# Search results

1. ### MATLAB FFT interpretation of time vector (simple)

Yes. As I understand it, you are tracking the vertical position of a one-pixel-size feature. For simplicity, I will assume you are not dealing with an interlaced image. So your samples are vertical positions - likely image line numbers. And your sampling rate will be your video frame rate...
2. ### MATLAB FFT interpretation of time vector (simple)

Video data is three-dimensional: horizontal, vertical, and time. None of the examples deal with images - let alone video data. It is certainly possible to do a 3-d FFT, but I doubt that is your intent. Tell us more about this video and exactly what you want to extract from it. Is it a pendulum...
3. ### I Two axis motion for any vehicle

When an airplane (hopefully an aerobatic plane) does a snap roll or spin, it is doing these kind of combinations. At the start of the spin, the nose of the aircraft drops down and to the side with a definite yaw component. But once fully developed, the axis of rotation is primarily up and to...
4. ### I Uncertainty = our ignorance or intrinsic to reality?

First, you're paraphrasing the Heisenberg Uncertainty Principle very imprecisely. A statement of the principle is provided in the wiki article as follows: So you can measure both position and momentum simultaneously, but there is a limit on the combined precision of those two measurements -...
5. ### I Uncertainty = our ignorance or intrinsic to reality?

Heisenberg Uncertainty is intrinsic to Physics. A complete description of a system takes this limit into account. It is not an issue of ignorance - it is a real limit.
6. ### Would expired toothpaste lose its functionality?

It's good to know what the functionality is before asking if it can be lost. Here's what one dentist chain (Altima) has to say about it: Most of the objectives for brushing your teeth are accomplished just by brushing - even with only water. And if your water already has fluoride, you can...
7. ### Game theory: competitive auction for the money in a chest

There are different assumptions that can be made about your opponent and about your objective. First, the other player isn't referred to as an "opponent" until part b. So I will call them a "game mate". Second: The rules do not say that you are playing this multiple times. On the face of it...
8. ### B What if tachyons are detected?

... because there would not be "drag" evident for moving objects. But tachyons would propagate gravitational waves faster than light. And you would still need to consider whether the collisions are elastic or inelastic. If they're elastic, the "gravity" doesn't work because you would get the...
9. ### B What if tachyons are detected?

The problem comes with transmitting information at faster-than-light speeds. If that can be done, a system can be set up to transmit information back in time - hence the allusion to "The Sting" by @anorlunda . Detecting a tachyon could be problematic. How would you even verify that what you...
10. ### I Does time drive Black Hole travelers into a central singularity?

Only in Euclidean space. I was trying to determine exactly how consequential that space curvature was. As it turns out, ## 2\pi r## only works when there is no mass. So that satellite that falls back and forth through the tunnel will take longer to return to its starting position that the one...

12. ### I Does time drive Black Hole travelers into a central singularity?

Even if only one of you "disliked" diameter, I would have presumed it to be problematic for good reasons. Areal "radius" totally works for me. I was presuming the gravitational field was following the "inverse square" law based on area. I found this: (No, not Feynman) And that's one of the...
13. ### I Does time drive Black Hole travelers into a central singularity?

Yes. I'm starting to have questions about my question. The fact that the "time vector" points in towards the mass is what makes gravity work. By "time vector" I mean the direction along the space-time line that an object will follow when in free fall. So both you and @Dale don't like the...
14. ### I Does time drive Black Hole travelers into a central singularity?

I am trying to get a better feel for it. So I'm for specific contradictions to my thinking. I tend to think of gravity as light - but there's no Doppler effect - so they really are not alike. I've definitely seen those charts before, I'm looking more for how they work than what they say.
15. ### I Does time drive Black Hole travelers into a central singularity?

Since my understanding of these geometries is wrong, I'll do this in numbered steps - the easier to correct my logic. I think the big problem I have is with the time dimension. There seems to be a presumption that the time vector will drive a falling object into a central singularity. But how...
16. ### I Deterministic wind down of the Universe under MWI or Copenhagen?

If you can describe an experiment that could be performed in principle that would differentiate between MWI and Copenhagen, then MWI would become MWT (Many-Worlds Theory). By definition, an interpretation is simply a different way of describing the same experimental results. That said, I am...
17. ### I Object encapsulation

What's so special about an equation? Why not write the information in paragraph form?
18. ### B Question about Gravity and my hands

Perhaps they feel heavier. This isn't a Physics question.
19. ### I Deterministic wind down of the Universe under MWI or Copenhagen?

To answer in the spirit of the question, the Many-World interpretation is an interpretation and therefore should not be different from the Copenhagen interpretation. Both should result in the analogous results as far as determinism is concerned. The basic problem is to create a testable...
20. ### I Deterministic wind down of the Universe under MWI or Copenhagen?

With the Many-World Interpretation, rerunning the universe will give you the same set of states and the same set of "you"s. Since you don't get to choose which you is you, the determinism is pointless. The Copenhagen Interpretation does not allow you to rerun the universe. That would be a...
21. ### I Question about Grover's algorithm

First, I'm not sure that it is used in practice. The "oracle" is part of the Quantum Circuitry that determines exactly what problem is to be solved. So in order to use Grover's algorithm, you need to write another algorithm that is specific to the problem you are attacking. For example, let's...
22. ### COVID Covid Delta variant

Since we're citing the reports from "18 US intelligence agencies", I think we might want to take a look at exactly what these agencies are. As it happens, the US Director of National Intelligence has posted a membership list of such organizations which numbers - you guessed it: 18. But before...
23. ### Atypical demonstration of ground effect

As @berkeman suggested, a definition for "ground effect" was established long before the problem that helicopters can have with exhaust. And it applies to both powered aircraft and sail planes - during rotation and especially during the landing phase.
24. ### COVID Covid Delta variant

That's was my first thought - but at the risk of Sheldon Cooper 1 advising Sheldon Cooper 2: - at 8:20: "If we don't find out soon, we may not find out ever (and notice his continuing dismay)." - at 9:30: "So basically what we're saying is here is the balance of opinion in American intelligence...
25. ### COVID Covid Delta variant

In New England, the vaccination rate is roughly 70% and hospitals are not overly strained by COVID. This is in great contrast to south-eastern US. People at very high risk need to take exceptional measures to avoid Delta. If society decides to assist them at the "endemic" level (not just their...
26. ### COVID Covid Delta variant

I believe your Math is incomplete. You are comparing a 100% chance of getting Delta while recently vaccinated against an unspecified chance of getting any variant at any time. I was actually going to try to list off the decision-making Math here - but it gets pretty complicated pretty fast...
27. ### COVID Covid Delta variant

Covid-19 is known to spread by respiration but is only presumed to spread by fomites. So licking door knobs would be unreliable at best. It's not even clear whether kissing would work. But asking them to sing for you .. What keeps Covid from being a "regular virus" is that it is very unlike...
28. ### COVID Covid Delta variant

If you have already had your 2 mRNA vaccinations, would a Delta infection be a good booster against other Covid-19 variants? I would claim that the objective is to have a world population that is as exposed to COVID-19 as it is to (other) seasonal flu viruses - so that a COVID-19 infection is...
29. ### Atypical demonstration of ground effect

Obviously, I was not in on the decision - but I can easily understand it. Getting to orbit with a mass simulator is a major milestone and is critical to the organizations survival. In this case, Astra Space had just gone public and had raised substantial capital largely on the near-miss on...
30. ### Atypical demonstration of ground effect

With a pentagon arrangement of the engines, expect all 5 are gimbaled. Given the velocity (near zero), there is very little inefficiency. You need to keep the thrust vector through the center of gravity. To do that with a missing engine, the body of the rocket needs to be yawed away from the...