Piv txwv ntawm Cov Lus Nug Sib Tham Txog Kev Sib Piv
Kev sib piv yog ib qho ntawm cov tswv yim tseem ceeb tshaj plaws hauv kev kawm txog lub ntiaj teb niaj hnub no, uas Albert Einstein tau qhia thaum ntxov xyoo pua 20th. Tsab xov xwm no yuav tham txog txoj kev xav ntawm kev sib piv thiab nws siv rau hauv lub neej txhua hnub los ntawm cov piv txwv teeb meem thiab cov lus piav qhia.
Kev Taw Qhia Txog Kev Sib Txheeb Ze
Txoj kev xav ntawm kev sib raug zoo muaj ob ntu tseem ceeb: Txoj Kev Xav Tshwj Xeeb ntawm Kev Sib Raug Zoo thiab Txoj Kev Xav Dav Dav ntawm Kev Sib Raug Zoo. Txoj Kev Xav Tshwj Xeeb ntawm Kev Sib Raug Zoo, luam tawm xyoo 1905, tau hloov pauv peb txoj kev nkag siab txog qhov chaw thiab lub sijhawm. Hauv txoj kev xav no, Einstein tau hais tias qhov ceev ntawm lub teeb yog qhov txwv ceev tshaj plaws uas tsis tuaj yeem dhau thiab tias cov kev cai ntawm physics yog tib yam rau txhua tus neeg soj ntsuam uas txav mus rau qhov ceev tas li.
Lub sijhawm no, Txoj Kev Tshawb Fawb Txog Kev Sib Txheeb Ze, uas tau qhia tawm xyoo 1915, hais txog lub ntiajteb txawj nqus. Raws li txoj kev tshawb fawb no, lub ntiajteb txawj nqus tsis yog lub zog ib txwm muaj, tab sis yog qhov nkhaus ntawm qhov chaw-lub sijhawm uas tshwm sim los ntawm pawg neeg.
Kev nkag siab txog lub ntsiab lus yooj yim no yog qhov tseem ceeb heev ua ntej peb mus rau hauv cov lus nug piv txwv thiab lawv cov kev sib tham.
Cov Lus Nug Piv Txwv thiab Kev Sib Tham
Lo lus nug 1: Lub sijhawm ncua
Lo lus nug:
Ib tug neeg caij nkoj mus ncig teb chaws mus rau ib lub hnub qub deb ntawm qhov ceev ntawm 0,8c (qhov twg c yog qhov ceev ntawm lub teeb). Yog tias txoj kev mus ncig siv sijhawm 10 xyoo hauv ntiaj teb, tus neeg caij nkoj yuav siv sijhawm ntev npaum li cas raws li nws lub moos (lub sijhawm kom raug)?
Kev Sib Tham:
Lub sijhawm ntev yog ib qho xwm txheej uas tshwm sim vim muaj qhov sib txawv ntawm qhov ceev ntawm ob tus neeg soj ntsuam. Lub sijhawm dhau qeeb dua rau ib yam khoom txav mus rau ib tus neeg soj ntsuam uas nyob ruaj khov.
Cov mis rau kev nthuav dav lub sijhawm yog:
\[ \Delta t' = \frac{\Delta t}{\sqrt{1 – \frac{v^2}{c^2}}}\]
Qhov twg:
- \(\Delta t'\) yog lub sijhawm pom ntawm ib yam khoom txav mus los.
- \(\Delta t\) yog lub sijhawm pom ntawm ib yam khoom nyob ruaj khov.
- \(v\) yog qhov ceev ntawm cov khoom txav mus los.
- \(c\) yog qhov ceev ntawm lub teeb.
Ntsaws cov nqi paub rau hauv cov mis:
\[ v = 0,8c \]
\[ \Delta t = 10 \, \text{xyoo} \]
\[ \Delta t' = \frac{10}{\sqrt{1 – \frac{(0,8c)^2}{c^2}}\]
\[ \Delta t' = \frac{10}{\sqrt{1 – 0,64}}\]
\[ \Delta t' = \frac{10}{\sqrt{0,36}}\]
\[ \Delta t' = \frac{10}{0,6}\]
\[ \Delta t' \approx 16.67 \, \text{year}\]
Yog li, lub sijhawm uas tus neeg caij nkoj mus saum ntuj ntsib raws li nws lub moos yog li 16,67 xyoo.
Lo Lus Nug 2: Kev Txiav Ntev
Lo lus nug:
Ib yam khoom ntev 100 meters thiab ntsuas thaum so. Yog tias yam khoom txav mus los ntawm qhov ceev ntawm 0,6c, qhov ntev ntawm yam khoom yog dab tsi raws li tus neeg soj ntsuam nyob ruaj khov?
Kev Sib Tham:
Qhov ntev contraction yog ib qho phenomenon uas qhov ntev ntawm ib yam khoom txav mus rau tus neeg saib luv dua li thaum yam khoom so.
Cov mis rau kev txiav ntev yog:
\[ L = L_0 \sqrt{1 – \frac{v^2}{c^2}} \]
Qhov twg:
- \(L\) yog qhov ntev ntawm qhov khoom txav mus los.
- \(L_0\) yog qhov ntev tsim nyog (qhov ntev ntawm yam khoom thaum nws so).
- \(v\) yog qhov ceev ntawm cov khoom.
- \(c\) yog qhov ceev ntawm lub teeb.
Ntsaws cov nqi paub rau hauv cov mis:
\[ L_0 = 100 \, \text{meter} \]
\[ v = 0,6c \]
\[ L = 100 \sqrt{1 – \frac{(0,6c)^2}{c^2}}\]
\[L = 100 \sqrt{1 – 0,36}\]
\[ L = 100 \sqrt{0,64}\]
\[ L = 100 \times 0,8\]
\[ L = 80 \, \text{meter}\]
Yog li, qhov ntev ntawm cov khoom txav mus los raws li tus neeg soj ntsuam ruaj khov yog 80 meters.
Lo lus nug 3: Relativistic Mass
Lo lus nug:
Ib lub khoom me me muaj qhov hnyav so ntawm 2 kg. Yog tias lub khoom me me no txav mus rau qhov ceev ntawm 0,9c, qhov hnyav relativistic ntawm lub khoom me me yog dab tsi?
Kev Sib Tham:
Qhov hnyav sib piv yog qhov hnyav ntawm ib yam khoom uas nce ntxiv thaum yam khoom txav mus ze rau qhov ceev ntawm lub teeb.
Tus qauv ntawm cov pawg relativistic yog:
\[ m = \frac{m_0}{\sqrt{1 – \frac{v^2}{c^2}}} \]
Qhov twg:
- \(m\) yog qhov hnyav relativistic.
- \(m_0\) yog qhov hnyav seem (qhov hnyav kom raug).
- \(v\) yog qhov ceev ntawm cov khoom.
- \(c\) yog qhov ceev ntawm lub teeb.
Ntsaws cov nqi paub rau hauv cov mis:
\[ m_0 = 2 \, \text{kg} \]
\[ v = 0,9c \]
\[ m = \frac{2}{\sqrt{1 – \frac{(0,9c)^2}{c^2}}\]
\[ m = \frac{2}{\sqrt{1 – 0,81}}\]
\[ m = \frac{2}{\sqrt{0,19}}\]
\[ m \approx \frac{2}{0,436}\]
\[ m \approx 4,59 \, \text{kg}\]
Yog li, qhov hnyav relativistic ntawm lub particle thaum txav mus los ntawm qhov ceev ntawm 0,9c yog li 4,59 kg.
Lo lus nug 4: E=mc^2
Lo lus nug:
Yog tias 1 gram ntawm ib yam khoom raug rhuav tshem tag raws li Einstein tus qauv \(E=mc^2\) yuav tsim tau zog ntau npaum li cas?
Kev Sib Tham:
Einstein tus qauv nto moo \(E=mc^2\) muab kev sib raug zoo ncaj qha ntawm pawg (m) thiab lub zog (E), nrog \(c\) yog qhov ceev ntawm lub teeb.
Hauv SI (International System of Units) system:
– Qhov hnyav (m) yog ntsuas hauv kilograms (kg).
- Qhov ceev ntawm lub teeb (c) yog \(3 \times 10^8 \, \text{m/s}\).
Cia peb xam lub zog uas tsim los ntawm 1 gram ntawm ib yam khoom:
– 1 gram = 0,001 kg
\[ E = mc^2 \]
\[ E = (0,001) (3 \times 10^8)^2 \]
\[ E = (0,001) (9 \times 10^{16}) \]
\[ E = 9 \times 10^{13} \, \text{joules} \]
Yog li, lub zog tsim tawm yog tias 1 gram ntawm cov khoom raug rhuav tshem tag nrho yog ∑ (9 lub sijhawm 10^{13}) joules.
Xaus
Kev sib piv yog ib lub tswv yim tseem ceeb thiab tseem ceeb hauv kev kawm txog lub cev, nrog rau kev cuam tshuam tob rau ntau yam xwm txheej ntawm lub cev. Los ntawm cov piv txwv uas tau tham saum toj no, peb tau pom tias txoj kev xav tshwj xeeb ntawm kev sib piv tuaj yeem siv los nkag siab txog kev nthuav dav ntawm lub sijhawm, kev sib txuas ntawm qhov ntev, qhov hnyav ntawm kev sib piv, thiab kev sib raug zoo ntawm qhov hnyav thiab lub zog.
Los ntawm kev nkag siab thiab xyaum ua cov teeb meem no, peb tuaj yeem txaus siab rau qhov zoo nkauj ntawm txoj kev xav ntawm kev sib piv thiab nws cov txiaj ntsig rau kev nkag siab lub ntiaj teb.
