Science addicts here?....

[OldFartTom]

Maybe this is engineering not science, but we have a lot of engineers here. Weiss??? Others?? You reading this?

If I drop and object, or let it will down a slope I exchange potential energy from gravity
height * mass * acceleration due to gravity
for kinetic energy
mass * velocity squared

hmg = mv^2
Or
hg=v^2
Or
Root hg = v

Easy, so velocity is purely related to height (assuming constant gravity everywhere and treating as a constant not a variable)

So why the **** is this? I can't get my head round it, this is voodoo. I realise it's an illusion, I still can't get my head round it

[Wayne Evans]

Maybe this is engineering not science, but we have a lot of engineers here. Weiss??? Others?? You reading this?

Hey OFT....it's all good.

Hmm.....

In my ignorance, prior to watching it, I quickly dismissed thinking any acceleration related to the dips would be determining.
It would be easy to guess the incline plane would win the race but figured that would be too hasty a presumption.
Very interesting experiment to witness.

Your equations made me a bit dizzy....I think I'll have a high ball.

Thanks for sharing that amigo.....(on spread)

Have a great day....

[7Seconds]

So why the **** is this? I can't get my head round it, this is voodoo. I realise it's an illusion, I still can't get my head round it

I am not smart enough to answer your question but this seems like a decent observation of why roller coasters are much more fun than slides.

ETA:

And having a drink as well. Cheers Wayne!

[Wayne Evans]

I am not smart enough to answer your question but this seems like a decent observation of why roller coasters are much more fun than slides.
And having a drink as well. Cheers Wayne!

Ha...."cheers" back to you SEVEN.
I love all of this we discuss here but the more I discover the less I think I know....go figure?

I'm not smart enough either.
On that note....belly up weed hopper!...I'm buyin'.

Carry on....(on spread)

[BlackJack619]

What's the largest flattest piece of land there can be on a round planet?

[Wayne Evans]

What's the largest flattest piece of land there can be on a round planet?

I don't think any round object has a truly flat surface....regardless of our understanding of what the smallest particle is.

But, that's just me.

(Hmmm....where's my drink? SEVEN.....you seen my glass?)

[BlackJack619]

I don't think any round object has a truly flat surface....regardless of our understanding of what the smallest particle is.

But, that's just me.

(Hmmm....where's my drink? SEVEN.....you seen my glass?)

What if instead we used the word and understanding of level.

[OldFartTom]

Hahahaaaa it all clicked into place I looked again after a nights sleep, knowing it's an illusion - the video is even gravity named illusion - and see it straight away

Spoiler!

On the steep (concave) bits it goes faster than the slope (incline plane), on the flatter bits (convex) it goes slower than the slope.

Seen from directly above with a much longer track I think you'd see both moving at same average speed but the ball on the bumpy track pulling into the lead then falling behind then pulling into the lead then falling behind.

The track ends where it is ahead. If the track was two inches longer it'd look like the slope (incline plane) was the winner

Well I think that's how it works, if I knew the correct name for the illusion I could Google a definitive answer.

It kept me thinking a while before I spotted it. Hope you guys enjoyed it as much as I did

[OldFartTom]

What's the largest flattest piece of land there can be on a round planet?

What do you mean by flat? If you mean in terms of things like a pool ball not rolling about, then an ocean covering a spherical planet is flat and if I levelled it with lots wooden pegs and a 6 foot spirit level, pouring leveling compound on the floor etc it's level

If I use a laser level, dumpy level (theodolite spirit level), etc then it's a different meaning of flat but will curve a calculable amount only significant on planetary scale due to light bent by gravity of the planet

Or do you mean mathematically flat, some kind of mathematical plane?

I'm happy with a 6" level and wooden pegs answer and I'll reply "as big as we have time to do the job"

[steffo99]

Cool little animal came to life after 24000 yrs in the ice, and reproduced.
https://www.abc.net.au/news/science/...rost/100191788

[steffo99]

OldFartTom, just noticed your text:"Bodyweight 73g (03/June/2021)"...now that is taking dieting to the extreme!

[Wayne Evans]

Cool little animal came to life after 24000 yrs in the ice, and reproduced.
https://www.abc.net.au/news/science/...rost/100191788

Howdy Steffo....

Good find....very interesting to say the least. (on spread)

Have a great day everyone....

(104 degrees in the hearland today....I'll be in my basement studio where it's far more comfortable)

[PhDPepper1111]

Howdy Steffo....

Good find....very interesting to say the least. (on spread)

Have a great day everyone....

(104 degrees in the hearland today....I'll be in my basement studio where it's far more comfortable)

Oof stay cool! Had a candidate tell me that in Phoenix area it's been over 110 every day this week! Now that's wierd science!

[OldFartTom]

OldFartTom, just noticed your text:"Bodyweight 73g (03/June/2021)"...now that is taking dieting to the extreme!

Ha has. Sorry only just noticed this post and sure enough I still have g. oops!
Thanks for telling me, better bulk up 1000 times, quick!

[steffo99]

Potato-human hybrids. What's next?


https://wonderfulengineering.com/the...e-proportions/

[steffo99]

Just linking this new talk between 2 guys I enjoy listening to, going back and forth on the nature of reality and more. I don't find many new docus on stuff like this anymore, but there's always alot available in the forms of panel shows and lectures etc.

[Wayne Evans]

Hey Steffo....

I've seen Max many times over the years in several doc episodes.
I love listened to this stuff that ties my pea brain into knots.
I don't recall the other guy so much.

I took algebra (1) once when in college back during the Holocene Epoch.....then the person sitting next to me woke me up so I could go drop the class.

A good eve to all.....

[PhDPepper1111]

Hey Steffo....

I've seen Max many times over the years in several doc episodes.
I love listened to this stuff that ties my pea brain into knots.
I don't recall the other guy so much.

I took algebra (1) once when in college back during the Holocene Epoch.....then the person sitting next to me woke me up so I could go drop the class.

A good eve to all.....

Haha well done with the post...

As to the near-speculative fiction aspect of these docs... still fascinating to consider!!

[Wayne Evans]

Haha well done with the post... As to the near-speculative fiction aspect of these docs... still fascinating to consider!!

Howdy doody....

In this context:
In spite of much of this being 'speculative' (which I agree with) it's these very [/I]speculative banter of thinking outside the box[I] by these deeper thinkers (for lack of better terms) that will eventually lead to great epiphanies of understanding the world/cosmos that surrounds us.
(whew....that was a mouth full....I need a drink)

Oh...did I mention I suck at math.
(algebra equation : 2a + 4 = 10....I actually know to calculate the answer to this one!)

Carry on....

[steffo99]

Hey Steffo....
I don't recall the other guy so much.

Brian Greene had his own docu series on quantum physics and string theory I think it was...should be on youtube somewhere but it's probabaly 10-15 yrs old now. I haven't done math since school either and don't have a science degree, just a lifelong curiousity for this stuff. Selected science as as a sort of major in high school, but since it was all math all day long it wasn't quite what I hoped for and switched over to business so at least I was in the same room as all the hot chicks.

[steffo99]

As to the near-speculative fiction aspect of these docs... still fascinating to consider!!

To think we are still finding out about the nature of reality is mind-blowing in a way. And I suppose everything we now know was fiction at some point.

[Wayne Evans]

it was all math all day long it wasn't quite what I hoped for and switched over to business so at least I was in the same room as all the hot chicks.

Ha...

Well...I'm impressed because I think that makes you a 'deep thinker' too.

On spread with recent contributors.

Que tenga un buen fin dessmana todos.

Carry on....

[steffo99]

Still have an illustrated space adventure book I wrote at age 6 or 7 or so. Not exactly Carl Sagan level but glad I found that a while back going through old boxes.

[steffo99]

[Wayne Evans]

Howdy steffo....

Good stuff.
I've watched a few others by him.

I anxiously await the JW launch.
https://www.nasa.gov/press-release/n...ecember-launch

Carry on....

[numberguy12]

way too late responding, ha, but neat little video there.

I agree that velocity is related to height, in that the kinetic energy [1/2mv^2] increase is the change in potential energy ignoring friction*, but this does not give the whole story for the time it takes the ball to go from A at the top to B at the bottom. The time will depend on the length of the path, and also how fast the ball is going at different points, which varies by the type of path. The avg velocity will also be different depending on the path.

This can be stated succinctly as T = ∫dt or T = ∫dS/v[x,y], or in other words, the total travel time is the sum of all the tiny bits of time for the little stretches of path with length dS, and in which the velocity of the ball is v[x,y] at point [x,y], noting this velocity is essentially constant over a very small chunk of track....this is just the old time = distance/rate. Actually we could write just v[y] since velocity is only dependent on height by the potential/kinetic energy relationship.

The point here is to find the time it takes a ball to go from starting at rest at A to B with just gravity acting on it. [not considering friction for any of this post]


•A [0,h] .....................................•[x,h]




•[0,0]........................................•B[x,0]


You could make it an inclined planed from A to B, and the acceleration of the ball along this straight line will be gsinθ the whole time**, where θ is the angle of elevation of the inclined plane. Instead, consider if you have a track that is essentially the ball being dropped from A to [0,0] in free fall, then continuing to B along the bottom line. In this case, the ball is going faster for the trip than the straight inclined plane route, but it is a longer path. [it turns out this would be faster than the straight line....but still not the fastest path]. You could also make the trip take as long as you want: make the path a very, very slight descent from A to just below the upper right point at [x,h] (say, at an angle of descent of .00000000001degrees), and then the ball drops in free fall from that point to B. The ball would be moving extremely slowly as it goes from A to [x,h], and the total travel time could be made to exceed any number.

What is the fastest path from A to B? Many students in physics 101 guess it is the straight line A to B because that's the shortest distance. It is not. It turns out to be the mathematical curve called the cycloid, which is traced by a point on the circumference of a constantly rolling circle. This is called the brachistochrone problem, and has a rich history:

https://en.wikipedia.org/wiki/Brachistochrone_curve

"brachisto"- shortest, "chrone"- time, in Greek. Looking at the illustration in that wiki, the ball on the cycloid path, the red path, beats the straight line from A to B. It's the path of least time, and this can be proven by minimizing that integral above using methods from the calculus of variations.
Around the late 17th century it was posed as a challenge to the leading mathematicians who were just discovering the mathematics needed to prove it...while some such as Jacob Bernoulli did solve it in years' time, it is said Newton got the problem and solved it by the next morning...an example of the genius of Newton.

In the video, the path taken by the ball on the left is longer than the one on the right. However, it achieves high velocity right off the bat with the steepness, to more than counteract this, such that the overall time of travel is less. It would not matter if the track is extended in the same fashion a few inches, it will still win. You will notice the ball on the left is clearly ahead the whole trip. It is just a faster path of travel under gravity [assuming the friction is minimal].

*: funny foxtrot comic illustrating this: https://www.gocomics.com/foxtrot/2019/09/29

**: there are nuances here, such as the ball is rotating and is not just an object sliding down the plane due to gravity (thus some of potential energy is converted to rotational energy as well), but this is not important for the overall point.

[OldFartTom]

Thanks numberguy12... busy reading and digesting

[Wayne Evans]

Howdy....

Well....the time has arrived.

"NASA announced today that the launch of JWST is now scheduled for Dec. 24, 2021, at 7:20 a.m. EST. JWST currently sits atop an ESA Ariane 5 rocket, a very reliable heavy lift workhorse. All checks have been completed and JWST is all set for launch … the countdown clock is running. It is not an exaggeration to say that all involved in the building of JWST and the worldwide astronomical community that is so eager to use JWST, is probably feeling a mix of tension, anxiety and exhilaration as the moment to lift off approaches."

https://www.youtube.com/results?sear...pe+launch+date
https://www.google.com/search?client...grange+point+2

Twenty five years or so from conception to this moment.
I can certainly imagine the anxiety within the whole science community and I share it.
18 mirrors amounting to 6X the size of Hubble and 100X more powerful.

IIRC.....about a month to arrive at L2 orbiting position and a couple weeks to get all systems deployed.
I'm really looking forward to it's success and thanks to Canada, UK and US for making this event a reality.
It's success should offer some stunning new realizations.....if all goes well, that is.

If the date holds it will be a great Christmas eve.

Carry on....have a great weekend.

[OldFartTom]

Will be extremely interesting. Hubble was a heavily customised version of a (sort of) off-the-shelf satellite albeit a specialist type, ermm.. let's call them "earth facing telescope satellites" that they pointed it towards space instead. But this JWST is built from scratch as a space telescope and way way more powerful. Will be very interested to see the results!

[Wayne Evans]

Will be extremely interesting. Hubble was a heavily customized version of a (sort of) off-the-shelf satellite albeit a specialist type, ermm.. let's call them "earth facing telescope satellites" that they pointed it towards space instead. But this JWST is built from scratch as a space telescope and way way more powerful. Will be very interested to see the results!

Absolutely!

Hubble was great in it's own right but only measured visible light and JW measures the IR and medium IR.

If it's a success that good enough of a Christmas for this old bird.

Back to it....