What is the newest installment of 'Random Thoughts' on Physics Forums?

[WWGD]

Still weaseling out of dealing with 12 y.o. kid I gave an open problem to. His father told me he was interested in Number Theory, asked me to give him a problem. I asked him to figure out if there are infinitely many primes in the Fibonnaci sequence. It turns out it's an open problem.

Dad told me a while back the kid was racking his brain, depressed he wasn't making headway. Now I try to avoid dad, out of embarrassment.

 

[nuuskur]

Swallow the pride, admit you messed up and give another nut to crack (but make sure it's known to be crackable )

 

[WWGD]

Swallow the pride, admit you messed up and give another nut to crack (but make sure it's known to be crackable )

There's another one that's not open, but seems incredibly hard: there are only 3 perfect squares in Fibonnaci. Might be too hard.

 

[fresh_42]

There's another one that's not open, but seems incredibly hard: there are only 3 perfect squares in Fibonnaci. Might be too hard.

The usual nutjob approach is Collatz. But why not let him prove that there are infinitely many primes and that there is only one prime triple? Playing around with Legendre symbols can also initiate his interest in number theory. Or let him prove that what he probably calls prime is in fact irreducibility. Let him prove that both are equivalent.

 

[ProfuselyQuarky]

too many narcissists

 

[kyphysics]

It's 100°F and is forecast to be 104°F later this afternoon here in my town in Kansas.

Every darn day it seems like the humidity is 70%+ in my city in Virginia.

I wonder if this is related to climate change? . . . I don't mind heat if it's not humid along with it. I hate humidity! It gives your skin an icky feel and causes mold/fungus growth.

 

[gmax137]

I wonder if this is related to climate change?

Humid days and nights are not a new phenomenon in Virginia.

 

[BillTre]

Every darn day it seems like the humidity is 70%+ in my city in Virginia.

I wonder if this is related to climate change? . . . I don't mind heat if it's not humid along with it. I hate humidity! It gives your skin an icky feel and causes mold/fungus growth.

I grew up in Maryland. I though the summers were often more humid there. I remember lots of 95% humidity.
We didn't have air conditions for many years at that time.
I thought the dry summers in Oregon at 105˚F were refreshing in comparison.
Either way its better to condition your body to high temperatures and humidity gradually if possible.

Maybe the air gets drier as the climate heats up?

 

[jack action]

I don't mind heat if it's not humid along with it. I hate humidity!

 

[Borg]

Speaking of humidity, a hydrogen/oxygen reaction produces water so that should put the fire out.

 

[pinball1970]

Supermoon! Get on it!

Optimal was 30th? Still get some nice views

https://www.space.com/biggest-full-moon-of-2023

 

[nuuskur]

2nd derivative negative implies convex ...

I hate school math. Why are concave functions called convex???!

 

[WWGD]

2nd derivative negative implies convex ...

I hate school math. Why are concave functions called convex???!

I've also heard " Concave/Convex Up/Down. Not helpful.
Edit: But Im.not too fond of questions on whether " the function converges "(??)

 

[WWGD]

Strange setup in my friend's place. He uses keys to _ exit_ his apartment.

 

[pinball1970]

Strange setup in my friend's place. He uses keys to _ exit_ his apartment.

To let himself out? That is very bad fire safety

 

[fresh_42]

It prevents you from forgetting the key. And in case of fire, just keep the key within the lock.

 

[pinball1970]

It prevents you from forgetting the key. And in case of fire, just keep the key within the lock.

So to get back in?

 

[fresh_42]

So to get back in?

Yes. That's the plan.

 

[pinball1970]

Yes. That's the plan.

In the event of a fire the first priority is to get yourself and the family out.
Having to use a key for that is wrong. It should be as simple as possible.

 

[gmax137]

It should be as simple as possible.

I agree. But I have often seen exterior doors with deadbolts, and people keeping the deadbolt key inserted on the inside. I think this is acceptable, as long as you don't leave, and lock the deadbolt behind you with other people still inside. Doing that is certainly a dangerous act.

These double-keyed deadbolts are against code, or even illegal is some jurisdictions.

 

[BillTre]

Strange setup in my friend's place. He uses keys to _ exit_ his apartment.

This has be used as an anti-theft strategy.
Thief needs a key to leave through the door with your stuff.

 

[jack action]

Having to use a key for that is wrong. It should be as simple as possible.

How is turning a key - that is already in - more complicated than turning a deadbolt?

 

[berkeman]

How is turning a key - that is already in - more complicated than turning a deadbolt?

Key can break off. Or it could be the wrong key...

 

[WWGD]

Why doesn't someone come up with an app to find parking spots in mega parking lots in shopping centers? Maybe the cost of all the semdors, and relaying data, requiring WiFi?

 

[pinball1970]

How is turning a key - that is already in - more complicated than turning a deadbolt?

Yes sounds simple enough but when the place is hot full of smoke, no vision, you do not want to be grasping for a small key.

 

[fresh_42]

Why doesn't someone come up with an app to find parking spots in mega parking lots in shopping centers? Maybe the cost of all the semdors, and relaying data, requiring WiFi?

Exists. Not an app, but I know at least two parking lots with according traffic lights: green for available slots, and red for occupied sections.

 

[WWGD]

Exists. Not an app, but I know at least two parking lots with according traffic lights: green for available slots, and red for occupied sections.

It would be great if it could be applied city-wide. I'd heard one of the main sources of traffic in L.A was cars going about looking for parking spaces.

Wonder, though, if the law of " If you build it, they will come" applies to parking spaces, as it applies to road construction.

 

[WWGD]

Exists. Not an app, but I know at least two parking lots with according traffic lights: green for available slots, and red for occupied sections.

Wonder if it uses some sensors or just basic counting. If you know you have n spots, you can subtract 1 for every ticket issued by the machine,and add 1 each time someone leaves. Then you get green when $n\geq 1$, and red for $n=0$.

 

[fresh_42]

Wonder if it uses some sensors or just basic counting. If you know you have n spots, you can subtract 1 for every ticket issued by the machine,and add 1 each time someone leaves. Then you get green when $n\geq 1$, and red for $n=0$.

Those I know use simple counting mechanisms, pre-AI, and pre-camera detection. E.g. the parking lot at the airport has a ticket machine with a boom gate for every 60 cars or so per parking section. It counts. You can see free and occupied sections on your way. I wonder how the one at the university hospital works. It has lights on every floor but only a single boom gate at the entrance. But I can't remember having seen cameras.

 

[Borg]

We have something similar in my area. Sensor on the parking spot with an indicator light above. Just look for a green light.

 

[fresh_42]

We have something similar in my area. Sensor on the parking spot with an indicator light above. Just look for a green light.

Ah! Sensors that is!

 

[WWGD]

We have something similar in my area. Sensor on the parking spot with an indicator light above. Just look for a green light.

Thing is, if it's a parking lot giving tickets, if there's only one spot available, it may still allow two cars in, one will end up without a spot.

 

[berkeman]

Why doesn't someone come up with an app to find parking spots in mega parking lots in shopping centers? Maybe the cost of all the semdors, and relaying data, requiring WiFi?

There is indeed an app for that. I don't know if it got past the Beta testing stage, but it has been worked on as a commercial application. I'll see if I can find it...

 

[WWGD]

There is indeed an app for that. I don't know if it got past the Beta testing stage, but it has been worked on as a commercial application. I'll see if I can find it...

Thank you. It brings to mind an old post about the difference between electric and electronic, the latter involving a control system, IIRC/IIUC.

 

[berkeman]

Hmm, after a quick search, I think the app I'm thinking of was just in development at the time. I think my company helped them with some networking issues, and they were using multiple cameras per parking area/garage to be able to recognize open spots. It looks like it was not commercialized. The closest thing I found was this, which I think is more for city street parking...

https://spothero.com/

 

[WWGD]

Kind of weird, noticed how there are several last names around the animal " Wolf". I remember : Volpe, Lupo, Wolf itself, Wulf, Wolff, Lobo. Likely more in languages I don't speak.

 

[LCSphysicist]

I joined this forum years ago at the beginning of my undergraduate program. Now, I am almost graduated. Sometimes, I think about where the other students and users who joined with me are (mainly, one genius boy that i can't renember the user, but people will know who i am talking about).

 

[pinball1970]

I joined this forum years ago at the beginning of my undergraduate program. Now, I am almost graduated. Sometimes, I think about where the other students and users who joined with me are (mainly, one genius boy that i can't renember the user, but people will know who i am talking about).

Nice you have been here the whole time.

 

[WWGD]

I joined this forum years ago at the beginning of my undergraduate program. Now, I am almost graduated. Sometimes, I think about where the other students and users who joined with me are (mainly, one genius boy that i can't renember the user, but people will know who i am talking about).

You may be referring to @WannabeNewton
Or similar name. I miss @zoobyshoe. I checked his avatar and he last posted in 2017.

 

[LCSphysicist]

You may be referring to @WannabeNewton
Or similar name. I miss @zoobyshoe. I checked his avatar and he last posted in 2017.

Actually, I have remembered the username. Ethotepi? Something like that. The users you mentioned aren't near my age, but i do remember the first one.

 

[WWGD]

Actually, I have remembered the username. Ethotepi? Something like that. The users you mentioned aren't near my age, but i do remember the first one.

The ones I mentioned join in the 2000-2010 era, and were active through around 2018. Notice PF was started by Greg B in 2001.

 

[WWGD]

My friend complains his wife, who's around a foot shorter than him and some 100 lbs lighter, expects him to eat the same amount of food as her. I agree with him, though I can't think of the multiple by which his amount should be larger, but it certainly should be larger.

 

[Borg]

Actually, I have remembered the username. Ethotepi? Something like that. The users you mentioned aren't near my age, but i do remember the first one.

Probably Etothepi (E to the pi)?

 

[WWGD]

I think it's @etotheipi

 

[jack action]

Actually, I have remembered the username. Ethotepi? Something like that. The users you mentioned aren't near my age, but i do remember the first one.

It was @etotheipi, it is now @ergospherical and still active as of last month.

 

[gmax137]

this reminds me, I have been wondering about @anorlunda , have not seen any posts from him in a while now. Checking, I see his last post was in February. Hope he's OK!

 

[WWGD]

How about @zoobyshoe or @WannabeNewton?
They last posted in 2017, 2018 respectively. Any one know what happened to them?

 

[berkeman]

this reminds me, I have been wondering about @anorlunda , have not seen any posts from him in a while now. Checking, I see his last post was in February. Hope he's OK!

He replied to my e-mail and says he is doing fine and thanks for the concern. He has found a new passion at some specialized websites, hence the reduced participation here at PF.

 

[Frabjous]

found a new passion at some specialized websites

Interesting euphemism

 

[berkeman]

Interesting euphemism

No, no, no. Not *that* kind of website... Sheesh!