Ask a physicist anything. (3)

[Wiccan_Child]

No disputes there, I was talking about in respects of Electrical/Comp Engineering though. However, you make a good point about thermodynamics. Heat transfer in circuitry is very important.

I was just wondering if Physics as a whole came into play in the electronics field. They are making me a take a LOT of physics and while I see the point when it comes to civil/aerospace/materials engineering I don't see the same hard-hitting difference in respects to electronics/circuitry. I have taken 2 Engineering Physics class and now I am about to head into the 200-level classes.

Not saying I don't like Physics. It is actually really fun and I enjoy the mathematical process.

Thanks Wiccan

No problem! I don't know what courses you're doing, so maybe they're making you do silly things like astronomy and radiology, which aren't that useful. I'm a theoretical physicist, but I had to do electronics! Don't they know not to put a theorist in an experimental laboratory?!

Though I was suitably impressed when I waved this LED thing back and forth and my name materialised in the air...

 

[shinbits]

why has it been determined that the universe curves, rather than expands forever? or is this a question for an astro-physicist?

 

[corvus_corax]

I (jokingly) asked a grade school teacher, with a masters degree in teaching, btw- "If E=mc2, then does c2m=E?"
Now, I was just joking around (we were in the break room at school).
But she got suddenly very serious and said "absolutely not"
So a discussion ensued, then an argument, where I was trying to explain to her that BOTH sides of the equation (no matter how you mash them up) have to come out the same
Examples I gave were "2+10=12 is the same as 12= 10+2", and (more specifically) "If Energy does equal mass times the speed of light squared, then the speed of light squared times mass must equal Energy" and then "Both sides of the equation have to balance out, even if you change the specific order".

Her rebuttal was, essentially, "You're not a teacher*, you haven't got the education"
There were some other arguments such as "You don't actually understand how that equation doesn't work with normal math" (not kidding, although she might be correct [insert shrug emoticon here]


So in regard to my jest regarding the math of E=mc2, was I correct, was she correct, were we both correct, or were we both completely off base?


Thanks for your input







*I'm not a teacher, I'm the kitchen manager in our school district

 

[Wiccan_Child]

I (jokingly) asked a grade school teacher, with a masters degree in teaching, btw- "If E=mc2, then does c2m=E?"
Now, I was just joking around (we were in the break room at school).
But she got suddenly very serious and said "absolutely not"
So a discussion ensued, then an argument, where I was trying to explain to her that BOTH sides of the equation (no matter how you mash them up) have to come out the same
Examples I gave were "2+10=12 is the same as 12= 10+2", and (more specifically) "If Energy does equal mass times the speed of light squared, then the speed of light squared times mass must equal Energy" and then "Both sides of the equation have to balance out, even if you change the specific order".

Her rebuttal was, essentially, "You're not a teacher*, you haven't got the education"
There were some other arguments such as "You don't actually understand how that equation doesn't work with normal math" (not kidding, although she might be correct [insert shrug emoticon here]


So in regard to my jest regarding the math of E=mc2, was I correct, was she correct, were we both correct, or were we both completely off base?


Thanks for your input

*I'm not a teacher, I'm the kitchen manager in our school district

Wow, no, yea, you were completely right! The symmetry of equality is one of its fundamental properties. E = mc[sup]2[/sup] is a perfectly ordinary equation, so c[sup]2[/sup]m = E. Crazy, crazy teacher... I can only hope she misheard you, thinking you said c[sup]2[/sup] = mE or something. Oy vey!

 

[Wiccan_Child]

why has it been determined that the universe curves, rather than expands forever? or is this a question for an astro-physicist?

As far as we can tell, the universe is flat. It depends on the distribution and mass of the universe. Mass curves spacetime one way, while the Big Bang curves it another. So which way the universe curves depends on which of these two things is stronger.

 

[TemperateSeaIsland]

I (jokingly) asked a grade school teacher, with a masters degree in teaching, btw- "If E=mc2, then does c2m=E?"
Now, I was just joking around (we were in the break room at school).
But she got suddenly very serious and said "absolutely not"
So a discussion ensued, then an argument, where I was trying to explain to her that BOTH sides of the equation (no matter how you mash them up) have to come out the same
Examples I gave were "2+10=12 is the same as 12= 10+2", and (more specifically) "If Energy does equal mass times the speed of light squared, then the speed of light squared times mass must equal Energy" and then "Both sides of the equation have to balance out, even if you change the specific order".

Her rebuttal was, essentially, "You're not a teacher*, you haven't got the education"
There were some other arguments such as "You don't actually understand how that equation doesn't work with normal math" (not kidding, although she might be correct [insert shrug emoticon here]


So in regard to my jest regarding the math of E=mc2, was I correct, was she correct, were we both correct, or were we both completely off base?


Thanks for your input







*I'm not a teacher, I'm the kitchen manager in our school district

If she hadn't misheard then she is a moron and shouldnt be teaching. What was her first degree in? I have a distinct feeling it was not in a science related subject.

EDIT - even if she misheard she's a moron for giving you the "You're not a teacher explanation"

 

[TemperateSeaIsland]

As far as we can tell, the universe is flat. It depends on the distribution and mass of the universe. Mass curves spacetime one way, while the Big Bang curves it another. So which way the universe curves depends on which of these two things is stronger.

To follow the previous question... What is space? I presume it is something if it curves.

 

[Wiccan_Child]

To follow the previous question... What is space? I presume it is something if it curves.

Space is a thing with depth, width, height, etc, in which other thing's position etc can be relatively measured. 'Over there' is five miles from my house because it is in a different location of space. Some things bend space, making it a bugger to pin down exactly where anything is.

It's also inextricably linked to time in mind-exploding ways.

How's that for an unsatisfactory answer

 

[AV1611VET]

Wow, no, yea, you were completely right! The symmetry of equality is one of its fundamental properties. E = mc[sup]2[/sup] is a perfectly ordinary equation, so c[sup]2[/sup]m = E.

Yup.

Another way to look at it:

If E=m(cc), then m(cc)=E.

 

[AV1611VET]

If she hadn't misheard then she is a moron and shouldnt be teaching. What was her first degree in? I have a distinct feeling it was not in a science related subject.

EDIT - even if she misheard she's a moron for giving you the "You're not a teacher explanation"

I had the best math teacher in college I ever had.

She had a masters in mathematics, and she was very knowledgeable.

On our opening day in Business Math, she said this:

"Don't be afraid of this class. The math you are going to use is very simple addition, subtraction, multiplication and division. However, don't take this class for granted, either. I've seen straight-A trigonometry and geometry students come in here thinking this class is going to be a piece of cake, only to see them barely make it through with Cs and Ds."

She even showed us how to tell instantly if 4 will go into a number evenly* -- no matter how large the number is; as well as how to tell instantly if any given year is a leap year or not.

* If 4 will go into the last two digits evenly, it will go into the whole number evenly, no matter how large it is.

 

[TemperateSeaIsland]

Yup.

Another way to look at it:

If E=m(cc), then m(cc)=E.

Heck just look at E = MC[sup]2[/sup] left to right and back again, it darn obvious and really worrying that a teacher doesnt know what a = sign means.

I had the best math teacher in college I ever had.

She had a masters in mathematics, and she was very knowledgeable.

On our opening day in Business Math, she said this:

"Don't be afraid of this class. The math you are going to use is very simple addition, subtraction, multiplication and division. However, don't take this class for granted, either. I've seen straight-A trigonometry and geometry students come in here thinking this class is going to be a piece of cake, only to see them barely make it through with Cs and Ds."

She even showed us how to tell instantly if 4 will go into a number evenly* -- no matter how large the number is; as well as how to tell instantly if any given year is a leap year or not.

* If 4 will go into the last two digits evenly, it will go into the whole number evenly, no matter how large it is.

Before I went to University I had a pretty good maths teacher too, learned a lot with him, which is lucky as I had to do a LOT more maths in Chemistry than I was expecting.

Another good trick is that you can tell if a number is divisable by 3 by adding all the digits in the number and if the sum is a number that is divisable by 3 then the original whole number is.

 

[AV1611VET]

Another good trick is that you can tell if a number is divisable by 3 by adding all the digits in the number and if the sum is a number that is divisable by 3 then the original whole number is.

Yup -- and if the sum is still a large number -- like a 4-digit number, you can add those too (and keep adding) until you hit a one digit number.

Ex: 845,997 = 42 = 6 = divisible by 3.

Casting out 9s is another neat trick.

Ex: 845,997 = 845,--7 = 24 = 6 = divisible by 3.

 

[Wiccan_Child]

I never learned much of those tricks; I just used a calculator

 

[AV1611VET]

I never learned much of those tricks; I just used a calculator

You guys count funny, though --

 

[TemperateSeaIsland]

I never learned much of those tricks; I just used a calculator

Young people these days

I like to do maths in my head or on paper/any surface available at the time so I try to use a calculator as little as possible.

 

[Wiccan_Child]

Young people these days

I like to do maths in my head or on paper/any surface available at the time so I try to use a calculator as little as possible.

Yea, I do the same. There are quite a few tricks I've picked up for doing it by hand (square roots and the like). I just don't like mental maths. My brain is too soggy from learning Russian to get used to mathematical tricks too!

 

[Chesterton]

You guys count funny, though --

They talk funny too. "Maths"?

 

[TemperateSeaIsland]

How do the British count funny? I know I do as I use a vigesimal system but I cant think of how the British do it generally that's wierd.

 

[AV1611VET]

How do the British count funny?

We say "billion", but they say "million" -- or something like that.

 

[Cabal]

We say "billion", but they say "million" -- or something like that.

Uh...no.

Well, not anymore, at any rate.