Bender

Wikipedia has a list of computer limits.

Could you source how much energy you need to get the D and T compared to the energy output? How big a concern is this?

Hopefully, you won't die unhappy when it isn't

Difference in thermal expansion on 75 mm for a moderate 100°C increase in themperature is 75x10^-5*100=75 µm, which is plenty to go from a loose fit (eg H7/h6) to a tight fit (eg H7/s6) (or vice versa). The first is mountable by hand or with a little force, the second is very difficult to assemble/disassemble without temperature change.

I don't think there is a consensus about the quantisation of time or space (although there are hypotheses that introduce such quantisation). If space is not quantised, photons do not take "steps". Even if it is, a photon would be spread out over multiple "steps" and it would be hard to pinpoint it to a specific "step". Moreover, if there are steps, we don't know whether they are indeed a Planck length long. If time is continuous, which as far as I know is still the main view, talking about "real seconds" in the meaning you imply, is pointless. I am no expert however, so someone else might step in and correct me. I can answer the question in the title: there are [math]1.9 \cdot 10^{43}[/math] Planck Times in one second.

I don't know if guns come with a warranty, which guarantees a certain life time. I guess that is difficult, because you cannot prove to have fired a certain amount of bullets. For other products, there are consumer organisations or magazines that test different products and compare them with their specs. I guess they should exist for guns in the US too. Then there is the market effect: if the barrels consistently last less long than the manufacturers claim, nobody is going to buy their stuff. You can look for reviews of other customers. Given the popularity of guns in the US, I expect a lot of info can be found online and in magazines. The main trick is discerning which information is coloured by marketing.

Usually life time comes with a probability: e.g. 95% of the samples will last that long. I don't know about guns.

Perhaps. However, energy demand of India and China will increase dramatically in the future. China has already proven to be quite efficient in building massive infrastructure very quickly. If they decide to go for it, they can do it on their own. They also don't suffer from politics or public opinion. An important question will be whether the human race will be able to limit their energy consumption in the future in such a way that it can all be produced with renewable sources. If e.g. the entire world population decides to buy an electric car, including those in developing countries that don't currently own a car, then we would need quite a lot more electricity. I guess we'll see in 50 years.

Yes. It obviously went wrong sometimes. Hundreds have died under collapsing churches during construction.

It may be wishful thinking from me. Perhaps as fossile fuels run out, political hurdles might get easier to overcome. If ITER is a success, I wouldn't be surprised if e.g. China decides to build one in a very short time.

Well, my prediction is more like 30-35 years, so we seem to be closing in slightly.

What do you mean by "the rate of spin is restored"? The point of a despin device is that there is an energy transfer from the centre to the extended weights. There is no energy increase, but a decrease in kinetic energy (the difference goes to heat). Even if you are unable to do the math, you can understand this by sitting on a rotating chair with some weights in your hands: if you have someone rotate you, it takes effort to pull the weights towards you, but letting them stretch your arms is easy. What's up with the blurry picture? Also: evidence, please. Fuzzy ideas aren't evidence.

ITER is currently being built and should be ready for experiments by 2025. It will be the first nuclear fusion facility to produce more energy than it consumes. As is usual for such big projects, I guess you can probably add a couple of years before it is actually ready . After that, the road should be clear to build another which can actually generate electricity, which will probably take another decade or two.

You could look at it as two opposite poles of magnets attracting and two similar poles repelling. In the case of an electromotor, one or both of the magnets are replaced by elektromagnets which can change polarity in different ways.

Of course. e.g. a gps uses it to calculate the estimated time of arrival given the average speed on each road and the length of those roads. When looking at accelerating or breaking of a vehicle, it is often safe to ignore any rotational effects (not always) ... As long as you are aware that this is not a general rule, the frame of reference is an arbitrary choice and that in practical problems, you should look at the relevant time frame. Speedometers can work in several ways. One is magnetic, where the voltage increases with velocity (much like how a dynamo works). Another is with encoders: discs with either optical or magnetic marks. The amount of marks passing a detector is counted to know the distance driven. Divide by time and you have velocity. On a bike, the disk is replaced by a magnet on the wheel, so the speedometer counts the revolutions of the wheel. In the examples, the required force was not measured. It was determined by experience and trial and error what was required for a specific task.

3) I assume that with "x-axis" you mean "t-axis" and are talking about a negative time? In that case, it depends on the question, which should make it clear in which time interval you should look. I would guess in this case they are looking for a positive time, because that is where the local maximum is. 4) instantaneous velocities and accelerations weren't measured . In fact quite often they aren't measured even now and instead derived the position measurement (or position and velocity from the acceleration measurement). As far as I know, Galileo was the first to measure acceleration indirectly by positioning bells in such a way that a passing ball would cause a constant rhythm. It depends of course how far back you want to go. Rotational velocity could be measured with the centripetal force or induced voltage. Force could be measured the same way as it is measured now: deformation of a spring (or elastic structure). I don't really know much about the history of measurement techniques, to be honest. It would probably have depended greatly on the application. Are you looking for anything specific?

Still waiting for evidence. A figure would certainly help to clarify your explanations. In the case of measuring heat losses: why not try it yourself? It is not easy to get very accurate results, however, because the system is not entirely closed. As I said, many, many people have tried to find inconsistencies in conservation of energy, none succeeded. You seem to have the wrong idea about what science is: nothing is accepted without (a lot of) experimental evidence. Yo-yo despin: please provide evidence of your claim. To be honest, I'm not really sure what your claim is, so I cannot comment further on it.

Isn't this false for other massive particles, such as electrons, which also behave as waves? In other words: electrons are waves that move matter, regardless of how you define "move".

We use different parts of our brain for language and mathematics, as brain scans show. Visualisation and number judgement seem to be key. As to how we got from basic math to advanced math: practice. If you practice a skill, you become better at it, especially if you practice as a child. On top of that, better nourishment, health and education for young children also results in better brains, even with the same genes.

Mathematics, cosmology and structural engineering are not products of biological evolution. Homo sapiens hasn't significantly evolved between living in caves and building computers.

1) F=ma is used to relate force with acceleration. When friction is minimised e.g. in a vacuum or on an air table, the heat losses are negligible and the results are extremely accurate (until relativistic effects starts to play, but that isn't really relevant here). 2) heat losses in mechanical system have been carefully measured, and the loss in mechanical energy matches the increase in heat perfectly. The reverse, where heat is converted to mechanical energy has exactly the same relation. There is no "fumbling" going on as you seem to suggest. 3) please explain how Galileo's pendulum proves that. You still haven't provided a single shred of evidence, or even a clear hypothesis.

Conservation of energy seemed to be violated Out of curiosity: are you referring to the formation neutrino's?

More or less. For the pull to be equal in all directions, you would indeed need either an infinite universe or be in the CoG of a finite universe (that is not closed). If you have a finite amount of matter in an infinite space, there are two options: - it is distributed, which means in any finite portion of space there would be no mass - it is located in a specific place, in which case the amount of space there is outside that place is irrelevant, and it might just as well be finite Whether everything would be pulled to the CoG of a finite universe, depends on how fast the matter is moving outwards (at least, IIRC, but someone will surely correct it if it is wrong): - too slow, and it will eventually collapse back to the CoG - too fast, and it will continue to expand forever, because the force decreases faster than it can slow down the matter (in other words, some of the matter is moving faster than the escape velocity of the universe) - just right: it will continue to expand, but always slower to go asymptotically to a fixed size. Of course, it is all just a thought experiment, as we know none of this is actually the case in our universe.

Did you make a typo and meant to say "infinite" amount of mass? Anyway, even an infinite amount of mass wouldn't exert an infinite force, because the distance is also infinite. Also, see point 1) I made.

Sorry, both angular momentum and energy are also conserved. In fact, the easiest way to predict the outcome of two spinning objects colliding is by using these three conservation laws. Of course, some of the energy will be lost to heat, so now you have effectively lost "useful" energy to entropy. A hint: when attempting to break conservation of energy, at least do the math before making claims. A mundane Newtonian mechanical system will always simply follow Newtonian mechanics (even though the math can be quite challenging at times). If you did the math and got energy out the system: you made a mistake. Only new, hypothetical physics could hope to break conservation laws, because nothing in established physics can.