Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - xasop

Pages: [1] 2 3 ... 107  Next >
1
The velocities of two moving object are, by definition, relative to one another.
Incorrect.

The relative velocities of two objects going in the same direction relative to one another will be different than two objects going in different directions relative to one another/i]. Two moving objects will either be moving in the same direction relative to one another or in different directions relative to one another[/i].  Both of those statements are true whether anybody is measuring or observing them or not. They are objective facts.
Now you're being not even wrong. What is "going in different directions relative to one another" even supposed to mean? The velocity of an object relative to itself is zero, and the zero vector has no direction, so the other object can't be moving in the same or a different direction.

My bad.  I misstated, however, the calculations I provided are correct. I provided online calculators if you don’t trust the math.
It's not that I don't trust the maths, it's that there's nothing for me to trust (or not). You haven't explained what model you used to derive these numbers. Numbers on their own are not science.

What’s more those different observers would see the objects meet at different times.
That is not physically possible, unless your observers are moving at relativistic speeds. In classical mechanics, the duration of an event is not observer-dependent. This result should be a huge red flag that your method (whatever it is, since you still haven't told us that part) is invalid.

In RE, with gravity at 9.8m/s2 and air resistance of .24, a skydiver will descend from 533m to the ground in 15s.  In FE then, with UA at 9.8m/s2 and air resistance/thrust of .24, the skydiver should ascend from 1000 feet to 1533m in the same 15s.
Why are you assuming the skydiver moves up in FET at the same rate as they would fall in RET? Air isn't a solid, it won't cause acceleration of the same magnitude as gravity until terminal velocity is reached. Until you fix this broken assumption, all your conclusions will remain incorrect.

Also, please stop mixing different units. I have generously assumed that by "1000 feet" you meant 1000 metres in this post, but you keep switching between SI and customary units with zero explanation provided.

2
I wasn't talking about velocities relative to an observer.
Yes you were, you just don't realise it because you don't understand physics. Here, let me help. Velocity cannot be measured except relative to some observer, so you are really saying:

If both objects are  moving up relative to some observer, the relative velocities between them will be different than if they are moving in opposite directions relative to some observer.
The only difference between these two scenarios is which observer you choose. There is no difference in the physics, so this claim is incorrect.

Of course, none of this gets us any closer to answering the question If two objects are 1000m apart and one moves up 533m in 15s and the other moves up 1103m in 15s, how far apart are they at the end of the 15s.?  That's a simple 3rd grade level word problem. Let me know when you've worked it out.
You are just throwing meaningless numbers around. Can you actually describe the model you are using, or did you just throw some numbers into a random website and hope for the best?

To calculate the relative velocities between two objects that are moving in the same direction, you add their individual velocities.  To calculate the relative velocities between two objects that are moving in opposite directions, you subtract their individual velocities.
This is also incorrect. You subtract their velocities, which are vector quantities, in both cases. Do you understand vector arithmetic?

3
Flat Earth Theory / Re: Why do objects fall at dofferent speeds?
« on: July 29, 2021, 11:44:22 PM »
It does make a difference because the relative velocities of two moving objects is different if they are moving in opposite directions or the same direction, or if one is moving and the other is not.
No, again, you are missing the most basic principle of relativity, that velocity is relative. In any motion involving two objects with different velocities in one dimension, you can choose an observer such that one object is stationary, or they are moving in the same direction, or in different directions. The choice of observer will not affect the fall time (unless you choose an observer moving fast enough that time dilation becomes significant), but some choices can make calculations easier than others. This has been accepted physics since Newton's Philosophiæ Naturalis Principia Mathematica was published in 1687, which leads me to suspect that you have never taken a physics course.

If you get different results depending on whether you model the Earth as accelerating up or an object as being pulled down to Earth, your mathematics is wrong.

4
Flat Earth Theory / Re: Why do objects fall at dofferent speeds?
« on: July 29, 2021, 02:29:32 PM »
In FE, the atmosphere is always going to provide a motive force upwards, rather than a resistance.
Those are the same thing. In RET, to a free-falling observer with the same initial velocity as the falling object, the atmosphere provides an upward motive force. In FET, taking a non-inertial observer accelerating with the Earth, the force is resistive. This is like arguing about whether the object is undergoing acceleration or deceleration — it makes no difference to the physics, you can use whichever description suits your frame of reference.

5
Flat Earth Theory / Re: Why do objects fall at dofferent speeds?
« on: July 29, 2021, 07:47:09 AM »
Quote
You seem to be having difficulty with the most basic principle of relativity, that velocity is relative to the observer. There is no difference between resistance and thrust in this context, it is just a convention of nomenclature that depends on whether you choose a frame of reference in which the skydiver is stationary or moving down. It does not depend on the shape of the Earth or whether the Earth is accelerating up.
That makes no sense.  True that velocity is relative to the observer but the only observers we are concerned with are the diver and anybody on the ground.  Why would the diver ever record a different fall time than someone on the ground?
I didn't say they would. Try reading my post again.

6
Flat Earth Theory / Re: Why do objects fall at dofferent speeds?
« on: July 28, 2021, 10:58:04 AM »
In other words, if there is no force pulling him down, air flow from the bottom up would only propel the skydiver up.  The force coming up from the ground and catching the parachute isn't "resistance", its thrust.
You seem to be having difficulty with the most basic principle of relativity, that velocity is relative to the observer. There is no difference between resistance and thrust in this context, it is just a convention of nomenclature that depends on whether you choose a frame of reference in which the skydiver is stationary or moving down. It does not depend on the shape of the Earth or whether the Earth is accelerating up.

7
Bosnian Serb politicians have said they will boycott the country's institutions in protest at the United Nations high representative's decision to ban genocide denial.

This is in reference to the Srebrenica massacre during the Bosnian War, in which over 8000 Bosniak Muslims were murdered. While I don't condone genocide denial, I do think that those with a different view of what happened have the right to express their opinions. Every healthy democracy must protect the right to free expression.

Bosnia and Herzegovina has submitted an application to join the European Union, and this issue will undoubtedly present a hurdle for their application. Let's hope they get back on the right track.

8
Philosophy, Religion & Society / Re: Coronavirus Vaccine and You
« on: July 27, 2021, 08:10:59 PM »
They've had 922 deaths. We've had over 129,000.
Your witness...
In January and February — just before vaccines started to become generally available, but after the appearance of some more infectious strains — the northern hemiplane had our flu season while Australia was in the middle of summer. There are multiple factors at work here, and while I do agree that lockdowns likely played a big part in reducing the impact, there's more to it than just a difference in lockdown policy.

10
Philosophy, Religion & Society / Re: Coronavirus Vaccine and You
« on: July 27, 2021, 12:42:00 PM »
The vaccines are Highly Effective™


According to the Royal Navy,
each ship will have a total crew of 679, only increasing to the full complement of 1,600 when the air elements are embarked.
The best vaccines have an effectiveness of around 90%. 90% of a crew of 1600 is 1440, leaving 160 people who would be expected to get sick. As it turns out, 100 is less than 160.

11
Suggestions & Concerns / Re: embed tweets
« on: July 27, 2021, 12:23:57 PM »
I do think this seems like a reasonable suggestion, and probably not terribly difficult to implement. I don't know when I'll have time to look at it, but I will when I get a chance.

12
Philosophy, Religion & Society / Re: Coronavirus Vaccine and You
« on: July 24, 2021, 08:16:14 PM »
I’d suggest that any policy here should surely be based on how much of a risk you actually are to public health.
Agreed.

My gut feeling is that stopping non vaccinated people from going to venues is out of proportion to the actual risk although that is hard to quantify.
That's a position I can respect, but only if you are consistent and also say that lockdown was always an excessive measure. If a vaccine-resistant strain develops, and if lockdown is a justifiable measure against a strain of this virus for which we have no vaccine, then allowing unvaccinated people to spread the virus is only likely to bring another year of lockdown while new vaccines are developed.

So, either there is no significant risk involved and we won't need another lockdown to deal with a vaccine-resistant strain — in which case we shouldn't have had the lockdown we already had — or we should be doing all we can to avoid further lockdowns with incentives to be vaccinated.

13
Philosophy, Religion & Society / Re: Coronavirus Vaccine and You
« on: July 24, 2021, 06:03:31 PM »
The argument is that they could still catch it and spread it to more vulnerable people but:

1) So can vaccinated people
This point keeps being raised, and the best thing that can be said about it is that it is technically true. Depending on the specific vaccine, choosing not to be vaccinated increases your chances of developing symptoms by a factor of between 3 and 10. Even if you do get infected after being vaccinated, you are likely to experience a shorter time to recovery, which reduces the number of opportunities you have to spread the virus.

2) If almost all the vulnerable people have been vaccinated then they shouldn’t be at risk anyway.
Unless a new vaccine-resistant strain develops as a result of widespread recklessness around the spread of the virus, as we have already discussed in another thread.

But I do think there’s a principle here that this sort of coercion to almost force people to have the vaccine if they want to get on with their normal lives is morally questionable.
This is sort of like saying that it's morally questionable to require people with HIV to inform potential sexual partners of their condition. It is, after all, a restriction on their ability to lead a normal sex life. If you are a risk to public health and you choose not to mitigate that risk to others, you get to deal with the consequences.

16
The European Parliament has passed a law allowing e-mail and messaging service providers to automatically scan all messages for suspicious content and report matches to police, under the guise of protecting children. The linked article provides a good, if somewhat biased, overview.

This is not as invasive as surveillance legislation in some other parts of the world. For instance, it does not require service providers to conduct surveillance, it only permits it, which enables users to choose providers that respect their privacy. The full text of the legislation also provides limitations on the extent of such surveillance, restricting it only to detection of child abuse. It also explicitly excludes breaking of end-to-end encryption from its remit.

But Patrick Breyer, the author of the article linked in the first paragraph, makes an argument that this surveillance will not actually help combat child abuse.

Indiscriminate searches will not protect children and even endanger them by exposing their private photos to unknown persons, and by criminalising children themselves. Already overburdened investigators are kept busy with having to sort out thousands of criminally irrelevant messages. The victims of such a terrible crime as child sexual abuse deserve measures that prevent abuse in the first place. The right approach would be, for example, to intensify undercover investigations into child porn rings and reduce of the years-long processing backlogs in searches and evaluations of seized data.

Further (see the linked article), he is planning legal action in the context of a European Court of Justice ruling on the subject.

You can see a list of which MEPs voted which way on the legislation here, under the section Use of technologies for the processing of data for the purpose of combating online child sexual abuse (temporary derogation from Directive 2002/58/EC). This may be helpful in determining whom to vote for in 2024, whichever way you lean on this issue.

17
Philosophy, Religion & Society / Re: Coronavirus Vaccine and You
« on: July 22, 2021, 07:31:06 PM »
Regardless, the decision was made to allow emergency use. I find citing international agreements to be a bit disingenuous, since the US flagrantly gives no fucks about them in a number of areas, so clearly an adherence to this particular one is merely politically motivated.
The Nuremberg Code isn't even an international agreement. It's a set of guidelines some people wrote down 70 years ago, and which has inspired various treaties and laws, but by itself it has no power, legal or otherwise, anywhere in the world.

I was trying to ignore this obviously terrible troll, but apparently other people have decided to engage, so I've said my piece now.

18
A third of submissions on the first stage of consultation are negative, although this article doesn't go into a great deal of detail about why. It is interesting that some councillors are talking about the ring road, which seems to have little to do with this project. The ring road would relieve the existing N6, which is not impacted at all by these bus priority works.

19
Philosophy, Religion & Society / Re: Coronavirus Vaccine and You
« on: July 20, 2021, 11:17:13 AM »
The Netherlands is leading the world in innovative ideas again. You can now go to Haarlem for a jab and a blind date while you wait to be allowed to leave the testing centre. The idea is to help single people for whom the lockdown has been particularly lonely.

20
Philosophy, Religion & Society / Re: Civil unrest in South Africa
« on: July 19, 2021, 09:22:07 PM »
No news of this in the UK.
There is. Granted, I had to click through to World and then Africa to find it, but it's there.

Pages: [1] 2 3 ... 107  Next >