Re: Логика за физици

On May 28, 7:43 am, Stoil Marinov <stoil_marinovOBVI...@xxxxxxxxxxx>
wrote:
ivano...@xxxxxxxx wrote:
On May 27, 9:29 pm, Chorbalan <chorba...@xxxxxxx> wrote:
На мене ми изглежда, че при срещата ще са си на еднаква възраст, но
не ми е много ясен ефекта на смана на посоката, в който момент става
коренцията. В wikipedia този момент не е обяснен, та затова питам...

Ne be, Chorbi, njama da sa na ednakva vqzrast pri sreshtata si. Ama-
ha!
Stoil go objasni dobre, nie sme gi uchili v universiteta tezi neshta,
imali sme spetzialni kursove,
ama taka e to, kato se mqchi chovek filosofski samo da razbere neshto
bez da si razpishe uravnenijata ;)
Ponezhe ne si gi uchil tezi neshta v detaili i iskash "filosofijata"
samo -
preporqchvam ti nai-seriozno da prochetesh pone edna k*** na Stephen
Hawking,
Toi objasnjava mnogo dobre. 'The universe in a nutshell' ja ima vqv
vsjaka biblioteka i
ponezhe mi e pod rqka - shte ti tzitiram pasazhi s prostranstveni
objasnenija.
Pqrvo, zabravi za otivaneto i vrqshtaneto. Ami ako se dvizhish v
krqgova orbita? Razbira se,
pak shte imash sqshtija efekt, stiga da ima dvizhenie, sprjamo neshto,
koeto ne e v dvizhenie.

Eto ti malko predistorija i objasnenija, kakto se kazva ot ustata na
konja (Stephen Hawkin):

"In a paper written in June 1905 Einstein pointed out that if one
could not detect weather or not one was moving through space, the
notion of an ether was redundant. Instead, he started from the
postulate that the laws of science should appear the same to all
freely moving observers. In particular, they should all measure the
same speed for light, no matter how fast they were moving. The speed
of light is independent of their motion and is the same in all
directions.

This required abandoning the idea that there is a universal quantity
called time that all clocks would measure.
Instead, everyone would have his or her own personal time. The times
of two people would agree if the people were at rest with respect to
each other, but not if they were moving."

Do tuk beshe teoretichna podgotovka. Sega cheti za eksperimentite:
"One version of the twins paradox:
This has been confirmed by a number of experiments, including one in
which two accurate clocks were flown in opposite directions around the
world and returned showing very slightly different times. The clock in
the aircraft flying toward the west records more time than its twin
travelling in the opposite direction. When they met up again the clock
that flew toward the east had recorded slightly less time.
The time for the passengers in the aircraft flying toward the east is
less than that for those in the aircraft flying toward the west.
This might suggest that if one wanted to live longer, one should keep
flying to the east so that the plane's speed is added to the earth's
rotation. However, the tiny fraction of a second one would gain would
be more than canceled by eating airline meals.

Einstein's postulate that the laws of nature should appear the same to
all freely moving observers was the foundation of theory of
relativity, so called because it implied that only relative motion was
important. Einstein hd overthrown two of the absolutes of 19th-century
science: absolute rest, as represented by the ether, and absolute and
universal time that all clocks would measure.
Many people found this an unsettling concept. Did it imply, they
asked, that 'everything' was relative?
... I still get two or three letters a week telling me that Einstein
was wrong.
Nevertheless, the theory of relativity is now accepted by the
scientific community, and its predictions have been verified in
countless applications.

The twins paradox:
In the theory of relativity each observer has his own measure of time.
This can lead to the so called twins paradox.
One of a pair of twins (a) leaves on a space journet during which he
travels close to the speed of light C, while his brother (b) remains
on Earth.
Because of (a)'s motion, time runs more slowly on the spacecraft as
seen by the earthbound twin. So on his return the space traveler (a2)
will find that his brother (b2) has aged more than himself.
Although it seems against common sense, a number of experiments have
implied that in this scenario the travelling twin would indeed be
younger.

Another one:
A spaceship passes Earth from left to right at four-fifths the speed
of the light. A pulse of light is emitted at one end of the cabin and
reflected at the other end (a).
The light is observed by people on Earth and on the spaceship. Because
of the motion of the spaceship, they will disagree about the distance
the light has traveled in reflecting back (b).
They must therefore also disagree about the time the light has taken,
because according to Einstein's postulate the speed of light is the
same for all freely moving observers."

Доротея, благодаря за разясненията.
На мен в главата ми тази специялна теория на относителността беше
забулена от относителна мъгла на годините. <g>
Преди 4-5 години една вечер тъкмо се бях прибрал от работа и дъщеря ми
се обади със спешен въпрос. Тогава тя учеше физика undergrad в
Uiniversity of Illinois. За домашно имаха една задача, подобна на тази,
която описваш по-горе, но беше по засукана. Не помня вече конкретното
условие на задачата. В крайна сметка трябваше да се отчете разликата във
времето и скъсяването на пространството, за да се намери правилният
отговор, който беше даден. Аз се мъчих около час и вече бях готов да
обява дадения отговор за неверен, когато и Лили се прибра. Веднага беше
мобилизирана и тя да решава задачата. След подробна дискусия, се оказа
че съм изпуснал да отчета един от ефектите на трансформация и затова не
получаваме отговора. Друго си е, когато теоретик се захване с
решававането на задача. Та дъщеря ми си направи домашното и научи нещо
повече.

Стоил

Mojata svekqrva kazvashe: "The smart one gets a smart wife" :) Validno
v tvoja sluchai, a i kakqv hubav genetichen material ste dali na
detzata! :)
.