studiot

73% of 50 is exactly 36.5. Where you count the maybes as yes or no where does the half a response come from? Hence the comments in the other posts.

Was the moisturising lotion London Pride or Fullers Winter? Both these also come in half pints for those who get half cut and make half _ssed statements.

I think that the difficulty arises at least in part becuse you are thinking that manipulation in John's post#2 and in your book implies multiplication. It does not. It implies composition of functions. The output of composition is another function. I am going to assume you understand what a function is, please ask if you are unsure as this is an important concept. In your notation y is a function of x. We can obtain a second function properly called "the derived function" by following certain rules, known as differentiation. The derived function is often abbreviated to the derivative. However you should realise it is a function in its own right. Moreover it is a function of x (not y). So we can attempt to obtain a derived function from it. I say attempt because not all derived functions are suitable to provide a derived function. If successful, the second derived function will also be a function of x. A pity you are not being taught by my old A level maths teacher. He was the best teacher I have ever had in any subject. He used to insist that when we performed differentiation we made clear the variable concerned by writing "differentiate with respect to x" or d.w.r.x for short. You always got a mark for that even if you fluffed the algebra of the differentiation itself. This practice is good in more advanced work since it helps keep track of things. To recap, differentiation operates on functions and its output is a function. Consequenctly we can repeat this operation multiple times, following the rules for composition of functions each time.

Enthalpy, we seem to have difficulty communicating to an extent that you have attributed several statements to me that I did not make and then proceeded to argue against them. So let us try discussing one statement at a time. In your post#15 you seem to be suggesting that the fact that the speed of sound in steel is some 15 to 20 times that in air is irrelevant. In truth this fact is absolutely vital to the nature and distribution of the sound waves generated by the bell, both in the air inside and outside the bell. It should further be noted that the the bell itself is a single oscillator and not undergoing wave motion.

It's a history of molecules, valency and molecular bonding from earliest times, by a London professor of and practising industrial chemist (mainly pharmacy if I remember correctly). Yes it leads up to the Kekule inspiriation of ring molecules, but discusses all the necessary precursor work, including the blind alleys. There are many more amusing tales, including failure to know or distinguish story of cis and trans isomers that led to mass poisoning. It also includes plates of original documents. I found the copy I read in my local library. In the UK we have something called interlibrary loans. The library should be able to obtain any book in print for a nominal fee. http://www.amazon.co.uk/s/ref=nb_sb_noss?url=search-alias%3Dstripbooks&field-keywords=chasing%20the%20molecule%20buckingham

These questions are set at end of school / beginning of university level. As such you will have had substantial grounding in physical chemistry before they were issued. Have you read the homework help rules? http://www.scienceforums.net/topic/75772-read-this-before-posting-in-homework-help/ Start with part 1 which is the simplest. What rules or laws do you know that might be pertinent?

A really good account is given in the book Chasing the Molecule by Julian Buckingham (Sutton Publishing 2004)

I beg to differ. The sketch by light meow is strictly bias modulation, not amplitude modulation, which produces a different curve. It is what you would achieve if you set a function generator to the higher frequency in lightmeow's sketch and manipulated the output bias control in accord with the lower frequency waveform. True amplitude modulation appears about the zero line as here https://www.google.co.uk/search?tbm=isch&hl=en-GB&source=hp&biw=&bih=&q=amplitude+modulation&gbv=2&oq=amplitude+modulation&gs_l=img.1.0.0l10.812.4469.0.6969.20.14.0.6.6.1.344.2079.0j8j2j1.11.0....0...1ac.1.34.img..4.16.1921.8jkP2z__saQ Mathematically if the main wave is A * sinw1t Where A is a constant called the amplitude we get amplitude modulation if we multiply A by a second sin frequency thus B * sinw2 t* A * sinw1t What lightmeow has drawn is what happens if we add a second frequency sin wave to the original waveform. A * sinw1t + B * sinw2t

Why can't it's state, position and speed be determined? I define it to be 1kg mass and travelling at 100mph along the y axis. I then ask to calculate the force required to accelerate it to 200mph in 10 seconds. If you really don't like my example, then try this one where the object is not the only thing inthe universe. Place a point mass, mass m, ( a perfectly respectable object in theoretical mechanics) Place it at the exact centre of a uniform spherical shell of total mass M and diameter 1000 metres. What force is required to displace this mass from the centre and accelerate it in any direction at 1m/s2?

I've made no assumptions. I've simply applied the theory based on the mathematical principle that if an equation holds for all x then it must hold for any particular value I choose.

I doubt that anyone would award me a knighthood, but thanks. The short answer is yes but I will have to give it some thought, before a fuller reply. Obviously the modulus controls the strength of the restoring force that generates the oscillation and thus affects the amplitude. But there is also a big difference in density between water and air and it is the density variation that distorts voices in other gasses such as helium by affecting the speed of sound.

Swansont's answer give a clue as to why a wave travelling in one direction can meet another wave travelling in a different direction, the two waves have a conflab at their meeting point, and then pass through each other each going their separate ways as if they had never encountered each other. This is entirely different behaviour from that of solid particles. Energy does not preserve direction, momentum does.

I'm sorry, I no longer have the sensors capable of submersion. I last studied and used underwater acoustic profiling and positioning systems in the late 1970s/ early 1980s. Here is the meter I was using for this thread. It is a very versatile multimeter that I keep in the toolbox.

So what have I said that was controversial? ***************************************************************************************************************************************************** Function, I don't know if you are still following this thread but here is a simple experimental analogy to what is happening. Take an ordinary bicycle pump. Remove the handle, complete with shaft and piston. Crank the shaft and piston backwards and forwards in the same motion that it would follow inside the pump sleeve. Do you feel significant air resistance? Now put the inner assembly back inside the pump sleeve and repeat the action. What do you notice? You should notice that there is a significant fixed resistance due to sidewall friction. But there is also increasing resistance the more you compress the air inside. This is because the air inside the pump is confined, whereas the free air in the atmosphere is not. Just as I said in post#4 about the difference between the air inside and outside the bell. This analogy is not exact but follows the same principles. The pump is rather more dramatic because the air in the bell is loosly confined whereas the air in the pump is tightly confined. You can perform further experiment, this time on waves and resonance, with your pump. Try to pump backwards and forwards at different rates and observe what happens.

If there was only one mass, m1 then Newton's second law Finertial = m1a Still holds. Why do you wish to deny it? However Newton's law of gravity woul still hold, but Fgravitational = km1m2/r2 so Fgravitational = 0 since m2 = 0 There is nothing inconsistent here to be a matter of opinion about.. If the equations said something different then I would report that.

No Consider a universe where there is a single particle with mass. There is still inertia, measured by Newton's second law, but there is no gravity.

Perhaps someone typed this expression into the nav computer of the missing plane?

So did I, but when you type it into Excel or a calculator, directly as written in post1 you obtain a result of 36 (not an error and not 1)

Don't forget that the EM equations (sorry I have to mention that word) have axes that plot the Electric and Magnetic field amplitudes (intensities or strengths) against a spatial axis. So the EM wave is a wiggle of real observable physical quantities. The wave function psi is a complex variable that has real and imaginary parts. It is not a directly measurable physical quantity, but a derived one that 'oscillates' in its own peculiar space.

But photons are the modern version of the corpuscular theory, not the wave theory. Let's not mix them please.

This is a nice theory, but is against the experimental evidence that is gained in the secondary school experiment to plot cooling curves (temperature - time graphs). Unless you have enormous quantities, for a pure substance the temperature remains constant at the melting point temperature until the substance is either melted or solidified. For a mixture the plateau is still present but is no longer parallel to the time axis ie is tilted. This is the basis for significantly used industrial chemical analysis and quality control techniques.

I have no idea what this refers to. Now we are getting somewhere. Thank you. I haven't called the soundwave outside the bell a standing wave, nor do I want to. For the simple reason it cannot be one. The outside surface of the bell produces a travelling wave that moves away from the bell, spreading out in all directions into function's zone D. Since this is indefinite free space (the experimental results are the same in a big field) there is nothing to cause a standing wave. I don't recall saying this was a plane wave, although assuming this simplifies the theory. Now I agree that there are nodes and antinodes in the air inside the bell (functions zone C). Therefore there are standing waves inside the bell. You have stated that these standing waves interfere with something. Can you explain how standing waves interfere, since they are standing? Travelling waves do indeed interfere with other travelling waves and those diffracting round the bottom of the bell from zone D into zone A will do just this. I'm sorry, run this past me agian. The metal is pushing the air, yet you say its speed exceeds that of the air. Ergo the air molecules must pass through the walls of the bell for this to happen.

When light is regarded as an electromagnetic wave it creates its own field. It is not a disturbance in someone elses' field. This is how it can propagate through otherwise empty space. In fact it is more complicated because it creates two fields. An electric one and a magnetic one. The electric field is not constant but waxes and wanes in a cyclic manner. Any changing electric field generates a magnetic field at right angles to itself. This magnetic field changes cyclically because the electric field changes cyclically. In turn, a changing magnetic field generates an electric field at right angles to itself. This electric field changes cyclically because the magnetic field changes cyclically. So the electric field generates the magnetic field, which generates an electric field which generates a magnetic field............. and so the wave progresses with energy being swopped back and fore between electric and magnetic as it is passed down the line. Here are lots of pictures showing this. https://www.google.co.uk/search?tbm=isch&hl=en-GB&source=hp&biw=&bih=&q=electromagnetic+waves&gbv=2&oq=elctromagn&gs_l=img.1.2.0i10l10.2390.4297.0.8812.10.10.0.0.0.0.172.1173.0j10.10.0....0...1ac.1.34.img..0.10.1173.nrwAKu8N_fU

It is a conspiracy to hide the fact that computers are thick. So they have their geek henchmen create obfuscation since they can only write on one line. I expect you were taught the proper way to say what you mean so [math]answer = \frac{{36}}{6}x6[/math] If you mean you owe me 36 and [math]answer = \frac{{36}}{{6x6}}[/math] If I owe you 1 Note that Excel and My TI calculator both render the original expression as 36.

Since we are discussing a photon travelling along a line, with no other influences, the first one is more appropriate, but there are no wiggles the probability density function is just a bump that moves along with time. The bump represents the most probable position of the photon at any instant. Wiggles occur when the photon is moving in some potential field (eg gravity since it is not charged), and there are constraints or boundary conditions such as the edge of a block of glass. For simple QM the bump dies away to infinity in both directions, but for relativistic QM the influence can only reach a certain distance ahead of the photon given by the peak of the bump +ct and the forward tail must zero there.