Wikipedia:Reference desk/Archives/Science/2022 October 11

= October 11 =

Unidentified fruit
Can anybody help identify this fruit on a shrub found at Abbey Gardens in Bury St Edmunds (East of England) today? Fruits are about 2 cm across and slghtly downy, a bit like peach fuzz. A taste test was not unpleasant but inconclusive and I'm still alive at the time of writing. Alansplodge (talk) 16:35, 11 October 2022 (UTC)


 * Quince? Bazza (talk) 16:39, 11 October 2022 (UTC)
 * Ah yes, you may be right. I was thinking that it was far too small to be a quince, but I see that some flowering cultivars - like this one - have smaller fruits. Dissecting the sample I brought home matches the illustration in our article and it is indeed "fragant". Alansplodge (talk) 16:53, 11 October 2022 (UTC)
 * So it may be useful if you happen to be at risk of scurvy (see 2nd paragraph at link). --174.95.81.219 (talk) 07:24, 12 October 2022 (UTC)
 * Also it was allegedly what the serpent used to tempt Eve in the Garden of Eden, at least according to a movie I saw once. Does anyone know what movie?  I think it had Rosie Perez appearing on Jeopardy, with Alex Trebeck appearing as himself, and she answered that question. --Trovatore (talk) 16:23, 12 October 2022 (UTC)
 * Found my own answer -- appears to be White Men Can't Jump. --Trovatore (talk) 16:36, 12 October 2022 (UTC)
 * You might also consider one of the Chaenomeles. DuncanHill (talk) 17:00, 11 October 2022 (UTC)
 * Oh, I see you have linked to one of them. The Flowering Quinces are not cultivars of the Quince, they are a different genus. DuncanHill (talk) 17:03, 11 October 2022 (UTC)
 * We have Quince which are of the same tribe, but Pseudocydonia and Chaenomeles are not, despite all are being known as "quince" in English. I can't see an exact match so far, but won't be losing any sleep if we can't pin down an exact species. Alansplodge (talk) 17:18, 11 October 2022 (UTC)


 * It looks to me like some kind of citrus cultivar rather than a quince. There are hundreds of different citrus fruits (maybe thousands) and while commercial varieties available in western supermarkets account for only a few (lemon, persian lime, key lime, meyer lemon, grapefruit, mandarin, navel orange, tangerine, maybe pomelo and kumquat) there are many more varieties than most people are familiar with.  Maybe a citron or a papeda of some type.  -- Jayron 32 18:40, 11 October 2022 (UTC)
 * Citruses rarely survive the winter, unless brought indoors, in Britain. The leaves are smooth-edged too, which is un-citrus-like. DuncanHill (talk) 18:46, 11 October 2022 (UTC)
 * The stem and leaves are very citrus-like. It is definitely Citrus trifoliata. Thriley (talk) 18:51, 11 October 2022 (UTC)


 * Looks like Citrus trifoliata, a hardy citrus common in England. Thriley (talk) 18:43, 11 October 2022 (UTC)
 * Sounds plausible. I have added a cross-section - it does look a bit citrus-like inside and has the "fuzzy texture" mentioned in our article. Alansplodge (talk) 21:38, 11 October 2022 (UTC)
 * Thank you for the photo. You can see the Juice vesicles found in citrus fruit. Thriley (talk) 21:52, 11 October 2022 (UTC)
 * I am persuaded. Many thanks. Alansplodge (talk) 12:38, 12 October 2022 (UTC)

Energy delivered by a machine gun
I read this online: "kinetic energy of a bullet = k kinetic energy of n bullets = nk According to the law of conservation of energy, the kinetic energy of the bullets must be equal to the work done by a machine gun per second".

So can I write that the energy "E" delivered by a machine gun with a firing frequency "f", "F" = "f" without time, is : "E = kF" ? — Preceding unsigned comment added by Malypaet (talk • contribs) 21:07, 11 October 2022 (UTC)
 * No, you can't. The addition "per second" makes no sense in the "online" statement. Conservation of energy means "kinetic energy = work". When time is brought into this, you talk about power. --Wrongfilter (talk) 08:07, 12 October 2022 (UTC)
 * So if I reformulate, I can only consider the kinetic energy of the group of bullets over one second "E=kF", (even if they were emitted in sequence at different times). But for the machine gun I have to consider its power "P=kf"? On the other hand, for a target (a regid ball with a mass a thousand times greater for example) which receives this energy over one second, it is indeed energy, isn't it? Malypaet (talk) 08:47, 12 October 2022 (UTC)
 * What does "F" stands for? Is it a dimensionless quantity? You ask several questions of the nature of "which is better/more correct?". The answer depends on what you are seeking to achieve, which is not entirely clear. In either case, depending on what is given and what is wanted or needed, one can consider either energy or power, or both. --Lambiam 09:32, 12 October 2022 (UTC)
 * Compared to earlier questions, this time our OP has asked a surprisingly easy question: "can I write...?"
 * Yes! You can write this!  It's  free country, (I think!  I'm not sure what country you're in, but it sounds like it has an alarming amount of machine-gunnery, which causes me to wonder about the relative merits of "freedom" in so-called free countries)... but let's assume (with, perhaps, some loss of generality) that it is a free country.  You can write this mathematical expression!
 * Does it help you to write this expression?
 * Do you find it therapeutic? Does it help you to understand photons, or machine guns?  Does it help you to communicate your insight with others who study photons (or machine guns)?  Does it help you design a better photon, or a better machine (gun?  ...  Please don't - we've got plenty of fine-enough of those machines already!)
 * Really, though, I read a lot of philosophy into the question. For what purpose do you express these ideas?  For a practical one?  If so ... the science reference desk is not a place to participate in practical design and engineering of machines (or guns).
 * Is it for a thought experiment of some kind? If so ... we can point you to better thought experiments, constructed by smart, well-respected authors.  (I did link several introductory texts, above!)
 * Is it some form of artistic expression? If so, I commend it... I think!  I applaud artistic expression, even if I don't particularly subscribe to its aesthetic.  In this case, I interpret it as some kind of reactionary postmodernism extolling the absurdity of technological progress and the self-destructive nature of the human.  But, ... the science reference desk might not be the place for it.  Besides, as they say, viewers impose their own meaning on to art, so... let's not fall victim to pro-institutionalist interpretations.  This is a free country encyclopedia where anyone may contribute.  "Can I write...?"  Yes!  ''But Why?
 * In seriousness, our OP can write any equation they want - some equations are useful, some writings serve to encapsulate useful content, and the rest we call art, I think. Art, in all its forms, including open-form prose on public internet websites.  Art, an abstraction that can provide a medium to reflect complex ideas and stimulate the minds of the viewer... easier to make and yet harder to define than science...
 * Nimur (talk) 16:16, 12 October 2022 (UTC)