I… doing think this works. You expect me to count the dog as a person in the bottom-left panel, but disregard his existence in all the others?
I… doing think this works. You expect me to count the dog as a person in the bottom-left panel, but disregard his existence in all the others?
So we might think: a cube falling through a floor portal and flying out another floor portal right next to it, kinda looks like how a bouncy ball bounces off the floor, and should apply forces on the floor similar to that - an elastic collision. Unfortunately, this brings us right back to conservation of momentum, which didn’t work out. But maybe I just did it wrong? Maybe, if done more carefully, conservation of momentum can work without being dependent on the reference frame?
I genuinely don’t know yet. Time to bring out the calculus.
We have:
M = the mass attached to the portal (e.g. the floor)
V = the velocity of M
V’ = dV/dt = the acceleration of M (assuming no other forces)
F = MV’ = the force applied on the portal
m’ = dm/dt = the rate of mass entering the portal
v = the velocity of the mass entering the portal
If we assume conservation of momentum (our old nemesis), the force applied on the portal should be the same as the momentum taken from the mass entering the portal:
F = m’v
But now we’re back to the case from before, where the choice of reference frame changes the outcome! We’re not having that. So I hereby decree:
The force applied upon a portal by a mass entering it must be calculated by conservation of momentum in the intertial reference frame of the portal itself at the instant under examination.
This gives us, effectively: F = m’(v-V)
Now THAT’S something we can work with!
Note that this formula also works for the exit portal. In that case, m’ is negative.
A curious result follows.
For the entry portal, m’ is positive, and (v-V) is a vector pointing into the portal. (This must be the case, otherwise the mass would be exiting the portal). Therefore, the force would be pushing the portal into the wall.
For the exit portal, m’ is negative, and (v-V) points out of the portal, therefore the portal again would be pushed into the wall.
The result: whenever anything passes through a portal, both ends always get pushed in the same direction.
So, back to my thought experiment.
If a portal attached to a free-falling panel falls onto a cube, the cube’s entry into it would brake its fall to some extent. However, this wouldn’t be the only force in play.
As I said in my previous comment, forces applied between the two halves of an object going through a portal, get applied to the portal itself. In practice, this mostly means tension and compression forces. In the static analysis from before, it was compression.
As the panel is falling onto the cube, a part of the cube is already out the other side and moving away the portal. If the panel has slowed, this would apply a pulling force (tension) on the part of the cube that still hasn’t made it in. This tension force actually compels the portal, and the panel it’s attached to, to speed up towards the ground.
So, in total, would the panel be slowed, accelerated, or unaffected? Maybe the forces cancel out and it just continues on its normal freefall? I don’t know yet. Would need to do more math.
Okay, after thinking about this a while, I’ve decided that conservation of momentum just doesn’t work, unless the portal actually absorbs the mass of every object passing through it, which would probably cause its own set of contradictions.
Instead, I think forces that act through the portal are applied to the portal. What do I mean by this? Well, take this classic case of a cube floating halfway through two floor portals:
____ ____
| | | |
___++++++++++______----------___
(sorry, can’t do better than ASCII art right now)
The system has reached equilibrium, and nothing is moving. Both halves of the cube are being pulled down by gravity, but cancel each other out by applying a normal force on each other right at the portal interface. What I’m claiming is that this normal force is applied to the portals, which ultimately transfer it to the floor. If this entire floor was a scale, it would measure the calibrated weight of the Weighted Storage Cube.
But this is the static analysis. What happens when objects are in motion? To be continued…
The answer is definitely B (see other comments), but I think the more interesting question is, how does it affect the portals themselves and the surfaces they’re attached to?
When the portals are attached to a solid unmovable wall (as in the games), we can pretty much ignore the forces acting upon the wall as they will just be automatically cancelled out by the normal force. But the same does not apply for portals attached to detached panels. Let’s say that instead of a piston pushing down, the portal is attached a free-falling panel with the portal facing down.
We are inclined to assume that as the portal falls onto the cube, it feels no force, as if it fell through air or through a vacuum. But is that really the case? Maybe instead, the falling portal experiences resistance from the cube? Or even, actually, an accelerating force?
Let’s assume conservation of momentum at each end of the portal. That is, in the general case: if the portal (which we assume has no mass) is attached to an object with mass M and velocity V, and “swallows” a cube or other object with mass m and velocity v, and at the end of this interaction the portal-surface object with mass M has velocity V’, then we expect:
M × V’ = (M × V) + (m × v)
Mass is not conserved because the cube was transferred to the other portal.
Solve for V’:
V’ = V + (m/M) v
This is a strange result. The cube’s momentum is imparted into the portal, but the result would be different depending on our reference frame. From a reference frame tracking the cube pre-interaction, v = 0 (by definition) and so V’ = V, the portal-surface object has no change in velocity. But in any other reference frame, it does.
Physics can’t be affected by reference frame (thanks, relativity) so this analysis must be wrong.
… I’ll keep thinking on this.
The “ragebait answers only” in the OP is the only thing stopping me from actually raging at everyone saying A. I am giving them all the benefit of the doubt, they’re deliberately saying the wrong answer.
Everyone saying B missed the assignment and answered accurately.
Now there’s a high quality ragebait answer


I’m not on it, but I’d be surprised if I was. I’m mostly a commenter, and don’t often get into the topics that would put one on the list. Still, from all the reactions I had to check!


Opens fine in Voyager, here’s a quote:
Tesseract is/was an alternative frontend for Lemmy sites. Its developer — asimons04 — hid malware in it. It would secretly download an obfuscated ban list with instances, communities, and people that asimons04 wanted to personally discriminate against and it would silently shadowban them from any site that used Tesseract.
The bans were heavily anti-fash leftists and queer folks, including yours truly.
This was discovered through some community sleuthing in the last several days. Asimons04 has since
deleted their repos and accounts and disappearedmoved repos to break forking and posted an unhinged rant to dubvee.@db0@lemmy.dbzer0.com has forked Tesseract since it had some nice features and they seem to be working on thoughtfully removing the malware.
Those finding their name on the list are treating it as a badge of honor, since it shows that asimons04 was a conniving fascist bigot.
The rabbit hole begins here.
https://lemmy.world/post/49778353
Translation from… An older version of English? I’m pretty sure that distinction is not in the original Hebrew.


Just curious (I don’t have a Steam Machine and don’t plan to get one), doesn’t Steam fight for control of the LEDs if you run both Steam and OpenRGB at the same time?


Yup, OpenRGB has audio visualization support in the Effects plugin: https://openrgb.org/plugin_effects.html


Oh yeah, OpenRGB is awesome— oh, it’s you :P


Playing chess. Stockfish is a hungry beast.
Here are the things I love about Mint:
Here are the reasons I switched to CachyOS:
I do have some qualms about CachyOS, specifically I feel like Shelly (their choice of GUI package manager) is undercooked and not ready to ship as default. You don’t have to use it though.
I’m going to stick with CachyOS for now, mostly because it’s just working for me and I don’t feel a strong reason to switch. I hear that Mint/Cinnamon is getting closer to Wayland, which might make for a good time to switch back to it. Or I’ll just stick with what’s working for me until it doesn’t.
I have a regular donation going to Linux Mint. But I’ve kinda switched my main PC over to CachyOS a while back, so technically I’m not paying for the distro I’m using.
I still think Mint is the best. Just kind of confused about where my money should be going.


One might say the Deck still isn’t fully baked. I got mine a few months ago, so well after it launched, and there were still some rough edges. For example, I wasn’t able to redeem the OLED goodies (startup animation and keyboard theme). Steam Support advised me to switch to the SteamOS beta at the time, which worked. So the release version of SteamOS had a known redemption bug for months, likely to affect a large number of new users? Sure it’s a small thing, but exactly what I mean by not fully baked.
I have some other nitpicks with it but overall I’ll admit it works quite well.


This is the relevant quote:
“In the current state of things, mangaka are not allowed to use AI. But using AI actually drives up the quality by a mile. So doesn’t that mean it would be best to not draw the manga now? Maybe they suddenly lift the ban [on AI] next year, so it might be better to start drawing after that happens. I’m currently on standby in that sense,” Asano says. Though he didn’t elaborate if or to what extent he hypothetically plans to use AI, he said that using it could significantly speed up the modeling process.


From my understanding, the first and second parties are the seller (Valve) and the buyer (you). They are the two who have a contract between them. A third party, then, is any party which isn’t signed on the contract. That is, an outsider to the contract.
Any other meaning of second party is probably a back-formation from a misunderstanding of the terms 1st and 3rd party.
Disclaimer: I literally have no idea what I’m talking about
I love this. Certain surgeries absolutely involve some amount of “plumbing”, e.g. connecting the blood vessels in a pig heart transplant (I think they even refer to it as plumbing, perhaps informally). And I think it’s very accurate to say that plumbers, electricians etc. are to houses as surgeons are to living creatures.