Understanding electromagnetism

[Brain Man]

t+30 minutes.

Why am I not surprised.

if u want a challenge on basic physics ability then both parties need to agree terms and conditons first.

Why would you want a ‘rematch’. His failure is spectacular.

Rematch of what, there was never any kind of match agreed on to start with except twiglet talking down and then presuming farsight would be sitting on this thread to reply to him. Dont know about you, but i dive in and out of web sporadically on mobile phone, car laptop etc U are obviously just here to troll these threads. I notice you haven't made a contribution to the subject matter in quite a while and are purely focussed on trying to discredit the author and anybody who supports him.

But even if farsight stil couldnt work out this newtonian problem in that space of time, i am pretty sure he could at his own leisure. Its not that hard but its also a pretty dull example. I remember finding it quite tedious myself from school. You would need to give me strong motivation to get me try and do that today.

U get the idea we are back to hillwalkers and valley jumpers scenario. The hillwalkers are happy to focus on all the boring tedious stuff to high degrees of excellence, and see that is the only way to progress. Everybody has to be judged by their high standards. They have built walls of knowledge around them by which they can exclude anything new. We went into this previously.

[ChildInAZoo]

U get the idea we are back to hillwalkers and valley jumpers scenario. The hillwalkers are happy to focus on all the boring tedious stuff to high degrees of excellence, and see that is the only way to progress. Everybody has to be judged by their high standards. They have built walls of knowledge around them by which they can exclude anything new. We went into this previously.

But how can someone be thought to be doing physics when the stuff that they discuss they cannot understand?

[Farsight]

Rematch of what, there was never any kind of match agreed on to start with except twiglet talking down and then presuming farsight would be sitting on this thread to reply to him. Dont know about you, but i dive in and out of web sporadically on mobile phone, car laptop etc U are obviously just here to troll these threads. I notice you haven't made a contribution to the subject matter in quite a while and are purely focussed on trying to discredit the author and anybody who supports him.

It amazes me that these guys don't think anybody notices, Brain Man. If you have any psychology colleagues, I think this would make an interesting area of study. IMHO conviction seems to be in some way related to hypnotism, and it's very difficult to snap people out of it. Hence it is harder to crack a prejudice than an atom.

But even if farsight stil couldnt work out this newtonian problem in that space of time, i am pretty sure he could at his own leisure. Its not that hard but its also a pretty dull example. I remember finding it quite tedious myself from school. You would need to give me strong motivation to get me try and do that today.

It's a smokescreen diversion of last resort. I've played the game before, spending hours on a careful mathematical presentation, only to have my detractors say that's wrong! when it isn't, or you cribbed it! when I didn't. Or both. Or anything else, or they do a runner. It's futile to do anything other than force the focus on the evidence. But this isn't easy when they won't read the OP or enter into the discussion, and are only interested in trashing it. What disappoints me is that moderators don't seem to understand that when one trashes the thread, in the end, one trashes the forum.

Anyhow, I've explained energy and mass, let's see how Twiglet responds to that before I deliver the coup de grace.

[lpetrich]

OK, no problem. I'll start by explaining energy, then I'll explain mass. Then the rest.

Good, you can start by producing the general classical solution for projectile motion under gravity, without friction, of an object fired at a speed v, angle x to the horizontal, from a level surface. Assume g=10m/s^2. Having obtained the general solution, specify the angle which provides the greatest range, and justify your answer.

No, I've started by explaining energy. Here it is: Energy Explained. Now read it. Giving trivial equations for a ballistic trajectory is irrelevant to explaining why why c is a limit in special relativity.

Farsight, that is intended to test how well you understand simple Newtonian mechanics and using mathematics to make predictions.

I myself had no trouble with that problem - I used Mathematica to help work out the solution, and it took me only a few minutes.

[Farsight]

And after that there'll be another and another, Loren, one piece of schoolboy trivia after another. I've just given energy explained and mass explained, and I've previously given time explained. These comprise an analysis of the mathematical terms within E=mc². It's vital that we stay on topic to address this rather than enter into a string of crystal-spheres distractions that merely juggles the terms around and around. Now do read the OPs, and do excuse me because I must go.

[Brain Man]

t amazes me that these guys don't think anybody notices, Brain Man. If you have any psychology colleagues, I think this would make an interesting area of study. IMHO conviction seems to be in some way related to hypnotism, and it's very difficult to snap people out of it. Hence it is harder to crack a prejudice than an atom.

Believe it or not we are studying it. We actually use these insights to decide how to approach other scientists. i.e. We psychologically profile a scientist before interacting with them, and have preset methods as a guide. i.e. Certain universities enforce and condition standards of rigid conformity, such as cambridge, oxford, while others such as UCLA are more freewheeling, open minded and creative.

There are times when a communication is required to be sent to somebody in oxford or kings college we use brief clipped remote phrasing. Refer to authority, are very cautious about presenting a concept that might be too contraversial. While conversely if you interact with somebody from Spain or West america, you need to be really available. Call them personally be enthusiastic, open and forthright. The latter isnt a problem as we are creative and forthright anyway. We devised the method to deal with the former.

Of course we still test that there are exceptions. There are many vice versa and other examples in each category, but overall profiles help. They actually help the other scientist be at ease. Also If somebody is rigid and non creative its a waste of both our time to expect anything else.

It's a smokescreen diversion of last resort. I've played the game before, spending hours on a careful mathematical presentation, only to have my detractors say that's wrong! when it isn't, or you cribbed it! when I didn't. Or both. Or anything else, or they do a runner. It's futile to do anything other than force the focus on the evidence. But this isn't easy when they won't read the OP or enter into the discussion, and are only interested in trashing it. What disappoints me is that moderators don't seem to understand that when one trashes the thread, in the end, one trashes the forum.

yeh ive seen that one. They reason they accuse you of smoke and mirrors is because its a projection of their own processes.

[JimC]

Farsight wrote:

But this isn't easy when they won't read the OP or enter into the discussion, and are only interested in trashing it. What disappoints me is that moderators don't seem to understand that when one trashes the thread, in the end, one trashes the forum.

I think it is clear that you don't understand the moderation ethos here, which may be quite different to other places. Moderation is done with a very light hand, and is mainly concerend with dealing with clear examples of personal attacks. We don't buy into arguments involving "he hasn't adressed the OP" or "this post is a tangent"

Also, you must understand that many posters are skeptical of your portrayal of central physics concepts, suspecting that you are only painting pictures, not grappling with the mathematical structures in any meaningful way. Therefore, demonstrating your ability to do a basic piece of mathematical modelling in physics may have done wonders for your credentials...

PS - Twiglet, I will do the ballistics thing soon, at least in providing the method to derive range and maximum height as a function of v and x. I will be limited by my modest ability to format stuff in a post in this forum...

[Xamonas Chegwé]

Farsight wrote:

But this isn't easy when they won't read the OP or enter into the discussion, and are only interested in trashing it. What disappoints me is that moderators don't seem to understand that when one trashes the thread, in the end, one trashes the forum.

I think it is clear that you don't understand the moderation ethos here, which may be quite different to other places. Moderation is done with a very light hand, and is mainly concerend with dealing with clear examples of personal attacks. We don't buy into arguments involving "he hasn't adressed the OP" or "this post is a tangent"

Also, you must understand that many posters are skeptical of your portrayal of central physics concepts, suspecting that you are only painting pictures, not grappling with the mathematical structures in any meaningful way. Therefore, demonstrating your ability to do a basic piece of mathematical modelling in physics may have done wonders for your credentials...

PS - Twiglet, I will do the ballistics thing soon, at least in providing the method to derive range and maximum height as a function of v and x. I will be limited by my modest ability to format stuff in a post in this forum...

Pen, paper, scanner?

[JimC]

Farsight wrote:

But this isn't easy when they won't read the OP or enter into the discussion, and are only interested in trashing it. What disappoints me is that moderators don't seem to understand that when one trashes the thread, in the end, one trashes the forum.

I think it is clear that you don't understand the moderation ethos here, which may be quite different to other places. Moderation is done with a very light hand, and is mainly concerend with dealing with clear examples of personal attacks. We don't buy into arguments involving "he hasn't adressed the OP" or "this post is a tangent"

Also, you must understand that many posters are skeptical of your portrayal of central physics concepts, suspecting that you are only painting pictures, not grappling with the mathematical structures in any meaningful way. Therefore, demonstrating your ability to do a basic piece of mathematical modelling in physics may have done wonders for your credentials...

PS - Twiglet, I will do the ballistics thing soon, at least in providing the method to derive range and maximum height as a function of v and x. I will be limited by my modest ability to format stuff in a post in this forum...

Pen, paper, scanner?

A possibility...

[lpetrich]

I will concede that I'm a bit creative in ASCII math typesetting.

Like my recent posting of the Navier-Stokes equations.

I'm holding off on posting my solution, because I don't want to spoil anything.

[Twiglet]

It's a smokescreen diversion of last resort. I've played the game before, spending hours on a careful mathematical presentation, only to have my detractors say that's wrong! when it isn't, or you cribbed it! when I didn't. Or both. Or anything else, or they do a runner. It's futile to do anything other than force the focus on the evidence. But this isn't easy when they won't read the OP or enter into the discussion, and are only interested in trashing it. mass, let's see how Twiglet responds to that before I deliver the coup de grace.

I picked the question I did for several reasons:

1) The solution requires a couple of easily written assumptions to be stated.
2) The entire solution is keyboard friendly, using x as an angle and v for velocity means no need for the greek alphabet
3) The solution (bar one small part) is entirely algebraic
4) The problem is set at a level where examiners could easily agree if the solution has been arrived at correctly
5) The time it would take anyone competent with the maths and physics to solve the problem is quite literally the time it takes to write it down. I could write the solution in less time than it has taken to draft this post.
6) A more complex problem would lead most of the readers of this thread unsure of whether you had answered it correctly. I wanted a problem where your failure or success would be glaring and apparant to a wide number of readers.

Also a cribbed solution would probably be needlessly overcomplicated, and most university level solutions would use "angle theta" and vectors, whereas this problem can easily be solved with scalars, algebraicly. The solution can be formulated in no more than 7-8 lines of text.

I would have been less sceptical of you if you had taken 3-5 minutes to answer after my original post. But even if you had answered it, it would only establish your ability to solve one Newtonian physics A level problem. A level of ability I am not at all convinced you possess.

If your shoes farsight, if I had been able to answer the problem easily off the top of my head, I'd have done so in a few lines and then gone on to complain about it, because that would have been by far the most effective way to make my request look a bit silly, and at least demonstrate that you know as much as a 16 year old taking an A level. As it stands,I just feel validated in the belief that you can't even solve a problem within the reach of a 16 year old child studying physics.

[JimC]

OK, here we are, following XC's suggestion, some scans of my handwriting:

[Twiglet]

Rock & Roll Jim,

Oddly I was producing the solution at the same time. Here's mine:

Solution to Problem.

From Newtons equations of motion;
s=ut+1/2at^2

Resolve vertically, horizontally

Horizontally

s=v Cosx

Vertically, g=-10 therefore

s=vSinx t -5t^2
on the ground, s=0 but t doesn't, so time of flight, t is 0.2(vSinx)

Substitute back into the horizontal to find distance travelled
s=0.2 V^2 SinxCosx

__________

Identity: sinX cosY = (1/2) [ sin (X + Y) + sin (X - Y) ]
when x=y this reduces to:
1/2 Sin 2x

Therefore:

s=0.1v^2 Sin2x

When s is a maximum, ds/dx=0, hence Cos2x=0, hence 2x=90 degrees hence x=45 degrees.

[Twiglet]

NB Jim, one or other of us stuffed up on the trig ID - i believe you forgot that its 1/2 (sin 2x).

[JimC]

NB Jim, one or other of us stuffed up on the trig ID - i believe you forgot that its 1/2 (sin 2x).

Definitely my stuff-up - I did forget that it is 2sinxcosx = sin(2x)

Still, at least it did not affect the proof that 45 degrees delivers the maximum range...

This has stimulated me to make a thread sometime, somewhere with a number of upper secondary maths and physics problems, with maybe a little molarity problem from chem thrown in...

My expertise does not go beyond this level (apart from anuran biology, of course, and that somewhat ancient knowledge...)