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Joker
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21 Apr 2012, 3:12 am

So how likes Physics? I love Physics so basically talk about anything that has to do with Physics I will start.

Internal energy is the sum of temperature (ke) and phase (pe) conditions.
Steam and liquid water molecules at 100 degrees have equal kinetic energies.
Degrees Kelvin (absolute temp.) Is equal to zero (0) degrees Celsius.
Temperature measures the average kinetic energy of the molecules.
Phase changes are due to potential energy changes.
Internal energy always flows from an object at higher temperature to one of lower temperature.



Stargazer43
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21 Apr 2012, 11:50 am

I have a love/hate relationship with physics. In that I love it when I can solve the problems and hate it when I can't.

Quote:
Internal energy always flows from an object at higher temperature to one of lower temperature.

That's actually heat transfer, internal energy comprises more than just heat transfer. Since dU=dq+PdV, where PdV=work, dU=change in internal energy and dq=change in heat, you can change the internal energy of a system without any heat transfer into or out of said system.

Quote:
Degrees Kelvin (absolute temp.) Is equal to zero (0) degrees Celsius.

Not sure I follow you here...at 0 C the temperature would be 273.15 K. 0 Kelvin is absolute zero, where molecules would have no motion at all (not achieved yet but we've come pretty darn close!).



Joker
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21 Apr 2012, 2:22 pm

Stargazer43 wrote:
I have a love/hate relationship with physics. In that I love it when I can solve the problems and hate it when I can't.

Quote:
Internal energy always flows from an object at higher temperature to one of lower temperature.


That's actually heat transfer, internal energy comprises more than just heat transfer. Since dU=dq+PdV, where PdV=work, dU=change in internal energy and dq=change in heat, you can change the internal energy of a system without any heat transfer into or out of said system.

True but it was jut a formual as a good start to a talk about physics.

Quote:
Degrees Kelvin (absolute temp.) Is equal to zero (0) degrees Celsius.

Not sure I follow you here...at 0 C the temperature would be 273.15 K. 0 Kelvin is absolute zero, where molecules would have no motion at all (not achieved yet but we've come pretty darn close!).


In deed it is very close. Do you have a favorite physicist.



Kurgan
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21 Apr 2012, 3:14 pm

Sadly, physics were only a part of the first semester at my university, but I loved this subject. I particularly liked the chapters on energy.



Last edited by Kurgan on 21 Apr 2012, 3:15 pm, edited 1 time in total.

Joker
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21 Apr 2012, 3:15 pm

Kurgan wrote:
Sadly, Physics weremonlyma partmof,the ferst semester at my umiversity, but I loved this subject. I particularly liked the chapters on energy.


Yes me to I love the chapters on energy as well.



Widman
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24 May 2012, 2:23 pm

i am also interested and fascinated by physics. I have though spent far to little time getting into the the subject. The only real book i have read on the subject is Relativity: The Special and the General Theory by Albert Einstein i do though understand physics quite easily.
Could anyone recommend a good general book on physics ?
i am also interested in theoretical physics but i know little of it. my other interests get in the way of me entering the glorious path of the physicist :?



ruveyn
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24 May 2012, 3:03 pm

Widman wrote:
i am also interested and fascinated by physics. I have though spent far to little time getting into the the subject. The only real book i have read on the subject is Relativity: The Special and the General Theory by Albert Einstein i do though understand physics quite easily.
Could anyone recommend a good general book on physics ?
i am also interested in theoretical physics but i know little of it. my other interests get in the way of me entering the glorious path of the physicist :?


The 3 volume set -The Feynman Lectures- edited by Leighton and Sand

ruveyn



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24 May 2012, 3:44 pm

Thank you for reminding me... I still need to crack open that giant physics book for class next semester.
F=MA.



ruveyn
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24 May 2012, 4:15 pm

Evinceo wrote:
Thank you for reminding me... I still need to crack open that giant physics book for class next semester.
F=MA.


More generally F = dp/dt where p is momentum. This is true even in special relativity where mass is velocity dependent.

ruveyn



Last edited by ruveyn on 24 May 2012, 7:55 pm, edited 1 time in total.

kill231
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24 May 2012, 4:39 pm

My favorite part of physics is theoretical physics because you never know what the correct answer is until all the ticks are checked.


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ruveyn
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25 May 2012, 5:20 am

kill231 wrote:
My favorite part of physics is theoretical physics because you never know what the correct answer is until all the ticks are checked.


In physics the correct question is more important than the correct answer.

ruveyn



Widman
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25 May 2012, 10:58 am

The 3 volume set -The Feynman Lectures- edited by Leighton and Sand

ruveyn[/quote]

I looked it up. It seems to be a great work though it also is expensive. I will have to get it when i have some money. (if the city liberty does not have it)



pete1061
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25 May 2012, 11:04 am

I love physics. I aced it in high school without even making an effort.

But I don't know how much there is to actually talk about.
I enjoy just studying the behavior of the universe around me than actually discussing it.


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ruveyn
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25 May 2012, 2:26 pm

Widman wrote:
The 3 volume set -The Feynman Lectures- edited by Leighton and Sand

ruveyn


I looked it up. It seems to be a great work though it also is expensive. I will have to get it when i have some money. (if the city liberty does not have it)[/quote]

You can get the set or individual items used. You can get a used volume in at least good condition through Amazon for under 20 bucks.

ruveyn



ScottTheSculptor
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29 May 2012, 1:43 pm

Feynman Lectures, have 'em, luv 'em.

But. . . I wouldn't consider it "basic".
It is very math oriented.

If you have a story about how things connect before you "learn" physics you will be better off.

Survey technologies - metalworking, woodworking, ceramics, semiconductors, and engineering drawing (abstraction skills) . . . *then* read Feynman and you will have references in the real world to connect to.

Asimov's "Guide to Science" was really helpful for me, but it's pretty old :-)


I quit physics when it got theoretical.
It has an error so it *can't* make sense- 80% of the universe is missing.
(I eventually fixed it but no physicist will accept a solution from "outside")


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29 May 2012, 6:26 pm

ruveyn wrote:
kill231 wrote:
My favorite part of physics is theoretical physics because you never know what the correct answer is until all the ticks are checked.


In physics the correct question is more important than the correct answer.

ruveyn


a fact that a great many people miss or forget.
well said.