Non Electrical/Electronic, but makes you think ! - Page 1
Forum section: electronics / general

author: GlennSprigg
author_rank: Super Contributor
timestamp: December 25, 2017, 12:04:23 pm
content: Imagine an object, thrown/shot upwards, decelerating now due to gravity.Imagine also that this object was theoretically initially moving exactly vertical !!Eventually... at what ever distance, (10 feet, 100 feet, 1000 feet, 'not' outer space!),it is now traveling back down toward the ground...... The hypothesis is that evenwhen it was at the 'top', that it NEVER STOPPED !!!!!!It was either traveling UP, or traveling DOWN, no matter how slow it became at times !!!It was theoretically at 'zero' speed, for ZERO time !!!There is no suspended animation, so it MUST either be going UP or DOWN !!Can you disprove this....Glenn

author: kalel
author_rank: Frequent Contributor
timestamp: December 25, 2017, 12:11:41 pm
content: It's interesting, I personally could not either prove it or disprove it. One way to attempt to get some proof would be measurement, but I don't know of a way that could measure to such degree of accuracy and resolution that it could tell that the object is "absolutely not moving". Also, something will "always" (also cannot guarantee that) be moving inside of the object, and I don't know if the particles that move inside of the object might contribute to a small movement of the entire object.

author: Vtile
author_rank: Super Contributor
timestamp: December 25, 2017, 12:40:32 pm
content: So is zero a zero or infinity small?

author: Rerouter
author_rank: Super Contributor
timestamp: December 25, 2017, 07:06:47 pm
content: To say it never came to rest when approaching the top of the curve is a clearer way to put it.If younthrow an object directly vertical, in the air differential drag will have converted some velocity to a non coherent angle. In a vacuum the rotation of the earth will also add a small vector of apparent velocity.Now lets say we simplify and cheat. You know spherical cows and all that jazz physisists like go do.For the verticle velocity, as there was a direction change. The average velocity of the atoms in the object crossed through 0 atleast once.Its hard to accuratly predict exactly what attosecond that occured. And due to random nature or a small pressecion of rotation the object may have wobbled up and down a very small amount at that threshold making multiple transisions.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 25, 2017, 09:10:49 pm
content: Relevant video:

author: TerraHertz
author_rank: Super Contributor
timestamp: December 25, 2017, 09:21:10 pm
content: Quote from: GlennSprigg on December 25, 2017, 12:04:23 pmYou forgot to specify this experiment must be done on a stationary, non-rotating Earth. Otherwise it's definitely true the object never stops, because it always has the net velocity of Earth's linear and rotational motion.As for the ideal case, it slows down and stops due to the aerodynamic drag of excessive exclamation marks and ellipses.Anyway you and Zeno can't prove itdoesn'tstop (at atomic scale) due to quantum measurement limitations. And Max Planck would like a word with you behind the shed. I don't like the look of that 2x4 (approximately) that he's holding.

author: Jeroen3
author_rank: Super Contributor
timestamp: December 25, 2017, 10:44:23 pm
content: The speed of such object will be a parabola. The derivative of such parabolawill cross the axis.Thefore it will cross 0 speed, but at a infinitesimal small point in time.This is the same thing as clapping you hands. The distance between your hands can halve infinetely, but eventually they do touch.

author: Vtile
author_rank: Super Contributor
timestamp: December 25, 2017, 11:04:52 pm
content: Quote from: TerraHertz on December 25, 2017, 09:21:10 pmWhat about the moon and the satellites on the orbit!!!If you drop a water drop to the water do the distance reach the zero as in the moment they touch there is only one object and it can't have distance between.So is the zero just a logic operator.

author: BrianHG
author_rank: Super Contributor
timestamp: December 26, 2017, 01:05:41 am
content: What if you slice time down to plank time. At this scale, isn't the object and all it's atoms considered stationary at all times?

author: sleemanj
author_rank: Super Contributor
timestamp: December 26, 2017, 08:37:57 am
content: I feel like this is related to Zeno's paradoxHere's James Grime talking about it

author: AndyC_772
author_rank: Super Contributor
timestamp: December 26, 2017, 10:12:25 am
content: Quote from: GlennSprigg on December 25, 2017, 12:04:23 pmAverage speed is given by displacement / time, and in practice, that's how it's measured."Instantaneous" speed is defined by letting the 'time' variable tend towards zero, but already you're into the idealised world of mathematics, where quantities can exist with unlimited precision. The object does achieve the state of being 'at rest', but only at one specific time, is. instantaneously.Bear in mind, there is absolutely no issue at all in mathematics with having something that exists in only a limited number of dimensions. For example, in geometry, a point has no length, a line has no area, and a rectangle has no volume.

author: bd139
author_rank: Super Contributor
timestamp: December 26, 2017, 10:50:58 am
content: Calculus, limits. Go readdy -> 0

author: VK3DRB
author_rank: Super Contributor
timestamp: December 26, 2017, 12:36:42 pm
content: Same reason "now" is infinitesimally short. But the past does not exist, only evidence of what has happened in the past. And neither does the future exist, although we can predict it. So if "now" is infinitesimally short, maybe "now" does not exist. Time does not exist except in relation to something else. So is this all just a dream?

author: GlennSprigg
author_rank: Super Contributor
timestamp: December 27, 2017, 03:03:32 pm
content: Thank you to 'ALL' for your commentsI'm not trying to make 'favorites' but I WAS tickled by the comments from....'DC1MC' and 'TerraHertz' especially......The 'solution' has nothing to do with one's interpretation of 'ZERO', or withperpetual diminishing of 'fractions' like... 1/8, + 1/16, + 1/32, + 1/64 etc etc.......(although the number of 'Exclamation Marks' does dictate the importance of statements...!!!)And of COURSE, I was talking in a theoretical 'world', and so not considering the rotation of the Earth,or the orbit of the Earth around the Sun, or the movements of our Solar System within our Galaxy,or our Galaxies relative movement within the Universe as we know it... which is 'relative' to (.........)...EVERYTHING is 'relative'. Of course, any movement of lesser components down the line are only PARTSof the 'greater' picture. But we need to understand, that even at a LOCAL scale only, that objects cannever 'stop', relative to others. How can they 'stop' for ZERO time !!! In such a 'theoretical' world, theycan slow down in their 'ascent' to maybe 1/100,000,000 millimetres / sec, and LESS, in the last maybe1/100,000,000 of a second, add-infinitum before decending at the same rate of acceleration.It doesn't matter the MASS of the object, or it's 'elasticity'.... it effectively never stops.....

author: CatalinaWOW
author_rank: Super Contributor
timestamp: December 27, 2017, 07:39:04 pm
content: Go a little further with your thinking. You are expressing all of your numbers as fractions, the ratios of real numbers, and therefore rational numbers. But if you go into the maths, there are an infinite number of irrationals between any two rational numbers. So there are an infinity of "stopping" points between your best approximations of a stopping point. None of which we can accurately measure according to the theories of Heisenberg.All of this is based on our current understandings of the world which mostly say that space isn't quantized. But some folks are starting to think that it is.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 27, 2017, 09:43:18 pm
content: Well, probability waves are continuous functions; their solutions however have discrete parameters.Everything in reality (that is, anything that exhibits "thinginess") is finite and quantized.The universe as we know it is in the domain of the rationals.So-called "real numbers" are the least real (physical) set! It's a tragedy of a name; second only to the so-called "imaginary numbers", which have surely confused many a student, being forced to try and imagine something which, by its very name, does not exist...Everything that has ever been computed, and ever can be computed, is a rational number. Rational numbers have a unique concreteness, pragmatism, to me. Even more so, finite rings, if you're much into computers.Yes, math is absolutely reasonable on the irrationals and reals -- but we can only ever truly know such a number by its mathematical properties. How do we define pi? Can we write it out? Of course not, that would be absurd; then it would be a rational, and not have any of its useful properties (at least, not exactly -- which is what counts in math). The rational 1.4142... (to as many digits as you care to write, but never infinitely many, that's impossible) does not have the property that its square equals exactly 2: there is always necessarily some residual.We can only know reals by their properties: pi is the ratio of a circle, among many other equivalent properties. There is an uncountable infinity of reals out there, which we cannot possibly enumerate (well, practically by definition), and most of which would be defined by some unimaginably complex and thoroughly useless combination of mathematical properties. (Indeed, any given real might* exhibit an infinity of equivalent properties with which we could identify it -- pi arises from such simple properties as the ratio of a circle, or as strange as the probability of coprimality of two numbers.)*I suspect it's safe to saywill, but I don't know how you'd even go about beginning to prove that, or prove that it cannot be proven (or prove that, or... erm..).Tim

author: GlennSprigg
author_rank: Super Contributor
timestamp: January 02, 2018, 02:05:33 pm
content: Thanks again to ALL commenters. It was again, interesting readingI realize I may have mislead people a bit, with my 2nd-to-last line...."can you disprove this".... That's not what I really meant/wanted/expected..My 'Subject' was mainly a statement of fact... (I think) that was interesting to 'ponder'.How could an 'object' under the influence of gravity, possibly (and simply) do anything BUTtravel either up or down, as it's 'time' at the TOP was ZERO time ?I'm not even 'trying' to, or need to, mention apparent infinitesimally small 'speeds' priorto the object reversing it's direction, as such values are not applicable regarding the outcome.This discussion is not about 'real' numbers, or 'recurring' decimal places etc etc, ALTHOUGHthat is an interesting discussion in itself !!. Recurring numbers like '1.333333_' can be thoughtof like 'continuously-infinite' fractions/numbers, like... 'Pi' = 3.14159265359_ going on forever.Imagine that again in a PERFECT environment, (with zero thickness pens & dots etc.), I placed aDOT on this theoretical 'page', and asked you to draw another theoretical 'dot' "Pi" inches away !!OR to draw another theoretical 'dot' "Root-2" inches away. (1.4142135623730950488___)You CAN'T define it 'physically' in that way, (remember we are talking perfect pens!!), because Icould always add ANOTHER digit, etc etc, and make the theoretical 'mark' a minuscule fraction ofa distance FURTHER !!... (add infinitum). Hmmm, ok, that sort of makes sense !!HOLD ON !!!.... let's approach this problem from the 'Other End'... (What !)Let's 'Draw' a right-angled triangle... (with the SAME 'magic' perfect graphically theoretical pens!),where the 'right-angle' has length of sides... 1" x 1", so therefore the 'Hypotenuse' = 'Root-2' !!!which = 1.4142135623730950488___ recurring, but there it IS now, between those 2 actualphysical points, within those 2 physical boundary 'points'. No more 'decimal' points neededThis is just to make you think FURTHER sorry....Isn't it fascinating mathematically how not only the the diagonal of a 1x1 right-angled triangle is 'Root-2',but that the internal diagonal of a 1x1x1 CUBE is 'Root-3'......I won't get into 4th dimensional 'Hyper-Cubes'Have a nice day/night where ever you are.Glenn.