studiot

I can't say if this was addressed to my post 38, immediately following post 37 that you addressed in your previous paragraph. However if you can't or won't discuss then you have no business posting here. I suggest you read the rules.

What connection are you making between the title of this thread and the question you seem to have asked at the end? Are you going to offer any reason why natural and human generated effects should be mutually exclusive?

Then explain how the stated rules allow the conditions I have described. "I think .... must be...." does not cut it. You have not replied to my comment about the uncertainty principle, have you given up on that?

Why does this not contradict this definition Further if there are only a finite number of noktons how can intermediate and in particular irrational values of measure be achieved? Edit spelling.

I don't follow. Yes, Heisenberg's application is not the only application of the uncertainty principle. Its effects are normally insignificant in the macro world (larger than atoms). He was the first to apply it to the micro sub atomic world where it is hugely significant. Do you understand where it comes from? Once you see the connection between the mathematics and the real world it really is very simple and beautiful.

Do I conclude from the diatribe in your post 43 that I am wasting my time offering an opinion, or additional discussion points?

Well it seems to me that the paper contains a self contradiction since in the opening discussion it restricts the scope of the theory to rational numbers, but then goes on to discuss Euclidian norms, which use the square root. Can you throw any light on this? By this I assume you mean the Heisenberg uncertainty principle, which is inherent in the pure mathematics of the operators involved and does not really present a problem.

Taking the physics route may be more personally satisfying, given your interest list. But it will cut you out of the Chartered status avaiable to engineers, and the higher career potential that offers.

This is my first reading of this thread and I wonder why it is so narrowly focused. The discussion seems to concentrate on absolutes. What about the use of statistics in scientific testing? And what exactly is meant by 'scientific testing' Would analysis of blood samples be included? What safe working load certification testing? Is there any data on what distribution of testing activity between various motivations?

+1

I am going to guess (I don't know the book) that your question should read How thick this does the plate have to be if granite fails in tension at 20 MPa? Assume density is 2700 kg m^3. Since no further information is provided (about the plate dimensions or tother loadings) I am further going to guess that you are meant to analyse the plate as a series of 1metre wide strips. That will give you a volume and therefore a uniformly distributed load on each strip. You can thus calculate the maximum bending stress in the middle. This stress can be related to the horizontal tension and compression (shearing stress) distribution at that section by the usual 'bending equation' which will give you a value for the half-depth. This is homework help so show us how you get on with this information and see if more help is required. Don't just pick equations at random from the book, have a good reason for choosing. Edit: I thought someone had asked this before and I see that was about this time last year, but the OP never came back. http://www.scienceforums.net/topic/86844-problem-314-turcotte-and-schubert-geodynamics/ We can certainly help you understand the problem so that you can arrive at the correct answer, what was the difficulty with the answer given in that thread?

There are many differences and also many similarities. Some are big and significant, some or small and insignificant. But there are no clear cut boundaries as you can always find examples of one aspect in the other. I will just highlight one particular difference. It is quite a different matter to measure, observe and deduce what is already there (as scientists usually do) than start with nothing and place (create) some defined thing or system (as engineers usually do). For example measuring the size, disposition and gravitational pull etc of an existing mountain as opposed to placing one to some specification. However with my comment on no clear boundaries in mind, scientists have done just that when completing the catalogue of elements in the periodic table or the catalogue of elementary particles in particle physics.

Yes 'gas' explosions can be quite devastating. Was the one in your picture a faulty appliance explosion or a collected gas explosion? Do you know the % of each type? The somewhat adversarial nature of this discussion is bringing out some valuable points. That's quite a short lead. Do you have sockets (wall*?* outlets) up near the ceiling in America? Here is a (smoke I think) detector plugged into a normal pendant light fitting. The 'bulb' is then plugged into it.

How long would the battery last in such a detector?

Actually jaj russel asked about kg weight (which is a unit of weight). Weight is the force of gravity exerted on a mass so is a force. Force = mass x acceleration So if we rearrange this we have mass = Force / acceleration. So the mass in mass units of 80kg weight is 80/g or approx 80/10 = 8 kg mass https://en.wikipedia.org/wiki/Kilogram-force

I'm sure that there are many mehtods of monitoring combustible gases. But how do you know that the gas you are 'monitoring' is what you think it is and not particulates/water vapour/something else entirely? When I did my confined spaces training we covered a lot of explosion risks. The importance of a confined space in the lead up to an explosion cannot be overstressed. Fuel gases disperse too quickly in the open air to explode.

No. This is a Newtonian statement, not a multidimensional spacetime one. And it requires a Newtonian explanation. Prior to falling off the building, high or low, the object is not moving. So the first question is "Why did the apple fall at all" Or in any system of mechanics what causes movement or under what conditions does movement occur?

Take a deep breath and Smile. Gas detectors use radioactivity to perform the detection. You like engineering so you should read this. https://en.wikipedia.org/wiki/Flammability_limit You are correct that the main danger is that of explosion since modern gas supplies are not poisonous. However you since light gases are employed (supplied) an explosion requires a collection zone or they will disperse. You should therefore place the detector(s) in likely collection zones at height where there is no outlet for these gases.

My comment had nothing to do with radon. How do you think gas detectors work? Meahwhile what do you think is the danger from gas supplies leaking gas?

Having overfitted gas detectors, are you also fitting a radiation detector?

Both classical and statistical thermodynamics are founded on the idea of the state of a system. Order and disorder are not really scientific terms they are populist words. Order has no meaning at all in classical terms. In statistical terms it simply means that you can take any one of the possible states a system may adopt and declare that to be order. Every other state by definiition is therefore disorder. Of course, rather like choosing a suitable origin to make calculations easy, we select the most convenient state to call our base order. Numerical calculations for thermodynamic transitions are only possible if the beginning and end states are completely known, but it is not always possible to know the thermodynamic state of a system. Whilst you are checking the definitions of the word state, it would be a good idea to include other thermodynamic terms you are chucking about. An open system allows exchange of matter and energy with the surroundings. A closed system allows exchange of energy but not matter. Other useful terms to check include Energy, Entropy, System, System boundary, Surroundings, System Variables. Finally you have not answered my first question Are you wrinting an essay? This is not an idle question, just that it would be useful for those trying to help to understand the purpose of your thoughts since you are not using technical terms correctly.

I note you said the fire engine rolled. You should also discuss the effect of the height of the centre of gravity of your trucks with your colleagues These videos and resources about the tilt test for London buses may be useful. You can safely tilt a London double decker bus to 30o. https://www.google.co.uk/search?hl=en-GB&source=hp&biw=&bih=&q=london+bus+tilt+test&gbv=2&oq=tilt+london+bus&gs_l=heirloom-hp.1.0.0i22i30l2.3703.7171.0.10937.15.15.0.0.0.0.141.1766.2j13.15.0....0...1ac.1.34.heirloom-hp..0.15.1766.c-MnOItnt6I

LaTex or MathML, which is similar, are all very well but the most common phrase here and on most technical sites is Did you draw a diagram? and you can't do this or include a graphic in Tex or MathML. Anyway here are some free (online) resources: To build up maths expressions by picking from a list https://www.codecogs.com/latex/eqneditor.php or http://www.sciweavers.org/free-online-latex-equation-editor You can create the expression and produce either a gif graphic or actual LaTex code to place on a page. To make simple maths drawings algebraic formulae, use tables, spreadsheets and stuff https://www.geogebra.org/

I did a design for one of these once. +1

20km/s is not really fast compared to the speed of light so why did you mention mass gain? There is no mass gain, regardless of speed or acceleration under classical (Newtonian) mechanics. The object will only accelerate whilst there is a force acting on it. Remember that a deceleration is considered as a negative acceleration and that change of direction without change of speed is also an acceleration. There is further information in your other post. So to recap, this is a discussion in classical mechanics, perhaps about a meteor or asteroid?