Lub angular momentum: nta Khoom Txhua yam

Angular momentum yog ib tug yuav tsum muaj, yuav tsum muaj kev cai lij choj ntawm xwm. Nws yog ncaj qha kev cob cog rua nrog lub symmetry thaj chaw ntawm qhov chaw ntawm lub ntiaj teb no nyob rau hauv uas peb txhua tus nyob. Vim txoj kev cai nws txoj kev txuag, momentum lub sij lub li ib txwm rau peb lub cev cov cai ntawm cov lus tsa suab ntawm cov ntaub ntawv uas lub cev nyob rau hauv qhov chaw. Qhov no tus nqi nruab nrab yog tus nqi ntawm cov Translational los yog muab tsab ntawv tsa suab.

Lub angular momentum, kuj hu ua ib tug "kev tig tau", "angled" thiab "orbital", nws yog ib qho tseem ceeb cov yam ntxwv, uas yog nyob rau hauv cov ntaub ntawv ntawm lub cev hnyav, nws muab faib rau cov yam ntxwv nrog rau kev hwm mus ib xav txog tej yam reference axis thiab tus mus ceev. Nws yuav tsum tau clarified tias nyob rau hauv lub mechanics ntawm kev sib hloov muaj ib tug dav heev kev txhais. Txawm linear tsab ntawv tsa suab los ntawm ib tug tej yam arbitrary point dag nyob rau hauv lub qhov chaw muaj peev xwm yuav tau ua sib hloov mus los, noj nws los ntawm cov xav txog tej yam axis.

Angular momentum thiab cov kev cai ntawm kev txuag ntawm nws formulated, Rene Descartes thov kom translationally tsiv system cov ntaub ntawv uas cov ntsiab lus. Txawm li cas los, kom muaj lub teb tsab ntawv tsa suab hom nws ho tsis hais. Tsuas yog xyoo tom qab Leonardom Eylerom, thiab ces lwm Swiss paub txog, physicist thiab mathematician Daniel Bernoulli txoj kev tshawb no cov ntaub ntawv uas system kev sib hloov hais txog ib tug tsau central axis, nws twb xaus lus tias rau no hom ntawm lub zog nyob rau hauv qhov chaw ua muab txoj cai lij choj.

Ntxiv tshawb tau siab paub tseeb tias nyob rau hauv lub qhaj ntawv ntawm sab nraud cawv sum ntawm cov khoom luj ntawm tag nrho cov ntsiab lus ntawm cov tag nrho lawv ceev thiab qhov kev ncua deb mus rau lub chaw ntawm kev sib hloov tseem unchanged. Me ntsis tom qab, tus Fabkis tus paub txog Patrikom Darsi cov lus tau qhia nyob rau hauv cov nqe lus ntawm lub cheeb tsam swept los ntawm lub voos kheej-kheej vectors ntawm elementary hais rau tib lub sij hawm lub sij hawm. Qhov no pub rau txog angular momentum ntawm ib tug cov ntaub ntawv uas taw tes nrog ib co paub xilethi-aus mechanics postulates thiab, nyob rau hauv particular, rau qhov tseem ceeb rau txoj hauj lwm ntawm planetary cov lus tsa suab Ioganna Keplera.

Lub caij ntawm momentum ntawm ib tug nruj heev lub cev - peb dynamic nce mus nce los mus uas tus siv kev cai hauv paus kev cai lij choj ntawm kev txuag. Nws hais tias hais txog ntawm lub qhov thiab hom ntawm tsab ntawv tsa suab nyob rau hauv qhov qhaj ntawv los ntawm sab nraud cawv no tus nqi nyob rau hauv ib tug raug rho tawm cov ntaub ntawv uas system yuav yeej ib txwm nyob twj ywm unchanged. Qhov no lub cev tivthaiv tej zaum yuav undergo ib co kev hloov xwb nyob rau hauv cov ntaub ntawv uas tsis yog-xoom lub caij ntawm tej yam rog.

Los ntawm txoj kev cai no kuj qhia tau hais tias hais tias yog M = 0, muaj kev hloov nyob rau hauv qhov kev ncua deb ntawm lub cev (cov ntaub ntawv uas taw tes system) thiab lub hauv paus kev sib hloov axis tas ua ib qho kev nce los yog txo nyob rau hauv nws tus nqi ntawm kev sib hloov nyob ib ncig ntawm qhov chaw. Piv txwv li, ib tug txawj dhia nrig nphau ua ntog ua las ncas nyob rau hauv cov huab cua mus ua ib tug ob peb lem, chiv dov nws lub cev mus rau hauv ib lub pob. Ib tug ballerina los yog daim duab skater rotates nyob rau hauv pirouette, bred ob txhais tes nyob rau hauv tes, yog hais tias lawv xav mus qeeb, thiab vice versa, nias kom lawv lub cev, thaum ua tau saws ntawm ib tug ntau dua ceev. Yog li, nyob rau hauv kev ua si nawv thiab art ntawm siv qhov siv txoj cai lij choj ntawm xwm.