_hypersensitivity
They very diplomatically concludes that it is very "difficult to find any link between electromagnetic fields and symptoms". Which I find to mean that the research shows that there is none.
First, if you look at the attractor given, that is a huge area where the attractor exists. This could mean the difference between global warming and global cooling. So, your attractors won't save your model (I know that's just an example and that neither you nor I know what the input data does to the climate models we are discussing, but I'm certain that even small changes to the input values will change the outcome a lot, since they keep modifying their model each year that new data arrives).
Averages also aren't a good way, especially if you are not looking at the correct data. This is one of those things that confuse and infuriate people about the climatologists and their results, they just won't produce their data. This is not an unreasonable request. When I did my thesis I provided everything about my thesis in the report, including the software I had used and the data I based my conclusions on. This is so that someone reading it can actually check my results, which is just good science.
Except it does, if you read it (your article). And other sources have quoted the same material differently, so maybe the truth lies somewhere inbetween their reporting.
And even in the article you refer to, the author recognizes that this is interesting research and that they may be right. I find it interesting, however, that he refers to them as "some scientists at CERN" when the proposal for he experiment comes from Henrik Svensmark and that the theory they are testing is his.
But again, he is persona non grata because of what his theory would mean to global warming doctrine, so let's just keep him out of it.
Also, the most interesting point of Svensmarks theory is that he is not at all saying that human beings can't heat up the planet he is just saying that the sun has a hell of a lot to do with our climate too, a lot more than the current models take into account, which was the point I was trying to make.
I'm sorry, but climate modelling is not well understood. Henrik Svensmark's theory that the stars (and the sun, which is a star :)) are controlling the cloud coverage goes against the prevailing models, yet they are turning out to be true. See the C.L.O.U.D. project which just finished at CERN. It is interesting that this result was not mentioned anywhere on slashdot. This is exciting research, provable theories are being proven. This is science, not opinion.
Unfortunately, you are still trying to estimate what is happening 40-100 years in the future, and we fall straight back into chaos theory and the same problems as weather forecasting.
There is no scientific debate on this issue. It's settled.
And once upon a time all scientists knew that the earth was flat. Just because there is a consensus doesn't mean that they are right. I think people are being sceptical because we're just not seeing the evidence of what they are proposing. So far, none of the climatologists predictions have come true. Al Gore himself has bought San Fransisco-bay area real-estate that would be washed away if his own predictions were true.
Even if there are a million scientists that claim that the air is full of little invisible fairies that push the clouds around, if they are scientists, they should listen when someone puts forward proof that this is not the case. There are scientists (Henrik Svensmark, for example) that have alternative theories to why there is global warming and who actually have experiments that confirm their theories.
I think one of the main reasons why people are sceptical to this research is that it is a field where we suck. We suck at predicting weather. We suck at it because it is too hard. If you've studied just a little bit of chaos theory you know that it is impossible to forecast weather for more than a very limited time. So all one can say about it is possibly general and broad statements about how it's going to be in the far future and even then just a slight change in the model or the data you're basing your calculations on and that all changes.
Whatever works for you. This works for me.
I find that spam rarely have my e-mail address in the recipient list, so I simply filter out any e-mail that does not have my e-mail addy there. Plus I filter out any e-mail from hotmail.com or microsoft.com. That worked better before.
I didn't claim any authority, and if it seemed like it, that was surely not my intention. My first post, from which all this stems, merely points out that I thought that perhaps the shoes could be damaging to the legs if used for a long time (which I also pointed out was not intended).
Your example only illustrates what I said. You yourself say that energy is transmitted into the brick and also from the brick into the ground, by friction. Energy is transmitted. But also, in some sense, the energy is constant. The kinetik energy of the brick does not increase.
If I use terms that seem unfamiliar to you, or even wrong, please consider that I am Swedish and that there is a certain language barrier here.
Well, as much as I've enjoyed our discussion maybe we can put it to rest. You can have the last word if you wish. :) /Daniel
I did my whole calculation again and arrived at the new peak thrust of F=57kN (with your constants and your function pV^k=C.
What I think is that without pen and paper and being able to discuss our calculations in person, we're not going to be able to resolve this satisfactory.
P*v^k
In your post you explain k. But what is P and v. I can't find your equation in my thermodynamics book, but I'm assuming you didn't pull it out of thin air and that it is applicable. I'm actually interested to know what it is.
I studied nuclear physics and quantum physics and most recently, solid state physics. Also, it is a masters degree which means that I studied a lot of things. The main direction being physics.
When you are standing still, yes there is a force on your foot from below. But your body is exerting the exact same force on the ground, which means that the sum of forces is zero. Energy is only transmitted in an unstable system where the sum of forces is not zero. So, I am in fact right.
If you're sitting down and then stand up, your legs will have the same energy, but your body will recieve energy from them because you are moving your body from a lower position to a higher one, recieving a higher potential energy. This illustrates quite clearly that the energy, kinetik or potential, of the legs is not the same as a kinetik or potential energy of the body (torso).
Now, once again you touch on something I said in my earlier post, that we do not know enough about the invention to have this discussion. Since you have admitted this, maybe we can drop it now. I admit that you know more about combustion and thermodynamics than me (not very hard, I don't know much in those areas) and I admit that there could be a way that the shoes could be only mildly concussive.
I'll be interested to see if you can admit that I could be right.
While your explanation is quite sound, it still does not answer the main gist of my argument, that the piston is powered by a combustion. It's not a question of evenly pumping in air in a pneumatic piston, it's a small explosion. Does this sound like an even accelleration to you?
Also, consider that even quite normal forces can easily damage your body if they are applied repeatedly and mechanically.
Attacking me personally was quite unneccesary, specially since the fault was not with me or my argument. Energy is not automatically distributed in a system upon entering it, it must travel through it by use of forces, much as you state in your own post. I was not confusing anything, I was waiting for you to understand what I meant.
What I'm saying is that the energy from the combustion is quickly transferred to the leg via the piston and quite violently "shoots" you off the ground. What I'd like from you now, is an explanation as to why you think this is not true. How is the combustion transferred so evenly to the leg?
Lets consider the combustion an ideal one. I never liked thermodynamics much but let's take a look.
p*V=n*R*T, this is the law of an ideal gas. The cylinder has an inside area of A and the piston's distance from the bottom of the cylinder is h. This gives us the force on the piston by the gas in the cylinder as F=p*A, where p=pressure (N/m^2). If we insert this into the formula, we get F*V/A=n*R*T => F*h=n*R*T => F=n*R*T/h. So, if we consider the time it takes for the fuel to combust much shorter than the time it takes for the piston to complete its cycle (not unreasonable) we get that the force on the body is inversely proportional to the length the piston has ejected. This means that we do indeed not have a uniform force working on the leg throughout the step but indeed that the force weakens. Note that h>0 (since the piston never reaches the bottom of the cylinder).
Let's assume that the energy transferrance is 100% (not possible, there is a theoretical limit, but I don't care, because all my calculations so far are very idealised). Let the piston work over the length l, between x and x0. This give us the energy W=n*R*T*ln(x/x0). We see now also that the energy only increases logarithmically with the height of the cylinder. To make me jump straight up half a meter (a little less than two feet, and this is not counting where I am when the pistons are at rest before combustion) we need an energy of W=m*g*0.5 Nm. Together with our earlier formula we get n*R*T*ln(x/x0)=m*g*0.5. We assume that the piston is 1 foot long (in the article), that is 0.3m. We have n*R*T=m*g*0.5/ln(x/x0). We now assume that the expansion in the piston is isoterm (that the temperature doesn't change during the expansion). This might not be entirely right, but what the heck, I just want some rough numbers to work with here (or rather, prove that I know physics). This means that F*h=m*g*0.5/ln(x/x0). Lets examine F when h=x0, at the pistons lowest point. F=m*g*0.5/ln(x/x0)/x0. Let's say that x0=0.05m (5 cm), m=70kg and g=10m/s^2. F=70*10*0.5/ln(0.3/0.05)/0.05=12.5kN. This gives the same person an accelleration of 179m/s^2, which is about 18G.
Considering that the combustion not is instantaneous, that the expansion is not isotermic, that energy transfer is not 100% and so on and so forth, I have proved very little else than that I do know physics and that this is tricky stuff.
I apologize for any mistakes above, since I had to go through the calculation and change variables a few times.
The main point of the calculation above was to prove that the force is not uniformly applied during the extension of the piston, that I think, at least is certain.
The physics involved above is certainly not first semester physics.
Hmm. Well. Seems you struck a soft spot there. :) Maybe I overdid it a bit...