Nyob rau lo lus nug ib txwm "Puas yog ib litre dej hnyav?" Cov neeg feem coob yuav muab saib hauv phau ntawv qhia, lossis yooj yim hais tias, "Ib kilogram." Tseeb, ntawm qhov kub ntawm 40 0 C thiab nyob rau hauv ib txwm atmospheric siab, qhov hnyav ntawm ib liter
distilled, uas yog, tsis muaj impurities, dej yog raws nraim 1 kg. Thiab leej twg tuaj yeem teb cov lus nug "Yuav ua li cas npaum li cas ntawm ib liter dej los ntawm lub caij nplooj ntoos hlav ntsev hnyav?" los yog "Dej twg hnyav dua - kub lossis txias?"
Yuav kom tsis txhob muaj teeb meem, koj yuav tsum paub koj tus kheej nrog qee cov cai ntawm physics. Yog xav paub ntxiv, nws yuav tsum tau muab sau tseg tam sim ntawd hauv peb tsab xov xwm peb yuav tsis tham txog qhov hnyav ntawm dej, tab sis txog nws qhov loj. Qhov sib txawv ntawm cov ntsiab lus no yog qhov loj yog qhov tseem ceeb ntawm qhov ntsuas ntawm qhov teeb meem, thiab ntsuas hauv kilograms, thiab qhov hnyav yog tus nqi qhia tias lub cev muaj zog npaum li cas nrog rau qee qhov loj ntawm qhov chaw; nws chav tsev yog Newton.
Yuav teb cov lus nug txog 1 litre dej hnyav npaum li cas, ua ntej peb saib seb qhov ntsuas twg ua rau lub cev hnyav. Los ntawm chav kawm ntawm physicsPeb paub tias huab hwm coj yog khoom
ntom ntawm cov teeb meem ntawm cov coefficient ntawm lub caij nplooj zeeg dawb acceleration, uas yog kwv yees tib yam ntawm tag nrho cov saum npoo ntawm peb ntiaj chaw thiab yog sib npaug rau 9.81 kg/m2. Qhov kev hloov pauv ntawm ob qhov ntau no ua rau peb qhov sib txawv ntawm qhov loj ntawm tib yam khoom raws li qhov sib txawv.
Ua ntej, cia peb tham txog qhov ntom ntom ntawm cov kua. Raws li tau hais los saum no, qhov ceev ntawm cov dej ntshiab hauv ib txwm muaj yog 1000 g / m 3. Yog hais tias impurities, xws li ntsev, ntxiv rau nws, ces qhov ceev yuav nce, thiab dej yuav hnyav dua. Raws li kev cia siab ntawm qhov loj ntawm cov khoom ntawm qhov kub thiab txias, tag nrho cov ntsiab lus ntawm no yog nyob rau hauv cov khoom ntawm cov khoom kom nthuav dav thaum rhuab. Qhov no txhais tau hais tias qhov kev ncua deb ntawm cov molecules yuav loj dua, thiab lawv tag nrho cov naj npawb ntawm ib chav tsev ntim txo, yog li ntawd, cov khoom yuav sib dua. Txawm li cas los xij, dej muaj cov khoom tshwj xeeb - nws nthuav tsis tau tsuas yog thaum cua sov, tab sis kuj thaum txias (nws yog vim qhov no uas cov kav dej tawg thaum lub caij ntuj no). Dej muaj qhov ceev tshaj plaws ntawm qhov khov txias, nrog kev sib txawv me me, nrog kev sib txawv me me ntawm cov nplai ntawm cov nplai, nws ua ntais. Ib liter dej hnyav npaum li cas ntawm qhov kub thiab txias, yog tias koj xav tau, koj tuaj yeem saib hauv phau ntawv siv.
Atmospheric siab tsis cuam tshuam cov kua dej ntau npaum li cas
kub, thiab qhov tshwm sim ntawm nws qhov kev ua yog qhov sib txawv ntawm qhov kub thiab txias. Thaum lub siab siab, qhov kev ncua deb ntawm cov molecules txo qis, yog li ntawd, tib lub ntim yuav suav nrogntau yam khoom. Raws li qhov tshwm sim, muaj qhov nce hauv huab hwm coj. Qhov no tuaj yeem pom tau yooj yim hauv kev xyaum, yog tias koj hnyav ib lub tog raj kheej ntawm cov cua compressed thiab tib lub tog raj kheej nrog cua nyob rau hauv ib txwm siab.
Los ntawm txoj kev, koj puas paub tias pes tsawg litre dej hnyav ntawm tus ncej? 0.5 feem pua ntau tshaj ntawm kab zauv. Qhov tshwm sim no yog vim kev sib hloov ntawm lub ntiaj teb nyob ib ncig ntawm nws axis. Vim yog nws, qhov centrifugal acceleration nce thaum koj mus txog ntawm txoj kab nruab nrab thiab, yog li ntawd, acceleration ntawm lub ntiajteb txawj nqus nce.
xav li no, koj tuaj yeem xam ntau npaum li cas ib liter ntawm cov kua hnyav, thiab qhov ntsuas no yuav hloov pauv li cas nyob ntawm ib puag ncig.
