studiot

No, that was not the question posed. I stated that as a fact, with some backing reasoning. Given that statement as true I posed a question concerning the effect of that on movement of physical bodies. This question has nothing to do directly with special relativity. Your grid presentations are interesting though, as I have not thought in those diagonal terms. Thank you. However your (1+1) or (x, t) grid does beg the question Where would the the second observer be travelling? Since there is only one x axis and it is already occupied by michael and myself, how would she get past?

So how does that affect my comment?

Just noticed this, Do you mean Jersey, America or Jersey, Europe? Could it have been residue from a furnace? In your yard? Builders used to import clinker as aggregate under slabs. How much of the stuff is there?

Thank you, Jon, I had not heard of the specious present, but it is not what I meant. There has been some discussion of 'objects' moving (or being moved) in space by changing their x (and y and z) coordinates. There is no physical object that I know of that can be attributed to a single x or y or z coordinate ie no physical object has zero length, but occupies a connected segment of space. For instance when I move my 18" screen across the desk I move one side and the other and everything in between. I was seeking a corresponding statement in time for "movement" in time.

Do you live in a volcanic or formerly volcanic area? Could well be pyroclastic volcanic tuff. https://www.google.co.uk/search?hl=en-GB&source=hp&q=volcanic+tuff&gbv=2&oq=volcanic+tuff&gs_l=heirloom-hp.1.0.0l10.1141.5797.0.6672.13.13.0.0.0.0.188.1342.1j10.11.0....0...1ac.1.34.heirloom-hp..2.11.1342._QPfxH-joyM

I note that no Time Lord here has attempted to answer my post#59 Ask The Doctor.

Interesting iterative approach, Mondie. Looks promising.

This is where you need to clearly distinguish between the predictions of QM and classical electrodynamic wave theory (EWT). It is classical EWT that predicts the electromagnetic emission from accelerating charged particles. As such there is no quantisation, the waves are freely emitted. E and H fields at are generated at right angles to each other such that Where E and H are both proportional to the acceleration (a) and the charge (e) and inversely proportional to the distance from the charge ® [math]E,H \propto \frac{{ae\sin (\varphi )}}{r}[/math] phi is the angle made between the direction r is measured in and the direction of acceleration. According to this model, the electric and magnetic fields are always perpendicular to the direction of propagation and move with velocity c. Further because of the sine term they vary in intensity from zero in the direction of propagation to a maximum at right angles to it. I stress again there is not quantisation of these fields. The above is OK for charge speeds small compared to c but needs to be modified for speeds a significant fraction of c. This leads to an apparent energy and mass gain and quantisation effects. You might also find the following non mathematical explanation as to why a single accelerating charge should classically radiate EM waves. Consider a single charged particle travelling between A and B. The faster it goes the greater the steady current it is equivalent to. So if it is accelerating then that current is not steady but increasing. The magnetic induction is proportional to the rate of change of current. So as the particle accelerates, the equivalent current increases, which in turn causes a changing magnetic field. A changing magnetic field gives rise to a (changing) electric field. A changing electric field gives rise to a changing magnetic field. And so the wave is born.

Well your answer is correct, I didn't wade through your maths yet. Well done.

No, No, a thousand times No. Torque is not a force. Torque is an entirely separate effect. Mostly it is the result of a force, but there are other agents that can apply torque as in a Wankel engine. When considered in conjunction with a force, torque is the product of the magnitude of that force and a distance, called the lever arm. This is more difficult than and often confused with work = Force x Distance. A simple way to distinguish is that no (zero) work is done at distances measured at right angles to the line of action of the force. Work is force times distance measured in the direction of that line of action. (You have discussed this in other threads) Torque, on the other hand, is Force times distance measured at right angles to the line of action. We know (I have just said) this the work calculated this way is zero so torque is not work either. That is enough for now.

You draw a diagram to help yourself, not me. So just so long as you draw them. It is useful, but not esential to post a diagram with the question. So you could use paper. They could be not pretty, as mine are not.

Yes the extra distance walked is 2y. I'm sorry I saw this quickly and thought you had 2 equations in x and y I didn't realise that the second was just 120 times the first. So you have one equation Time driving plus time walking = total travel time. On the second occasion this equation still holds, but the times are different. They are different because he spends more time walking than before and less time driving. We know he walks three times as far so, as you said, the extra distance walked is 2y. This extra distance he walks is distance he does not drive so the distance he does drive is (x-2y) I will keep repeating this to you. Draw a diagram it is easy to see then. You should now be able to form your second equation in x and y.

Rest assured, many misunderstand torque. I am not even sure if torque is the appropriate quantity for what you want, which is why I asked Just ask your question in ordinary words and don't try to use technical terms. Allow others to introduce and explain technical terms and see how they use them. And, of course, ask for an explanation if they use a term you don't know. But don't guess.

Where does this come from? imatfaal has already suggested how to get your third equation (you don't need 4) So in each case distance walked plus distance driven = distance walked plus distance driven = x + y So if you introduce a new variable, say z for distance driven the second time x + y = z + 3y You now have 3 equations and 3 unknowns.

Well in part (1) you have two unknowns, x and y and two equations so you can calculate them. I think you said he walks y km. In part (2) your wrote down that he walks 3y km (look carefully at the words)

Some may have seen this before, but I thought it was a good one.

But objects in space, including that famous picture on the wall and yourself, do not just exist at spatial coordinates (x,y,z), which is a mathematical 'point'. Objects occupy a region of space, containing many such points. If you say that time is similar what region is occupied in the time axis?

It's not clear in Sensei's picture but inside the bottle there are two thin strips (or one strip nearly torn into two) of aluminium foil. They flap apart like a bird's wing when supplied with charge and fall back together when the charge is drained.

This is not quite right. as imatfaal said.

Not really. Torque is a three dimensional effect. Please ask what you really want to know about masses in circular motion.

Surely there is no such thing as a 'sustained' fusion reaction? Two nuclei collide and fuse, if the conditions are favourable. And that's it, game over. Mig, with respect, I think you could rephrase to what you actually mean.

You need to understand what 'torque' is before you can understand the answer. The answer is that the torque vector is directed at right angles to the plane of motion so it it lies in none of the directions you mention, which are all in the plane of motion.

Not necessarily. Operation by the operator i is equivalent to a rotation by pi/2. So i operating on anything will produce an orthogonal axis. Just as x,y,z and ct are orthogonal to each other, cit is orthogonal to all of them.

You need to do the back substitution after the calculation to return from 'imaginary time' it to our time t. see http://en.wikipedia.org/wiki/Wick_rotation and also http://en.wikipedia.org/wiki/Imaginary_time

The Ancient Egyptians has wells. What did they use to haul water out in? And where in the English Language has anyone ever written that they hauled water out of a well in a boat?