This is an old revision of this page, as edited by Sarcelles (talk | contribs) at 16:02, 24 October 2024 (→Founding members of CARE International, 27 November 1945: new section). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

• Computing
• Entertainment
• Humanities
• Language
• Mathematics
• Science
• Miscellaneous
• Archives

• WP:RD/M

Main page: Help searching Misplaced Pages

How can I get my question answered?

• Select the section of the desk that best fits the general topic of your question (see the navigation column to the right).
• Post your question to only one section, providing a short header that gives the topic of your question.
• Type '~~~~' (that is, four tilde characters) at the end – this signs and dates your contribution so we know who wrote what and when.
• Don't post personal contact information – it will be removed. Any answers will be provided here.
• Please be as specific as possible, and include all relevant context – the usefulness of answers may depend on the context.
• Note:
  • We don't answer (and may remove) questions that require medical diagnosis or legal advice.
  • We don't answer requests for opinions, predictions or debate.
  • We don't do your homework for you, though we'll help you past the stuck point.
  • We don't conduct original research or provide a free source of ideas, but we'll help you find information you need.

How do I answer a question?

Main page: Misplaced Pages:Reference desk/Guidelines

• The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.

• Teahouse
• Help desk
• Village pump
• Help manual

October 10

Kathy Andrade

Was the Kathy Andrade who was a friend of the victim Murder of Reyna Marroquín the same woman as Kathy Andrade, the Salvadoran-American union activist? I can't find any reliable sources. TSventon (talk) 20:33, 10 October 2024 (UTC)

Andrade was on Forensic Files in 2000, described as a union activist and a friend of Marroquin. 68.187.174.155 (talk) 01:16, 11 October 2024 (UTC)

This is the Forensic Files episode with Kathy Andrade in it. She appears about 15 minutes into it. 68.187.174.155 (talk) 16:48, 11 October 2024 (UTC)

Thank you, it looks like the same woman, does the programme describe her as a union activist? TSventon (talk) 17:15, 11 October 2024 (UTC)

I notice that "The uploader has not made this video available in country ": are you in the same position? {The poster formerly known nas 87.81.230.195} 94.6.86.81 (talk) 19:59, 11 October 2024 (UTC)

There is also a copy on Dailymotion. TSventon (talk) 20:32, 11 October 2024 (UTC)

The Forensic Files episode "A Voice from Beyond" only identifies Kathy Andrade as a friend of Marroquín, but all details fit. The episode reveals that Marroquin took lessons at the High School of Fashion Industries and attended Andrade's English class. Andrade is shown, talking about her frjend Angélica Marroquín, saying, "her dream was to become an American citizen". Our article on Kathy Andrade states that she was Education Director for Local 23-25 of the International Ladies Garment Workers Union and organized various educational programs for union members, supporting their paths to citizenship. Also, we see a page of Marroquín's address book with Andrade's address, "311 W 24 ST", which is in the Penn South housing development where our article on Andrade states that she lived. While this is very strong but circumstantial evidence, the person seen speaking in this episode is clearly the same as shown in a photograph in Andrade's obit in The New York Yimes, captioned, "Kathy Andrade at a rally in Manhattan in 2006 on behalf of immigrants' rights". Kathy Andrade's biography at IMDb – not a "reliable source" – also makes the identification: "Was a leading union activist for garment workers in New York City for over 50 years. Assisting many Latin American workers, she became friends with a fellow Salvadoran worker by the name of Reyna Marroquin."  --Lambiam 07:45, 12 October 2024 (UTC)

@Lambiam: thank you for the detailed reply. I found "Kathy Andrade" on a list of orphaned articles and added a wikilink to the existing mention at "Murder of Reyna Marroquín" after a brief investigation. I had checked the IMDB, but know that is user generated. I think your answer is sufficient to convince me that the link was correct. It would be nice to have an online news source which joins the dots but not vital. I calculated that the 30 days after I added the link got 27 times as many views as the 30 days before, which shows how popular murder is on the internet. TSventon (talk) 16:52, 12 October 2024 (UTC)

October 13

Slowing down time

What are some ways I can slow down time (or relax) without using drugs or marijuana (since I hope to God I don't try any)? TWOrantula (enter the web) 02:45, 13 October 2024 (UTC)

Unfortunately I don't have a copy near me right now to check the details, but memory tells me that a character in Catch-22 by Joseph Heller chose to deliberately watch and involve himself in boring activities so that it would feel like he was living longer in a time and place where dying was highly likely. I welcome clarification from those with better memories or an actual copy of the book. HiLo48 (talk) 03:08, 13 October 2024 (UTC)

If Tom Lehrer's inference is to be believed, you could try listening to Das Lied von der Erde on repeat. ←Baseball Bugs carrots→ 03:28, 13 October 2024 (UTC)

Meditation. Some recommend mindfulness, which can be seen as a specific meditation technique.  --Lambiam 08:14, 13 October 2024 (UTC)

For various reasons, I have lately been sleeping in two bouts of about 4 hours in 24, rather than one of about 8. A side effect I have noticed is that time seems to pass more slowly, perhaps because almost every time I wake up it's still the same day. This does of course require one not to need to interact with others on a more normal schedule very much. {The poster formerly known as 87.81.230.195} 94.6.86.81 (talk) 09:32, 13 October 2024 (UTC)

I tend to find that waiting at a bus stop achieves this very well. Shantavira| 18:57, 13 October 2024 (UTC)

Depending on your phobic predipositions you may take a few moments following the second hand of the stopwatch. Alternatively or not, do it while listening to some recorded works after Franz Tunder. Without a stopwatch it will require enough free space for pacing back and forth for a few steps. --Askedonty (talk) 19:00, 13 October 2024 (UTC)

There's always the proverbial "watching grass grow" or "watching paint dry". Or, you could get one of your namesakes to keep as a pet in a terrarium, and watch it all day, because they just sit there doing nothing most of the time. ←Baseball Bugs carrots→ 22:52, 14 October 2024 (UTC)

Occasionally wildly dancing a tarantella when nobody's watching. Clarityfiend (talk) 00:33, 15 October 2024 (UTC)

In the 1950s, Clint Eastwood thwarted that frenetic dance in Napalm Springs. ←Baseball Bugs carrots→ 13:28, 16 October 2024 (UTC)

October 14

Questions on environmental sustainability and whitewashing definition

Electric toothbrush#Environmental concerns

In this article what do they mean by "A plastic manual replaceable head toothbrush was probably the best, according to the study."

2020s in fashion#Barbiecore, McBling, and gyaru

And in this article what do they mean by "whitewashing" in this context? 58.104.108.223 (talk) 05:23, 14 October 2024 (UTC)

That term does not appear in the cited sources, but might have to do with white Barbie-doll types being the fashion standard. ←Baseball Bugs carrots→ 07:44, 14 October 2024 (UTC)

As to the first question, they meant a toothbrush that was fashioned from plastic (and not from bamboo), with the brushing action effected manually, by the user by moving their hand (and not with an electric motor), and with a head that was not fixed, but could be replaced on the toothbrush's handle when it was worn out, instead of the user discarding the whole assembly, not only the head but also the handle.  --Lambiam 09:54, 14 October 2024 (UTC)

I found the following in source 354 (https://www.teenvogue.com/story/the-y2k-style-trend-isnt-fatphobic-our-attitudes-about-it-are): Ads and runways showcasing the trends also sent another message. In an article called The Fatphobic & Racist Origins of Y2K Fashion Trends, Aishwarya Jagani cites Sabrina Strings in Fearing the Black Body: The Racial Origins of Fat Phobia, in which she explains how “Y2K fashion’s emphasis on thinness…erased the creative contributions of the Black community, attributing styles popularized by people of color to the white celebrities of the time.” The popular image of the day was of thin, white women, further limiting what society saw as beautiful.

I believe this is what is being referred to as "whitewashing". --User:Khajidha (talk) (contributions) 11:16, 14 October 2024 (UTC)

I don't see the "thorough" criticism (or any criticism) of McBling, though.  --Lambiam 16:08, 14 October 2024 (UTC)

October 16

Container islands in New York East River

I don't know what words to use to get a good search for this topic. If you look at satellite images of the East River in New York, you will see multiple rectangular "islands" that look like shipping containers stacked up. The images are very low quality, so it is possible the appearance is just artifacts of image compression. Are there actually stacks of shipping containers or something of similar appearance in the East River? If so, what are they? I originally dismissed it as the satellite picking up container ships moving along the river, but many of them are in the exact same place across more than one satellite image. So, they must be stationary. An example of one is off shore from the Rose M Singer Center on Riker's Island. On Google, it looks like a stack of containers. On Bing, it lookse like a rectangular building. Neither one labels it. Another one is halfway between Soundview pier and Ferry Point Park pier. 68.187.174.155 (talk) 14:28, 16 October 2024 (UTC)

A mystery! To me on the satellite photos they look like they could be barges either filled with loose material or covered in a light coloured tarp. To get a different angle, I looked for some near Google Street View coverage. There are a couple of mystery objects just east of the Bronx end of the Whitestone Bridge, and Street View coverage looking out over the East River at the south end of Robinson Avenue in Throg's Neck. Looking south on Street View, you can see what look very much like barges around the same location as the objects in the satellite photos.

As for what they're doing... Is the East River dredged regularly? That might explain them being there frequently/with long linger times, but also moving around - as a barge is filled up it moves off to deposit the fill elsewhere. 91.194.221.225 (talk) 14:54, 16 October 2024 (UTC)

Lokking on Bing Maps, the object off Rikers Island looks like a lighter with six or seven piles of material (maybe sand or gravel) onboard. There is a much smaller circular object close by, probably a bouy. Alansplodge (talk) 16:36, 16 October 2024 (UTC)

Maybe those are anchor spots for barges when not in use. That would explain why they are in the same location, but appearing rather different, from two obviously different satellite passes. I didn't try a street view of the first one because I assumed there is no street view on Riker's Island. It turns out there is a "street view" from a sailboat, but the sail blocks view of the object. However, following that sailboat's path, I did see that the object between the piers is clearly a flat, red-sided barge full of containers. It is too flat to be a container ship (assuming that refers to those massive ships with hundreds of containers). Assuming these examples (and the many others I found) are anchor spots, I can start googling for official anchor spots along the East River. 68.187.174.155 (talk) 18:51, 16 October 2024 (UTC)

A guide once pointed me at such buoys during a school excursion to the port of Rotterdam, floating in the Waalhaven. You can view them there too. They're meant to tie vessels to, to moor away from the dockside. This can be to store empty barges, to use barges as floating storage or to transship directly from one ship to another, using floating or on-board loading facilities. Traditionally, cereals are transshipped that way. A giant floating vacuum cleaner comes alongside the ocean going ship, sucks up the cereals and dumps them in a river barge for transport deeper inland. If you scroll a bit in time on Google, you can find some ships transshipping bulk goods in the Waalhaven.

There's a lot of sand extraction along the Maas and Waal rivers, where I used to live. It's collected by dredging and sometimes dumped directly into a ship. It looks quite different from the piles you see in the barges near New York. The dredged material is pumped into the cargo hold as a very wet slurry. The sand sinks to the bottom of the hold; the water flows out. There're no visible piles. The material in the pictures was dry when loaded and must have been loaded by chute or conveyor belt.

If the material in the hold isn't sensitive to weather, the cover of river barges is often left off. This saves time. The cover consists of segments of sheet metal, optionally painted, that can be moved using a small portal crane. Sometimes the segments have wheels running on tracks, so that one segment of the cover can be rolled over another. PiusImpavidus (talk) 18:54, 16 October 2024 (UTC)

With all the information here, I've found plenty of documentation for anchorage regulations throughout the rivers around New York and the locations where there seem to be barges are in fact official anchorages. They are not digital encoding artifacts in the satellite images. 68.187.174.155 (talk) 18:59, 16 October 2024 (UTC)

New York (as well as other cities) used to accumulate its garbage on barges, prior to its being disposed of in landfill sites or elsewhere/otherwise; finding places to do so became problematical – see for example Mobro 4000. Such procedures may still be in operation to some extent, and such barges can remain moored in place for long periods: I have seen similar barges remain for weeks at a time in Southampton harbour, beside which I used to work (there is a large refuse incineration plant on the Western shore of the harbour). Storing refuse thusly is relatively cheap, and keeps it from causing onshore problems with vermin, smells, fires, etc. {The poster formerly known as 87.81.230.195} 94.6.86.81 (talk) 23:25, 16 October 2024 (UTC)

Road signs in China

Do road signs in China also inculde place names in pinyin? At least some signs in urban areas do that, but how widespread is this? Do they use toneless pinyin as English names? --40bus (talk) 15:43, 16 October 2024 (UTC)

It depends entirely on the area. Hong Kong has a lot of English signs due to the history of English rule and many English speakers still residing there. Beijing is an international city, as with any capital city. It has not only English, but other languages depending on the area of the city and who will likely be using the signs. Shainghai is a big business city with a lot of foreign residents and tourists. They adopted English and Pinyin as the alternative language for most signs. There is always an argument to remove English and Pinyin from the signs, but it doesn't progress much. If you travel away from locations with a lot of foreign residents and tourists, the chance of finding a sign in English or Pinyin drops. If you get near country borders, you will find signs with the other country's language along with Chinese for the same reason that English is found on signs where many people are expected to know English to some degree but not Chinese. 64.53.18.252 (talk) 21:20, 16 October 2024 (UTC)

In the top 20-50 cities destination signs are in characters and pinyin. DOR (ex-HK) (talk) 23:44, 16 October 2024 (UTC)

While falling asleep, I thought that this is closely related to another topic. Many languages use similar words, so it is not necessary to translate. For example, police in English is police in French, Polizia in Italian, policía in Spanish, politi in Norweegian, poliţie in Romanian, pûlis in Kurdish... etc... Because the word is so similar across languages, there is no need to translate it. When it is different, as in Russian, you will often see it translated from полиция to politsiya. But, in Chinese, there is no way that a person who does not read Chinese to mentally shuffle the phonetics of 警察 to jǐngchá to Police. There is a need to translate words to a language that most visitors will recognize enough to understand. As English has borrowed so heavily from everyone else, it is a good choice for a catch-all/sounds-alike language. My personal experience is that most countries do not translate much. Instead, they use signage that doesn't require translation. I was easily able to get by in Spain, Italy, Turkey, India, Brazil, and Panama without having any knowledge of the local language. In Norway, I was amazed that their written language is so much like English that I thought they were translating. They simply pronounce the words different. 68.187.174.155 (talk) 14:54, 18 October 2024 (UTC)

October 17

Some vehicle-related questions

In recent months, I have become interested in personal watercraft and other recreational vehicles. I’ve been doing a lot of reading about these things and I’ve found one or two areas which confuse me. I am aiming to get these matters clarified in order to ensure I have the right information necessary to make an informed decision about acquiring for myself something of this sort. I would appreciate it if you could take a look at look at these things for me.

The first point of confusion for me would appear to be pricing. My understanding of this is rather poor, and I’m making a lot of assumptions based on the prices of cars and motorcycles. What I am confused by is how high the price tags are for things such as 2-seater aeroplanes and rigid inflatable boats. The planes seem on the surface to be not that much heavier or more powerful than an average motor car, yet they have six digit prices. The boats seem to be as expensive as a family car despite being considerably lighter and less mechanically complex. Why are the prices so high, and why isn’t anyone offering these types of vehicle at a lower price? What is it about the planes that stops them from being made as cheap as a 1.5 tonne automobile? And, what is it about the RIBs that makes them have 5 digit prices despite being made of rubber and not metal?

The other thing that I’m not quite sure about is the fact that battery electric technology still hasn’t completely taken over yet as far as recreational vehicles are concerned. In particular, even in light of climate change and respiratory concerns, gasoline powered go-karts and boats are still quite common. While I understand that price and battery size are important issues at the moment, I still would have thought that the technology would be a no-brainer for such small vehicles. Why would anyone risk damaging their lungs by using a petrol go-kart on an indoor tracks? Wouldn’t that be as bad as smoking? And, why haven’t batteries completely replaced fossil fuels for vehicles, such as small boats, jet skis, motorcycles, quad bikes, and snowmobiles? Why do people still support climate-destroying engines when battery-electric alternatives are possible with today’s technology? This is especially strange, when it would be easy to do battery swaps to deal with charging times.

I hope I can have some light shed on these mysteries. Then, I can make a more informed choice and be less confused. Thank you. Pablothepenguin (talk) 21:12, 17 October 2024 (UTC)

Price: There are several major factors in the cost of producing a factory-made vehicle (or any other manufactured item).

One is the cost of designing it, including the (often considerable) costs of demonstrating to the relevant regulating bodies that it will be (and continues to be) safe. This is a fixed cost, the same if you then go on to make one hundred or one million of the vehicle.

A second is the cost of making the factory that will make the vehicle. This is also largely fixed.

A third is the labour costs of paying the people who make the vehicle, manage the factory, etc. This generally increases with time (because wages usually increase), and obviously has a lower bound.

A fourth is the cost of the materials and components. This is variable, because the more you make the bigger discount you will be able to negotiate on bulk purchase, but it has a lower bound.

(There are other costs, such as marketing, after-sales service and spares manufacture, etc., but let's ignore those for the moment.)

The first two costs have to be recovered by spreading them over the price of all the vehicles sold, over and above the third and fourth which are inherent in producing each vehicle. This means that the more vehicles that are sold, the less that each individual vehicle's price will have to cover those upfront costs (which may have been paid for by investment or borrowing, which generate dividend or interest costs that also have to be covered).

'Average motor cars' are typically made (often in already-established factories that can easily switch to new designs) and sold in hundreds of thousands per model, so the first two costs are spread very thinly.

Vehicles such as recreational aeroplanes and boats are sold in much smaller numbers, so the upfront costs to be recovered are much higher per individual vehicle.

This is a very crude and non-comprehensive outline, based on my experience of working in both retail and manufacturing environments. No doubt an expert can give a far better one. I have some thoughts on battery power, but I'll leave that for others. {The poster formerly known as 87.81.230.195} 94.6.86.81 (talk) 03:45, 18 October 2024 (UTC)

Today's popular consumer cars are manufactured in assembly lines in a continuous process using highly automated processes. At the rate in which they are produced, the automation results in considerable savings on the production costs. The rate of production of 2-seater aeroplanes or rigid inflatable boats of any brand is far lower, not justifying a comparable investment in automation.  --Lambiam 05:27, 18 October 2024 (UTC)

Another factor is that aircraft manufacture and component parts are subject to a far stricter regime of quality control. Alansplodge (talk) 09:36, 18 October 2024 (UTC)

Does anyone know why 60 year old Cessna aeroplanes are still super expensive. Surely oldness = cheapness, right? Pablothepenguin (talk) 11:36, 18 October 2024 (UTC)

Also, can anyone explain why a rubber boat comes in at a five figure price? Why can’t such things be cheaper than metal vehicles? Pablothepenguin (talk) 11:39, 18 October 2024 (UTC)

I note that a Rigid inflatable boat is not inflatable except for the sides. I too am somewhat puzzled by the steep price. Leaving material costs out of it, there are some mysterious market forces at work. Old leisure boats, typically small cabin cruisers, are frequently abandoned and left to rot, yet those offered for resale are typically in relatively good condition and still offered at relatively high prices. I suppose the main cause of the high price is that people looking to buy boats have money, and want good quality. On the positive side, this means there is no RIB market for lemons.  Card Zero  (talk) 14:27, 18 October 2024 (UTC)

Any/one know anything about the aforementioned 60-year-old planes or RIBs? Pablothepenguin (talk) 19:51, 18 October 2024 (UTC)

Size of production run has already been covered.

The engine size may appear to be similar for cars compared to boats or aeroplanes, but there's one difference. Car engines only run at maximum power for a few seconds a time when accelerating or a few minutes when climbing a steep hill at high speed – but most steep roads are to sinuous for high speeds. So car engines are only designed to run at peak power for a short time. Engines of boats and aeroplanes run close to peak power almost all the time. Worse, they have to be more reliable. If a car engine breaks down, you simply coast to a stop; if the same happens in an aeroplane, you have to find a suitable landing spot very nearby or you crash. The engines of racing cars do run at full power all the time; maybe you've noticed how often one breaks down during a race.

As for making them battery-electric, some are. Slow recreational boats have been electric for decades. The sporty ones however need such a high power-to-mass ratio that battery power would only last a very short time, maybe half an hour. For an aeroplane, half an hour is about the limit now and it won't be sporty at all. Go-karts can certainly be made battery-electric or on overhead power (think bumper cars), but some users seem to like the noise and smell. Battery swapping could work, but battery designs must then be standardised and demand high enough, or charged batteries will be waiting for ages before a user comes to pick them up. PiusImpavidus (talk) 09:48, 18 October 2024 (UTC)

And yet an electric car can last for over 200 miles. Explain that? Pablothepenguin (talk) 11:43, 18 October 2024 (UTC)

Bearing in mind that said cars are much heavier, maybe 2 tonnes, than any boat or go-kart, therefore they take a lot more energy to move and still too 200 miles on a full charge. Explain that? Pablothepenguin (talk) 11:47, 18 October 2024 (UTC)

First, an electric car may carry several hundred kilogrammes of batteries. It's a significant fraction of the loaded vehicle weight and you can't increase that fraction much on other vehicles. And for vehicles lighter compared to the person using it, you'll get less battery compared to loaded weight, therefore less battery compared to energy use (weight is often a decent proxy for energy use), therefore less range. Electric cars only get their decent range at that speed by being heavy compared to their payload (which in turn makes them inefficient).

Second, a car on a motorway only uses about 10 kW of power, something like 50 watts per kilogramme of battery you can put in. The engine is more powerful, but you rarely use it at full power. Our article on Jet Skis mentions that the 2017 model has a 120 kW engine and weighs 250 kg; maybe you could put a 50 kg battery in one of those. As it actually runs close to full power most of the time, that's 2400 watts per kilogramme of battery. The battery will be drained in five minutes. PiusImpavidus (talk) 18:07, 18 October 2024 (UTC)

Much of that weight is the battery itself, and a car does not have to either float, or remain airborne. As yet, battery technology has not yet been developed to routinely combine very large energy storage and low weight, safely: storing a large amount of energy in a small space is always a potential bomb or conflagration. Cutting-edge experimentation (for example in the form of Formula E racing cars and MotoE bikes) is ongoing, and has shown rapid progress year by year. As for why various recreational vehicles in electric form have not caught on – it boils down to lack of public demand; manufacturers would offer such vehicles if there was sufficient demand to make them profitable. {The poster formerly known as 87.81.230.195} 94.6.86.81 (talk) 18:23, 18 October 2024 (UTC)

I still don’t understand why a 250kg vehicle needs a more “powerful” engine than a 2 tonne vehicle. It just doesn’t make sense to me. Could someone explain the physics behind this? Surely there is no doubt to the fact that 2 tonnes takes 8 times as much energy to move as only 250 kg? So why the discrepancy? I mean, if we have the technology to power a 2 tonne vehicle for 200 miles, then why can’t we do the same with a vehicle one eighth of the weight? I struggle to understand the physics of this and it’s messing with my head.

Also, why are people not faking climate change more seriously? Shouldn’t they prioritise cutting gasoline out of their lives as soon as possible? Pablothepenguin (talk) 19:41, 18 October 2024 (UTC)

Heh. Faking seriously? That's an unfortunate typo. But anyway a jet ski, or a RIB for that matter, is for zooming around, bouncing giddily over the waves. It not only has to go fast, it has to go fast in water, overcoming friction by planing. "To plane, especially to initiate planing, the power-to-weight ratio must be high". This kind of hedonism is not typically associated with environmentalism, although I see an image of an electric jet ski, or "electric personal watercraft", positioned opposite Electric_boat#Efficiency. It has an external link and looks suspiciously like an advert, you may want to check that out before I get round to removing it as promotional.  Card Zero  (talk) 20:46, 18 October 2024 (UTC)

I still don’t understand the physics here. You still can’t deny the fact that a 2 tonne vehicle requires eight times as much energy to move as a 250kg vehicle. So, why the big difference in engine power? Surely it is impossible to deny what you can physically see with these numbers. If we can get a 2 tonne vehicle to travel 200 miles on battery power, then what is stopping us from doing the same with a 250kg vehicle? It should only require one eighth of the energy. Pablothepenguin (talk) 00:59, 19 October 2024 (UTC)

If there's no friction, then any tiny force F will move them both the same distance. If we want them to cover the same distance in the same time, a = F/m, so yes, it takes 8 times more. But you should pay attention to the missing f (friction), of which there are many kinds. The watercraft needs more power because it pushes through water. Outboard_motor#Portable says that a 15hp motor (about equivalent to four 50cc scooters) can only move a small dinghy at less than 10 mph.  Card Zero  (talk) 03:14, 19 October 2024 (UTC)

There's quite a big difference between land vehicles and water vehicles. At low speed, a land vehicle mostly suffers from rolling resistance and friction in the drivetrain. This is more or less proportional to weight and independent of speed. A boat mostly suffers from skin drag and wave-making resistance, increasing more or less linearly with speed. As the resistance of the boat has no constant term, it's at low speed much less than that of a land vehicle. That's why freight ships are so efficient.

At high speed this changes. For land vehicles, air drag becomes dominant, roughly increasing with the square of velocity. The speed where this becomes dominant depends on the vehicle, maybe 20 km/h for a bicycle and 70 km/h for some cars. For a boat, the critical point is the hull speed, which depends on the size of the boat. For a kayak it's around 8 km/h, for a big container ship 80 km/h. Once you reach the hull speed, drag increases enormously. For a planing hull it's not as bad as for a displacement hull, but it's still bad. That's why fast boats are such an inefficient way of moving things around. Jet Skis and rigid inflatable boats are designed to work well above their (rather low, because they're small) hull speed, so their drag is huge.

For aeroplanes, drag is proportional to weight and practically independent of speed. If you want to go faster, you go higher, keeping lift and drag constant. The lower density of the air compensates for the higher speed in the drag equation. PiusImpavidus (talk) 11:06, 19 October 2024 (UTC)

Ok, that seems reasonable. Now I want to know more about my first question. For instance, why is a 60 year old plane still expensive? Also, how do price drops work in the first place?

Also, why are petrol go-karts still a thing? Can’t we get rid of them and use batteries instead? Pablothepenguin (talk) 17:33, 19 October 2024 (UTC)

Especially in the US, many people believe that climate change is either a hoax or a natural phenomenon unrelated to human-caused greenhouse gas emissions. Apart from that, the price is an issue. I think gasoline-powered go-karts are substantially cheaper than electric ones. The go-karts rented in competitive racing events organized by commercial go-kart track operators need all to be the same type, so switching to an all-electric fleet is a very costly proposition. Also, gas-powered karts produce a more satisfying vroom-vroom noise (satisfying to the driver).  --Lambiam 06:37, 20 October 2024 (UTC)

On aircraft pricing, this source lists pre-owned aircraft for less than $100,000. However, I would hate to be flying in one and need repairs ... DOR (ex-HK) (talk) 20:43, 19 October 2024 (UTC)

That still sounds like a lot. Why are 60 year old planes still that expensive? I’ve seen brand new cars that cost less than that? Pablothepenguin (talk) 21:26, 19 October 2024 (UTC)

Because (a) they're rare, and (b) old things have appeal beyond their utility – see for example Antique.

With reference to your earlier queries, see Electric boat. {The poster formerly known as 87.81.230.195} 94.6.86.81 (talk) 05:24, 20 October 2024 (UTC)

It's basic economics: supply and demand, whatever the market will bear. If you offer an object for 1,000 dollars and nobody buys it, you can either keep it or reduce the price until it sells. ←Baseball Bugs carrots→ 10:42, 20 October 2024 (UTC)

To return to the electric aircraft question, Misplaced Pages has (of course) an article called electric aircraft. Most commercially available examples are motor gliders, such as the Lange Antares and Pipistrel Taurus, although a few are proper light aircraft, the Pipistrel Velis Electro for example. A number of passenger aircraft are in the pipeline, the 10-seat Scylax E10 being perhaps the nearest to actual service. Alansplodge (talk) 13:43, 21 October 2024 (UTC)

October 20

Average time for inauguration

I stopped editing about topics surrounding the President-elect of Indonesia Prabowo Subianto for a bit. What is exactly the time for the inauguration ceremony? Ahri Boy (talk) 04:04, 20 October 2024 (UTC)

I did not readily find the time schedule for the ceremony. But, curiously, this article, "Indonesia swears in Prabowo Subianto as the country’s eighth president", was posted "Oct 19, 2024 / 11:04 PM CDT". Since CDT is UTC−05:00, it was posted the very same minute you posted the question.  --Lambiam 05:49, 20 October 2024 (UTC)

October 24

Founding members of CARE International, 27 November 1945

Which 22 organisations including Salvation Army founded CARE International in 1945?

Kind regards Sarcelles (talk) 16:02, 24 October 2024 (UTC)

• Misplaced Pages resources for researchers
• Misplaced Pages help forums
• Misplaced Pages reference desk