studiot

Can't agree with that. There set of integers is infinite, yet it does not contain an infinite amount of other non integer numbers. Saying there are things unknown or I don't know is no barrier to there being an infinite set of knowledge, separable from other infinite sets of other knowledge. You have already pointed out that is the nature of infinity.

Did you forget to write your own text after pasting in the quotes?

Barfbag, Since you were interested in my last post (#16) I will expand. Firstly the quote as I remember it was due to the builder of one of the NewYork bridges and went An Engineer is someone who can build (make) something for $1 that any fool can build (make) for $2. Which is different from barely standing. As to bridges and their design, the bridge has the longest formal design life of anything made by Man. This design life is 120 years, though some have stood for more than ten times that. When an engineer designs a structure she considers a great many other factors besides what is known as 'The limit state of collapse'. A structural design is judged against a set of limit states to provide "A quantifiable and acceptably low probability of failure against any of these criteria" This method replaced the older 'factor of safety method' of design. Statistics plays an important part in the design. I will explain further if you like. Anyway the most usual failure for structures is not collapse, although that does unfortunately happen as in Tacoma Narrow and Lodden Vaiduct, but failure of what is known as the "limit state of servicability" This means that although the structure does not fall down or become unsafe, the deflection under design load is excessive. A good recent example was the London 'wobbly bridge' that was too flexible https://www.google.co.uk/search?hl=en-GB&source=hp&q=london+wobbly+bridge+video&gbv=2&oq=london+wobbly+bridge&gs_l=heirloom-hp.1.1.0l2j0i22i30l3.828.5594.0.10703.20.18.0.2.2.0.265.2845.0j7j7.14.0....0...1ac.1.34.heirloom-hp..4.16.2922.MoPMxhmZDOk One main purpose of the limit state of servicability is to limit deflection in floors/ceilings so that finishings such as plaster or tiling does not crack.

Relative, I expect this thread will end shortly but please take these thoughts with you to your next question. They are meant in a kind and helpful way to improve your future experiences. Even Strange is not 100% right 100% of the time. But you seem to think you are never wrong. When the discussion gets too difficult you change the subject. That is why you think that no one can understand you. Because they are thinking about the last thing you said, whereas you are thinking about the next thing you are going to say. That is an incredible barrier to communication. So two questions. When was the last time you accepted you were wrong here at SF? How many times have you changed the subject in this thread? All the best in the future.

String Junky Yes, engineers understand quantitatively the limits of the properties of the materials available to them. @String Junky Sometimes. Hopefully more often than not. @Inigo Montoya Having done some failure investigations in my time I have little sympathy for an Engineer who designs a bridge that barely stands. Such a bridge would not satisfy any code that I know of.

But that the original question was not as to whether any body or collection of bodies, human or otherwise, knows this knowledge. The title question was is knowledge infinte? I maintain that since I can add 1 to any number chosen I have access to an infinity of numbers. Therefore there is an infinity of knowledge available, whether I know it or not.

Well said +1

1) Is this your diagram? 2) Why do you think you need the length of XQ? 3) What is the relationship between the areas of similar triangles? : If you don't know look it up. 4) What is your strategy for solving this?

This is true, though I prefer 'means of recording'.

I'm glad you are thinking about that because one of the challenges in numerical mathematics has always been performing larger calculations than will fit into the available computing 'machine' in one go. It is perfectly possible to perform a 20 digit calculation on an 8 digit machine if you know how to divide up the calculation. This can be extended to 'n' digits.

Acceleration is a vector quantity. What I was trying to do was to get you to understand what you were doing so that you could present it in an appropriate way. The final arithmetic is trivial. So if N is the Normal reaction and F the frictional force The mass of 75kg is accelerating down a 25 degree slope. Resolving acceleration perpendicular to the slope Mass x acceleration = 75 x 0 = 75gcos25 - N by Newton’s second Law (Often called N2) Resolving parallel to the slope Mass x acceleration = 75 x 3.6 = 75gsin25 - F by N2 This allows you to properly calculate [math]{\mu _k}[/math] and has the advantage that if you make a mistake you have shown the examiner you know what you are doing so will gain all the available method marks If you work this correctly you will note something interesting about the mass, which means that you do not need to calculate the actual values of the forces. You should get an equation [math]{\rm{acceleration}}[/math] = [math]g\sin \theta [/math] - [math]{\mu _k}g\cos \theta [/math] ie independent of the mass. What value did you make the coefficient of friction? Interestingly this equation also tells us that for the body to slide down the slope [math]\sin \theta [/math] > [math]{\mu _k}\cos \theta [/math] If on the other hand [math]\sin \theta [/math] < [math]{\mu _k}\cos \theta [/math] Then the body will not move. Further the frictional force will be [math]mg\sin \theta [/math] Which is less than the frictional force when moving. That is the full limiting friction is not developed.

This is not favouritism. One practitioner of Mainstream science will (or should) also always ask for evidence from another as well as from others.

Can you prove the claim in your second sentence?

The point is that rigs are so heavy, that once they are in motion, you cannot just stop them and anchor (you probably can't anchor anyway for fear of hitting a pipeline). No one would start off without better position control than a sextant, but once in motion the aim would be to bring the rig to a safe halt if EPS was lost. This would mean monitoring the closing angle between other objects within view. There are always plenty of objects in an offshore oilfield.

When I used to move rigs, we used Decca, Trisponder and Syledis. Occasionally they failed and we had to get the sextant out. Nowadays there is (hopefully) enough redundancy in the GPS system to avoid the need for this. But this is (an interesting) digression from the OP, which was about tides. The need for tidal correction really comes in for marine geodetic surveying work and I was interested to learn if modern technology has managed to remove the need for significant post-fix calculation work.

But unless you know the altitude, you don't know the plan coordinates.

I like this last line from your link, very drole. It's a long time since I moved oil rigs about, but the message seems still to be, don't rely on GPS.

Thank you John. So that means that to determine the depth of water you would have to know the time and tide tables and perform calculation. So it would not be automatic.

Which geoid? Tides go up and down.

It would be so easy to attack when such balderdash is presented, but I will simply enjoin you to use your favourite method of 'thinking about this', before you make such unsupported statements. You have to have a concept of 'noon' before you can employ this method, which means that you have to have a concept of 'Time'. Time was originally measured by the burning of lights, or the dripping of water from a vessel. Cleary (k)not (pun intended). You (and swansont) should also distinguish between solar time and sidereal time. They are different. http://astrosun2.astro.cornell.edu/academics/courses/astro201/sidereal.htm

GPS is a 3D space system, but terrestrial positioning is referred to a chart on some projection or other. That projection is onto some reference surface, but craft a rearely positioned directly on that durface due to marine tides. In the old days we used to have to make a manual correction for this, I wondered if the modern systems have a way of doing this automatically and what this would be. I am not referring to earth tides, which are too slow.

I've been following several discussion between GPS experts(?) and I wondered what GPS does for tidal corrections when the position is reduced to a chart?

Stationary objects can still revolve.

I don't think this has anything to do with the pupils or the teachers, it has to do with declining curriculum standards and present day overreliance on electronic aids.

I haven't done the conversion, but distance has been measured in degrees, minutes and seconds of arc for centuries by navigators, surveyors and astronomers. Relative, if you are referring to this you should say so. In this scheme there is something known as 'The equation of Time', which can also be considered as an equation of distance. But you should not confuse seconds of time with seconds of arc.