Bremsstrahlung: Acceleration / Deceleration?

[HydroDave63]

Texts can be incorrect. ASk a physicist they'll tell you there's no such thing. Anytime you are changing a component on the vector you are changing the vector itself. There's no such thing as deceleration.

Mike

the net effect of all the vector changes is a lower energy product at the end. Kinda like thermalizing a neutron. Are there neutrons that accelerate to relativistic speed by colliding with hydrogen??? Is it a crime to say it decelerates, which communicates the correct concept of reducing the energy by the change of vector etc, or simply that it's snob value for not knowing what exact term physicists use while clinking rings at the secret science tree house Lodge?

[rlbinc]

It may sound like legalese, but deceleration is simply a negative vector acceleration. (Deceleration is a rate of velocity change in the opposite direction - a positive value with an opposite vector)

A car is decelerating at 3 ft/ sec squared heading west is accelerating 3 ft/ sec squared east. It just hasn't stopped and changed direction yet. In this case Kinetic Energy is being dissipated as Thermal Energy (heat) in either the brake disks, or reverse spinning tires.

Likewise, our charged particle sheds Kinetic Energy by releasing Brehmstrahlung. 

[SloGlo]

I do think it is confusing and unfair on tests to use one and then the other, so the test needs to reflect the MOST (not always black and white) correct version and the study material needs to teach the same terminology as the test.

unfortunately, math (hence physics) is black and white.  there is no "most correct" term, simply the one that is correct.  ifen yinz lose points because you use the wrong term, it's no worse than if you lose points for using the wrong number.  use the correct number, get the problem write.  right down the correct word 'n get the problem solved.  dun deel.

[hamsamich]

sorry, not that simple. terminology is not math.  the english language as well as most languages, except dead ones, will and are at this very moment living and breathing (changing).  deceleration may be accepted by some people and not others.  even if you surveyed a hundred or so math proffesors and textbooks today and most of them agree, tommorrow is a different story. 2 + 2 will always equal 4, but the definition of deceleration will never stay put.

[SloGlo]

hamsamich..... yeah, it is.  teminology describes the function.  science is not a democracy. it duzant matter what "most people" say or think.  proof is in the proof.  "most people" usta think the whirled was flat.  good thing they weren't listened to by those who were involved with the sciences, huh?  perhaps we should consider the opposite of decelleration to be procelleration, with the lack of pro or de to be simply celleration?

[hamsamich]

sorry, science doesn't work that way either! and terminology isn't the same as a proof.  science is probably even more dynamic than terminology.  i wish things would stay put sometimes or be as black and white as we want them to be but they never will be....sorry about that.  the "they" is us.  have a look at a dictionary sometime from the 50s and compare it to one today.  people used to say the same thing about the world being flat, but now we know it isn't.

[Halcyon Daze]

For my money, language is the use of words to convey ideas, so the word that gets the point accross to the most people is the "right" one. You have to target your audience though, so if you're talking to a bunch of people with white coats and big heads, use "acceleration." If you're talking to a cross section of people, use "deceleration."

[SloGlo]

check yer ancient greeks 'n yule find yer modern math formula 'n functions 'n stuff.  'n when i go to da 50s, i don't see da diff.  still ain't got no fusion, but da fission math ' phizziks hold up.  lotsa statistics work comes outa that era two.  watt terminology changed?  now, da werds cool, rad, bad, etc may have taken on new meanings, but have they lost da originals?  i due knot think sew.

[Evilpixie]

I agree with Renhack, the NEU should not test on things that they do not adequately cover.  I remember the last time I took that test there were some questions I had issues with for the same reason.  It's like they had someone who is good at explaining things write the study material and for writing the test they hired a hygenically challenged scientist who lacks social graces, communication skills, deodorant and has it out for anyone taking the test.

Of course, it's been awhile since I took the test. 

Hmm... acceleration is a physical property.  A variable in physics.  A vector quantity that describes the rate at which an object changes its velocity.

Then, there is acceleration.  In everyday English it's used to describe a state of increasing speed.  It's what most peops are accustomed to. 

Acceleration in physics is much more than increasing speed.  Any change in the velocity of an object results in an acceleration: increasing speed, decreasing speed, or changing direction. The terminology for it hasn't changed since Newton... (at least), in calculus acceleration is the derivative of velocity.

I bet they didn't have anything in that training guide that made the distinction, huh?  That's wrong and rather unfair.
 

[RDTroja]

From 'YourDictionary.com" following a list of other definitions for 'Accelerate' mostly meaning 'to increase speed:"

Physics: To change the velocity of.

The same dictionary gives no physics definition of 'Decelerate.'

Since we are talking physics here, maybe we should be speaking in terms of Physics definitions, n'est pas?

Several people have already pointed out that accelerate means to change vector velocity... it does not mean increase or decrease, merely change. Others have pointed out that most people understand accelerate means to go faster and decelerate means go slower. This is true in everyday use, but physics is not every day use. You can get 100,000,000 people to agree that 'bad' means 'good' but that does not make it so. 'Common usage' is for art (or conversation), not science.

Bremsstrahlung is caused by acceleration. Period. If you don't understand the terminology, you don't understand physics.

[Charles U Farley]

Y(Eo) = 1/Eo ∫ dE E*Nbr(Eo,E) = 13/16 k*Z*Eo

[cincinnatinuke]

From 'YourDictionary.com" following a list of other definitions for 'Accelerate' mostly meaning 'to increase speed:"

Physics: To change the velocity of.

The same dictionary gives no physics definition of 'Decelerate.'

Since we are talking physics here, maybe we should be speaking in terms of Physics definitions, n'est pas?

Several people have already pointed out that accelerate means to change vector velocity... it does not mean increase or decrease, merely change. Others have pointed out that most people understand accelerate means to go faster and decelerate means go slower. This is true in everyday use, but physics is not every day use. You can get 100,000,000 people to agree that 'bad' means 'good' but that does not make it so. 'Common usage' is for art (or conversation), not science.

Bremsstrahlung is caused by acceleration. Period. If you don't understand the terminology, you don't understand physics.

So when the Navy uses the term "Accelerate Your Life" in its commercials, perhaps they want you to think in the common usage/art/conversation term, but may well in fact mean decelerate.  Could help explain all the field days, time underway, and periods of lonliness.

[hamsamich]

concepts are not terminology and never will be, they are the only thing that are truly right or wrong.  you can talk all day of how only the "correct scientist" uses the "correct terminology", but in the end terminology is all man-made.  concepts were there before anybody thought to name them.  can't anybody see the difference?  the words acceleration and deceleration are merely man made markers for the same concept, and which ever marker scientists prefer has nothing to do with the correctness of a concept.  if 100,000,000 people think a word means something, it DOES mean it means something, that is WHY language is living and breathing.  words, however scientific, mean something only because the human mind recognizes it as a marker for a concept.

acceleration is the most accepted and "most correct" word choice, I recognize that, but in no way do you not understand the CONCEPT of acceleration if you chose to use the term deceleration.  that is a fairly absurd statement.

[RDTroja]

if 100,000,000 people think a word means something, it DOES mean it means something, that is WHY language is living and breathing.

Conversational language changes with the times and opinions of people and is 'living and breathing' if you chose to use those (also incorrect) terms... and that is fine even though it creates a lot of confusion for people that speak english (probably other languages as well.) If people decide that 'bad' is 'good' or "fo' shizzle" means anything at all that is unfortunate, but accepted.

Scientific language changes if we learn something new that causes us to change our understanding of the subject matter and then only by concensus of the scientists. This is science, not conversation or any other art form. Yes, a scientist will understand if someone uses the term 'decelerate' and they will also recognize that the speaker has a limited understanding of the concept.

[hamsamich]

saying "language changing is incorrect" is a pretty narrow view of things. it's a good thing many of the world's most important scientists (einstein, newton, many others) didn't look at things the same way, whether it be science or language, or we would still be falling off the edge of the world after a few hundred miles of travel.

I don't think it is unfortunate that language changes and is living and breathing, if that is what you meant.  many people look at science as an art form.  string theory is cutting edge today and how much of that has been proven?

professionalization, terminology, and a concept will always be 3 different things giving words meaning and importance, even scientific ones.  if you ask 100 top scientists i bet they will all have different answers for the meaning of acceleration, deceleration, and the difference between the two.  things aren't as cut in stone as you think they might be, or maybe want them to be.

[RDTroja]

I never said "language changing is incorrect" so if you want to use quotes, you could at least quote something that I did say. Einstein, Newton, et. al. did look at things from a scientific view and found new things that required new language and convincd the rest of the scientific world that they were right (or reasonably close enough) to accept the ADDITIONS to the language that were required to express the new ideas. Technicaly, they didn't change anything... they just found a way to explain how things work. The other scientists acceptance of the concepts is key to any scientific endeavor, including the language used to describe it. And even though I am not quite old enough to have witnessed it myself, I am pretty sure no one really fell off the earth before scientists changed its shape.

I do not think that changing language in general is unfortunate, but some changes are, fo' shizzle. Breeding ignorance into the English language is IMHO fairly tragic. But that is another topic. As for string theory and other cuttting edge concepts, they too may require some additions to the scientific dictionary, proven or not. They certainly introduce new concepts and change the way we look at old ones. But they will not require scientists to accept random changes to the way they describe their science because someone in their 15 minutes of fame changes the way pop culture speaks.

And, I will take that bet about the scientists. They will understand what deceleration means but very likely not use it in their next published work.

[Halcyon Daze]

ahhh, but do any of us know if 'deceleration' was added to the language, or was the concept of 'acceleration' expanded to encompass all changes in velocity?

[hamsamich]

Halcyon Daze, that is the kind of stuff I am talking about.  Good question.  we could probably go to the oxford english dictionary and check it out.

I don't know what you said then Troja, sorry.  Fo shizzle, hmmm, how about mesmerize instead, or say jingo?  There are plenty of examples of words that have come about in the last 400 years that were not there before.  I don't understand what you think is incorrect concerning your other post; you'll have to rephrase for me.

Do you really think deceleration has been around for 15 minutes?  I doubt it.  I know what you are saying, but deceleration has been around as long as acceleration probably.

Yes, most scientists will use acceleration.  I'm just saying that although not perfect, it is not 100% wrong either.  And just because someone uses the term deceleration doesn't mean they don't know what they are talking about.  I guess I just don't like gatekeeping (professionalization) type words and others that throw stones concerning word usage.  We all know what deceleration means, and saying it is completely incorrect and the people who use it aren't on par with the rest of us physics studs just seems like that type of thing to me.  There have been plenty of times in history when the guys using the big words got it wrong, and then hid behind esoteric words in ivory towers.  Think midwives in the late 19th century or phrenology.  Maybe the word "acceleration" isn't a good example of this, but people that come out and say "you just can't use deceleration because it is not right', well, this rubs me the wrong way.  Why isn't it right?  Get of the high horse and instead of saying "you don't know what you are talking about because you didn't use the right word", try, this MIGHT be why most scientists don't use that word, but technically you are correct.

Sorry, the attitude coming from a few posters concerning this pet peave of mine left a bad taste in my mouth

[RDTroja]

I am not sure which button got pushed or by whom, but this has gotten so far off of the track that it started on as to be an entirely different subject all together.

I could care less what words people use to talk to one another in daily conversation. I do have a lot of respect for the English language and personally don't like the direction that the changes are taking, but that is just one person's opinion. I disagree with the 'dumbing-down' (coming soon to a dictionary near you) of America as demonstrated in pop-culture, but there it is.

What is not opinion is that purely from a scientific view (and last time I checked Physics was a science) acceleration is used to describe a change in velocity -- positive or negative, depending on the relative view.  So, if one is to ask what causes Bremsstrahlung, the answer is acceleration. But only if you want the answer in scientific terms. And since our industry deals chiefly with science, that is the answer that makes the most sense. Call it whatever you want, but if you care about giving the most accurate answer, call it acceleration. And that is the problem today -- not enough people care about much. Just another opinion, of course.

[hamsamich]

I can dig it.  But I think this type of thing has always been associated with acceleration and deceleration; people get hung up on whether the word is correct instead of the meat of the issue.

[Evilpixie]

ahhh, but do any of us know if 'deceleration' was added to the language, or was the concept of 'acceleration' expanded to encompass all changes in velocity?

According to dictionary.com: 
accelerate originated around 1515-1525; de+(ac)celerate in 1895-1900

[SloGlo]

Get of the high horse and instead of saying "you don't know what you are talking about because you didn't use the right word", try, this MIGHT be why most scientists don't use that word, but technically you are correct.

Sorry, the attitude coming from a few posters concerning this pet peave of mine left a bad taste in my mouth

try using "negative dpm" sum time to describe a count rate < background 'n see watt consensus yule build wit yer listeners.

[bsdnuke]

Bremmstrahlung means braking radiation hence, slowing down.

[illegalsmile]

Bremmstrahlung means braking radiation hence, slowing down.

uhhhh, i think everyone here understands that the beta bug slows down. the point of contention is if slowing down constitutes deceleration or negative acceleration......semantics really.

[HAIRDUDE]

Here's what I get from it all:
Beta particles pass by at such an angle to any given nucleus and are "sling-shot" to a speed greater than the speed of light. This basically is the equivalent of putting the particle on 'crank'. When it is free of the "sling-shot zone" it begins to rapidly decelerate and gives off some of it's kinetic energy as 'the glow' due to its inability to loose enough energy throyugh deceleration alone. Then there is the part about the 'underpants gnomes' ... but I promised I wouldn't talk about that ... 

HAIRDUDE