Yuav ua li cas thiaj nrhiav tau tus coefficient ntawm kev sib txhuam: kev sim

2024 Tus sau: Angel Austin | [email protected]. Kawg hloov kho: 2024-01-02 17:48

Kev sib txhuam yog cov txheej txheem ntawm lub cev uas tsis muaj kev txav mus los hauv peb lub ntiaj teb yuav tsis muaj nyob. Nyob rau hauv physics, los xam tus nqi ntawm cov kev sib txhuam quab yuam, nws yog tsim nyog los paub ib tug tshwj xeeb coefficient rau lub rubbing nto nyob rau hauv kev saib xyuas. Yuav nrhiav kev sib txhuam coefficient li cas? Kab lus no yuav teb lo lus nug no.

Kev sib txhuam hauv physics

Ua ntej teb cov lus nug ntawm yuav ua li cas thiaj nrhiav tau cov coefficient ntawm kev sib txhuam, nws yuav tsum tau txiav txim siab seb qhov kev sib txhuam yog dab tsi thiab nws lub zog yog dab tsi.

Hauv physics, muaj peb hom txheej txheem no tshwm sim ntawm cov khoom siv. Qhov no yog kev sib txhuam ntawm so, zawv zawg thiab dov. Kev sib txhuam ib txwm tshwm sim thaum lub zog sab nraud sim txav ib qho khoom. Kev sib txhuam zawv zawg, raws li lub npe qhia, tshwm sim thaum ib qho chaw swb hla lwm qhov. Thaum kawg, dov kev sib txhuam tshwm sim thaum ib puag ncig khoom (lub log, pob) yob ntawm qee qhov chaw.

Txhua yam muaj sib xws yog qhov tseeb tias lawv txwv tsis pub leej twgkev txav mus los thiab qhov taw tes ntawm kev thov ntawm lawv lub zog yog nyob rau hauv thaj tsam ntawm kev sib cuag ntawm qhov chaw ntawm ob yam khoom. Tsis tas li ntawd, tag nrho cov hom no hloov txhua lub zog rau hauv cov cua sov.

Lub zog ntawm zawv zawg thiab kev sib txhuam zoo li qub yog tshwm sim los ntawm kev siv lub ntsej muag me me ntawm qhov chaw uas rub. Tsis tas li ntawd, cov hom no yog vim dipole-dipole thiab lwm hom kev sib cuam tshuam ntawm atoms thiab molecules uas tsim lub cev txhuam.

Qhov ua rau dov kev sib txhuam yog cuam tshuam nrog hysteresis ntawm elastic deformation uas tshwm ntawm qhov chaw ntawm kev sib cuag ntawm cov khoom dov thiab qhov chaw.

Kev sib txhuam quab yuam thiab coefficient ntawm kev sib txhuam

Txhua peb hom kev sib txhuam sib zog tau piav qhia los ntawm cov kab lus uas muaj tib daim ntawv. Nov yog nws:

F_t=µ_tN.

Ntawm no N yog lub zog ua haujlwm perpendicular rau saum npoo ntawm lub cev. Nws hu ua qhov kev txhawb nqa. Tus nqi µ_{t- yog hu ua tus coefficient ntawm qhov sib thooj ntawm kev sib txhuam.}

Coefficients rau zawv zawg thiab so kev sib txhuam yog qhov tsis muaj qhov ntau. Qhov no tuaj yeem nkag siab los ntawm kev saib qhov sib npaug ntawm kev sib txhuam quab yuam thiab kev sib txhuam coefficient. Sab laug ntawm qhov sib npaug yog qhia nyob rau hauv newtons, sab xis kuj qhia nyob rau hauv newtons, vim N yog ib tug quab yuam.

Raws li kev sib txhuam dov, cov coefficient rau nws kuj yuav yog qhov tsis muaj nuj nqis, txawm li cas los xij, nws txhais tau tias yog qhov piv ntawm cov yam ntxwv ntawm cov qauv elastic deformation rau lub vojvoog ntawm cov khoom dov.

Nws yuav tsum tau hais tias qhov tseem ceeb ntawm cov coefficients ntawm zawv zawg thiab so kev sib txhuam yog feem kaum ntawm ib chav tsev. Rau kev sib txhuamdov, qhov coefficient no sib raug mus rau pua pua thiab txhiab ntawm ib chav.

Yuav ua li cas thiaj nrhiav tau tus coefficient ntawm kev sib txhuam?

Coefficient µ_{tnyob ntawm ntau yam uas nyuaj rau kev suav lej. Peb teev ib co ntawm lawv:}

• khoom ntawm cov khoom siv txhuam;
• nrawm zoo;

Yuav muaj av, dej thiab lwm yam;

• qhov kub thiab txias.

Yog li ntawd, tsis muaj qauv rau µ_t, thiab nws yuav tsum tau ntsuas kev sim. Txhawm rau kom nkag siab yuav ua li cas thiaj nrhiav tau tus coefficient ntawm kev sib txhuam, nws yuav tsum tau qhia los ntawm tus qauv rau F_{t. Peb muaj:}

µ_t =F_t/N.

Nws hloov tawm tias kom paub µ _{tnws yog qhov tsim nyog los nrhiav kev sib txhuam quab yuam thiab txhawb kev tawm tsam.}

Qhov kev sim sib raug tau ua raws li hauv qab no:

1. Siv lub cev thiab lub dav hlau, piv txwv li, ua los ntawm ntoo.
2. Cling lub dynamometer rau lub cev thiab sib npaug txav mus rau saum npoo.

Tib lub sijhawm, lub dynamometer qhia qee qhov quab yuam, uas yog sib npaug rau F_{t. Cov tshuaj tiv thaiv hauv av yog sib npaug ntawm qhov hnyav ntawm lub cev ntawm kab rov tav.}

Cov txheej txheem piav qhia tso cai rau koj kom nkag siab qhov coefficient ntawm qhov zoo li qub thiab zawv zawg kev sib txhuam yog dab tsi. Ib yam li ntawd, koj tuaj yeem sim txiav txim siab µ_trolling.

Lwm txoj kev sim rau kev txiav txim siab µ_{t yog muab rau hauv daim ntawv ntawm qhov teeb meem hauv kab lus tom ntej.}

Teeb meem suav µt

Cov nqaj ntoo yog nyob ntawm iav nto. Los ntawm smoothly tilting saum npoo, peb pom tias zawv zawg ntawm lub beam pib ntawm lub kaum sab xis ntawm inclination ntawm 15o. Dab tsi yog qhov coefficient ntawm kev sib txhuam zoo li qub rau ib khub ntoo-iav?

Thaum lub nqaj nyob ntawm lub dav hlau inclined ntawm 15 o, ces qhov kev sib txhuam ntawm qhov seem rau nws muaj qhov siab tshaj plaws. Nws yog sib npaug rau:

F_t=mgsin(α).

Force N yog txiav txim los ntawm tus qauv:

N=mgcos(α).

Thov cov mis rau µ_{t, peb tau txais:}

µ_t=F_{t/N=mgsin(α)/(mgcos(α))=tg(α).}

Hloov lub kaum sab xis, peb tuaj txog ntawm cov lus teb: µ_{t=0, 27.}