# Factual Questions **URL:** https://boards.straightdope.com/c/factual-questions/9.md?page=216 [Latest](https://boards.straightdope.com/latest.md) · [Categories](https://boards.straightdope.com/categories.md) · [Tags](https://boards.straightdope.com/tags.md) **Page:** 217 --- ## [Electric Garage Door Opener?](https://boards.straightdope.com/t/electric-garage-door-opener/962116)
**Author:** [@19USMC69](https://boards.straightdope.com/u/19USMC69)\ **Replies:** 21\ **Last updated:** [April 5, 2022, 5:57pm UTC](https://boards.straightdope.com/t/electric-garage-door-opener/962116 "2022-04-05T17:57:57Z")
Most have sensors at the bottom edge that shuts down the motor when the beam is broken. If, for instance, the door is opening and a physical obstruction physically stops the door, will the motor shut down. Thx. --- ## [Gold in 1.875 gram bars?](https://boards.straightdope.com/t/gold-in-1-875-gram-bars/962114)
**Author:** [@brossa](https://boards.straightdope.com/u/brossa)\ **Replies:** 10\ **Last updated:** [April 5, 2022, 10:09am UTC](https://boards.straightdope.com/t/gold-in-1-875-gram-bars/962114 "2022-04-05T10:09:04Z")
I just watched a YouTube video of the production of small gold bars in a Korean gold exchange. The final commercial product was a little gold piece in a laminated card. What has me baffled is that the standard weight of … --- ## [What would \*actually\* happen if you hooked someone up to a coffee IV?](https://boards.straightdope.com/t/what-would-actually-happen-if-you-hooked-someone-up-to-a-coffee-iv/962124)
**Author:** [@ekedolphin](https://boards.straightdope.com/u/ekedolphin)\ **Replies:** 36\ **Last updated:** [April 5, 2022, 7:51am UTC](https://boards.straightdope.com/t/what-would-actually-happen-if-you-hooked-someone-up-to-a-coffee-iv/962124 "2022-04-05T07:51:21Z")
We’ve all joked about “hook me up to a coffee IV and save me a couple extra steps; I’m exhausted this morning”, words to thaf effect. But what would happen if you actually hooked someone up to a coffee intravenous drip?… --- ## [What happens when two or more fans are in a row?](https://boards.straightdope.com/t/what-happens-when-two-or-more-fans-are-in-a-row/962150)
**Author:** [@Johnny\_Bravo](https://boards.straightdope.com/u/Johnny_Bravo)\ **Replies:** 17\ **Last updated:** [April 5, 2022, 5:54am UTC](https://boards.straightdope.com/t/what-happens-when-two-or-more-fans-are-in-a-row/962150 "2022-04-05T05:54:47Z")
I’m sure I’m using some incorrect terminology here, so please forgive any egregious errors. Say I have a wall unit blowing cold air. I place a portable fan several feet in front of the unit so that the cold air blows in… --- ## [Amazon communication](https://boards.straightdope.com/t/amazon-communication/962201)
**Author:** [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Replies:** 7\ **Last updated:** [April 5, 2022, 3:15am UTC](https://boards.straightdope.com/t/amazon-communication/962201 "2022-04-05T03:15:53Z")
I don’t order from Amazon very often. Once every half year or so. So I’m not all that up on how to do things there. Yesterday, I got a delivery from Amazon that I thought didn’t come. They sent me a notice that they’d d… --- ## [Vision jumpy only for specific frequencies?](https://boards.straightdope.com/t/vision-jumpy-only-for-specific-frequencies/962252)
**Author:** [@Delayed\_Reflex](https://boards.straightdope.com/u/Delayed_Reflex)\ **Replies:** 3\ **Last updated:** [April 5, 2022, 12:52am UTC](https://boards.straightdope.com/t/vision-jumpy-only-for-specific-frequencies/962252 "2022-04-05T00:52:20Z")
I wasn’t quite sure how to title this question, but it’s an odd phenomenon that I’ve noticed - when using my electric toothbrush, the light on my humidifier will appear to jump around, moving rapidly up and down (it look… --- ## [Metro-North trains (NYC area): why engines on the north end of train?](https://boards.straightdope.com/t/metro-north-trains-nyc-area-why-engines-on-the-north-end-of-train/961984)
**Author:** [@toadspittle](https://boards.straightdope.com/u/toadspittle)\ **Replies:** 12\ **Last updated:** [April 5, 2022, 12:20am UTC](https://boards.straightdope.com/t/metro-north-trains-nyc-area-why-engines-on-the-north-end-of-train/961984 "2022-04-05T00:20:07Z")
I took Metro North from Poughkeepsie station to Grand Central for years, but I was usually dashing at top speed to catch a train or get a good seat; I never noticed which end of the train the engines are on. But we’ve b… --- ## [Why do non-radioactive materials become radioactive?](https://boards.straightdope.com/t/why-do-non-radioactive-materials-become-radioactive/962218)
**Author:** [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Replies:** 14\ **Last updated:** [April 4, 2022, 9:59pm UTC](https://boards.straightdope.com/t/why-do-non-radioactive-materials-become-radioactive/962218 "2022-04-04T21:59:06Z")
Question inspired by IMHO thread about the irradiated Russian soldiers (although I’ve wondered about this before). When “ordinary” non-radioactive materials get exposed to radiation, why do they become radioactive? The… --- ## [How does 180º coffee not scald the mouth?](https://boards.straightdope.com/t/how-does-180-coffee-not-scald-the-mouth/962161)
**Author:** [@nelliebly](https://boards.straightdope.com/u/nelliebly)\ **Replies:** 30\ **Last updated:** [April 4, 2022, 9:50pm UTC](https://boards.straightdope.com/t/how-does-180-coffee-not-scald-the-mouth/962161 "2022-04-04T21:50:47Z")
Starbuck’s “extra hot” coffee is 180º. I think McDonald’s coffee is still 180º. At 140º, water will scald skin within 3 seconds. I’m not sure how fast 180º hot water causes burns, but I’m guessing it’s in less time than … --- ## [What is the biggest flat place in the world?](https://boards.straightdope.com/t/what-is-the-biggest-flat-place-in-the-world/962057)
**Author:** [@Danger\_Man](https://boards.straightdope.com/u/Danger_Man)\ **Replies:** 18\ **Last updated:** [April 4, 2022, 9:38pm UTC](https://boards.straightdope.com/t/what-is-the-biggest-flat-place-in-the-world/962057 "2022-04-04T21:38:30Z")
I realize that this depends heavily on how you define flat. But let’s say it is anywhere you can drive a regular car in any direction without chance of getting stuck. --- ## [Red/blue shifting - not astronomy related](https://boards.straightdope.com/t/red-blue-shifting-not-astronomy-related/962130)
**Author:** [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Replies:** 10\ **Last updated:** [April 4, 2022, 7:15pm UTC](https://boards.straightdope.com/t/red-blue-shifting-not-astronomy-related/962130 "2022-04-04T19:15:48Z")
It’s popular these days to see images the have a red and blue shift or ghosting. I realize a lot of it nowadays is done on purpose but is there an historic precedent like bad TV reception or something? EXAMPLE - skip to… --- ## [Gravitational Lensing Question](https://boards.straightdope.com/t/gravitational-lensing-question/961815)
**Author:** [@Jackknifed\_Juggernaut](https://boards.straightdope.com/u/Jackknifed_Juggernaut)\ **Replies:** 17\ **Last updated:** [April 3, 2022, 12:58am UTC](https://boards.straightdope.com/t/gravitational-lensing-question/961815 "2022-04-03T00:58:33Z")
What proportion of the stars that we can see are impacted by gravitational lensing, to the point that we see multiple versions of them. I had the thought that perhaps there are fewer stars out there than we observe, si… --- ## [Sucking eggs-with your RECTUM?](https://boards.straightdope.com/t/sucking-eggs-with-your-rectum/90669)
**Author:** [@cynic](https://boards.straightdope.com/u/cynic)\ **Replies:** 15\ **Last updated:** [April 2, 2022, 11:02pm UTC](https://boards.straightdope.com/t/sucking-eggs-with-your-rectum/90669 "2022-04-02T23:02:32Z")
OK, I was having a conversation with a co-worker and somehow we got onto the topic of what can happen to you when you overexert yourself sexually. He told me that in many Latin American countries (he’s Mexican-American),… --- ## [Technical question about UPS, Fedex, USPS package tracking](https://boards.straightdope.com/t/technical-question-about-ups-fedex-usps-package-tracking/962119)
**Author:** [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Replies:** 15\ **Last updated:** [April 2, 2022, 9:02pm UTC](https://boards.straightdope.com/t/technical-question-about-ups-fedex-usps-package-tracking/962119 "2022-04-02T21:02:28Z")
Does anyone know about the internal workings of the system used for tracking for these package delivery services? Specifically, I’m wondering how the data gathered in the field by drivers gets to the shipper and custome… --- ## [With an all-powerful computer and knowledge of the position of every particle in the world, could one reconstruct the placement of Lincoln's hat the moment he was shot?](https://boards.straightdope.com/t/with-an-all-powerful-computer-and-knowledge-of-the-position-of-every-particle-in-the-world-could-one-reconstruct-the-placement-of-lincolns-hat-the-moment-he-was-shot/961694)
**Author:** [@MozeJose](https://boards.straightdope.com/u/MozeJose)\ **Replies:** 55\ **Last updated:** [April 2, 2022, 7:04pm UTC](https://boards.straightdope.com/t/with-an-all-powerful-computer-and-knowledge-of-the-position-of-every-particle-in-the-world-could-one-reconstruct-the-placement-of-lincolns-hat-the-moment-he-was-shot/961694 "2022-04-02T19:04:26Z")
I just finished watching the show Devs. A big part of the show is If free will exists, it would be impossible for a computer to predict the future. However, would it be possible to reconstruct the past since the comput… --- ## [Why does it take typed letters time to appear on screen; sometimes several seconds?](https://boards.straightdope.com/t/why-does-it-take-typed-letters-time-to-appear-on-screen-sometimes-several-seconds/961318)
**Author:** [@ekedolphin](https://boards.straightdope.com/u/ekedolphin)\ **Replies:** 14\ **Last updated:** [April 2, 2022, 5:48pm UTC](https://boards.straightdope.com/t/why-does-it-take-typed-letters-time-to-appear-on-screen-sometimes-several-seconds/961318 "2022-04-02T17:48:05Z")
Why does it take so much time, sometimes, for letters to appear after I type them? It’s not just on this site, but on other message boards. --- ## [Please diagnose my sick avocado plant](https://boards.straightdope.com/t/please-diagnose-my-sick-avocado-plant/961861)
**Author:** [@nelliebly](https://boards.straightdope.com/u/nelliebly)\ **Replies:** 8\ **Last updated:** [April 2, 2022, 12:53pm UTC](https://boards.straightdope.com/t/please-diagnose-my-sick-avocado-plant/961861 "2022-04-02T12:53:24Z")
I had no intention of growing an avocado tree, but some months back, I cut open an avocado and found the pit cracked and a little root inside. I didn’t have the heart to throw it away, so I put it in a glass of water, an… --- ## [Can Ukraine sue Russia for damages when the war is over?](https://boards.straightdope.com/t/can-ukraine-sue-russia-for-damages-when-the-war-is-over/961921)
**Author:** [@DaveRaver](https://boards.straightdope.com/u/DaveRaver)\ **Replies:** 9\ **Last updated:** [April 2, 2022, 6:23am UTC](https://boards.straightdope.com/t/can-ukraine-sue-russia-for-damages-when-the-war-is-over/961921 "2022-04-02T06:23:30Z")
Seems like they’d have a good case. --- ## [Do crossover SUV's sway more or less in the wind than short hatchbacks?](https://boards.straightdope.com/t/do-crossover-suvs-sway-more-or-less-in-the-wind-than-short-hatchbacks/962123)
**Author:** [@JakeRS](https://boards.straightdope.com/u/JakeRS)\ **Replies:** 1\ **Last updated:** [April 1, 2022, 8:39pm UTC](https://boards.straightdope.com/t/do-crossover-suvs-sway-more-or-less-in-the-wind-than-short-hatchbacks/962123 "2022-04-01T20:39:26Z")
Like many people here in Europe, I drive a small city hatchback, a VW Lupo, a 3.5 meter A-segment box. On paper the drag coefficient is surprisingly good at 0.32 for a 20+ year old hatchback, however in reality turbulen… --- ## [So what's the deal with not pressing charges](https://boards.straightdope.com/t/so-whats-the-deal-with-not-pressing-charges/961840)
**Author:** [@griffin1977](https://boards.straightdope.com/u/griffin1977)\ **Replies:** 100\ **Last updated:** [April 1, 2022, 8:33pm UTC](https://boards.straightdope.com/t/so-whats-the-deal-with-not-pressing-charges/961840 "2022-04-01T20:33:36Z")
Inspired by certain events at the Oscars last night. What’s the deal with “not pressing charges” (as seems to be the case w.r.t. Chris Rock in this incident). Both theoretical and practically. In theory is there any s… --- ## [First (maybe just early?) "Holy shit" moment in evolutionary timeline?](https://boards.straightdope.com/t/first-maybe-just-early-holy-shit-moment-in-evolutionary-timeline/961901)
**Author:** [@Roger\_That](https://boards.straightdope.com/u/Roger_That)\ **Replies:** 38\ **Last updated:** [April 1, 2022, 7:49pm UTC](https://boards.straightdope.com/t/first-maybe-just-early-holy-shit-moment-in-evolutionary-timeline/961901 "2022-04-01T19:49:09Z")
I assume that for a long time people simply had no idea how long the universe, the earth, life, human life, etc. existed, so either they went with “Who knows? Dumb question” or “This very smart person says it’s x long, s… --- ## [What's the status of the part of Russia east of Crimea?](https://boards.straightdope.com/t/whats-the-status-of-the-part-of-russia-east-of-crimea/961979)
**Author:** [@FlikTheBlue](https://boards.straightdope.com/u/FlikTheBlue)\ **Replies:** 14\ **Last updated:** [April 1, 2022, 12:47pm UTC](https://boards.straightdope.com/t/whats-the-status-of-the-part-of-russia-east-of-crimea/961979 "2022-04-01T12:47:09Z")
One of the things that is mentioned frequently as a Russian objective of the invasion is wanting a land connection to Crimea. Looking at Apple Maps, it looks to me like Crimea is almost an island. There’s a couple of v… --- ## [Chernobyl Status](https://boards.straightdope.com/t/chernobyl-status/942647)
**Author:** [@19USMC69](https://boards.straightdope.com/u/19USMC69)\ **Replies:** 10\ **Last updated:** [April 1, 2022, 2:53am UTC](https://boards.straightdope.com/t/chernobyl-status/942647 "2022-04-01T02:53:20Z")
Just watched a documentary on the 1986 disaster. It ended with several countries having built and installed a huge “cover” for it. But it also said this “cover” will only buy more time. What’s the current status of the … --- ## [Any way to prevent an Instagram from seeing my Instagram followers and following?](https://boards.straightdope.com/t/any-way-to-prevent-an-instagram-from-seeing-my-instagram-followers-and-following/961505)
**Author:** [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Replies:** 1\ **Last updated:** [March 22, 2022, 4:38pm UTC](https://boards.straightdope.com/t/any-way-to-prevent-an-instagram-from-seeing-my-instagram-followers-and-following/961505 "2022-03-22T16:38:54Z")
I’m in a weird situation where I want to remain connected with someone on IG yet at the same time there seems to be no way to prevent them from viewing my own followers and following. Anyone know of a way to make this wo… --- ## [What was the final danger resolved for the Apollo mission?](https://boards.straightdope.com/t/what-was-the-final-danger-resolved-for-the-apollo-mission/961588)
**Author:** [@Roger\_That](https://boards.straightdope.com/u/Roger_That)\ **Replies:** 51\ **Last updated:** [March 31, 2022, 8:15pm UTC](https://boards.straightdope.com/t/what-was-the-final-danger-resolved-for-the-apollo-mission/961588 "2022-03-31T20:15:17Z")
And when was it resolved? By “resolved” I mean when did NASA decide that it would be reasonably safe for men to walk on the moon’s surface? Presumably, a long time before 1969, we had figured out that the moon had no b… --- ## [Definition of "displacement" in w = f x d](https://boards.straightdope.com/t/definition-of-displacement-in-w-f-x-d/961980)
**Author:** [@Cayuga](https://boards.straightdope.com/u/Cayuga)\ **Replies:** 32\ **Last updated:** [March 31, 2022, 5:48pm UTC](https://boards.straightdope.com/t/definition-of-displacement-in-w-f-x-d/961980 "2022-03-31T17:48:07Z")
Here’s what I know: Work is equal to the force applied to an object times the displacement of the object. (To keep things simple, I’m assuming that the force is applied in the direction of the displacement — no cos th… --- ## [Why has no one invented a good alternative to cigarettes or alcohol?](https://boards.straightdope.com/t/why-has-no-one-invented-a-good-alternative-to-cigarettes-or-alcohol/961867)
**Author:** [@MarkSh](https://boards.straightdope.com/u/MarkSh)\ **Replies:** 60\ **Last updated:** [March 31, 2022, 1:28pm UTC](https://boards.straightdope.com/t/why-has-no-one-invented-a-good-alternative-to-cigarettes-or-alcohol/961867 "2022-03-31T13:28:08Z")
Christopher Hitchens was an atheist and political writer who used to drink alcohol and smoke cigarettes all the time. He said that he did this because life is boring. that’s the same reason I smoke a pack of cigarettes … --- ## [Why did Putin demand that Russian gas be paid for in rubles?](https://boards.straightdope.com/t/why-did-putin-demand-that-russian-gas-be-paid-for-in-rubles/961658)
**Author:** [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Replies:** 17\ **Last updated:** [March 31, 2022, 10:03am UTC](https://boards.straightdope.com/t/why-did-putin-demand-that-russian-gas-be-paid-for-in-rubles/961658 "2022-03-31T10:03:18Z")
The article below says that Poland refuses to pay for Russian gas using rubles. Poland notes the terms of the contract does not specify they pay in rubles. Ok, but, presumably, Poland is still paying Russia in some fas… --- ## [P.1/P.38 holster belt adapter](https://boards.straightdope.com/t/p-1-p-38-holster-belt-adapter/962028)
**Author:** [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Replies:** 2\ **Last updated:** [March 31, 2022, 3:48am UTC](https://boards.straightdope.com/t/p-1-p-38-holster-belt-adapter/962028 "2022-03-31T03:48:32Z")
I have a West German police holster like this one. As you can see in the picture, it doesn’t go onto a belt. This image shows and adapter for an ALICE belt. Am I correct in assuming that the holes in the adapter fit … --- ## [Freight Trains-Containers-Arizona/California](https://boards.straightdope.com/t/freight-trains-containers-arizona-california/961925)
**Author:** [@19USMC69](https://boards.straightdope.com/u/19USMC69)\ **Replies:** 12\ **Last updated:** [March 30, 2022, 10:52pm UTC](https://boards.straightdope.com/t/freight-trains-containers-arizona-california/961925 "2022-03-30T22:52:26Z")
I find myself on Interstate 8 between Phoenix and LA on a fairly regular basis. Paralleling the interstate I see very long trains with sea containers, some heading east and some west. I figure the containers heading eas… [Previous page](https://boards.straightdope.com/c/factual-questions/9.md?page=215) [Next page](https://boards.straightdope.com/c/factual-questions/9.md?page=217)