Pepala la Fizikiki pa Mafunde a Phokoso
Pendauluan
Mafunde a phokoso ndi chinthu chogwirizana kwambiri ndi moyo watsiku ndi tsiku. Phokoso limalola anthu kulankhulana kudzera mu zokambirana, kusangalala ndi nyimbo, komanso kugwiritsa ntchito ukadaulo monga mafoni, sonar, ndi zida zamagetsi pazachipatala. Mwakuthupi, phokoso ndi mafunde amakina zomwe zimafuna sing'anga kuti ifalikire, mosiyana ndi mafunde amagetsi monga kuwala komwe kumatha kufalikira mu vacuum. mafunde a phokoso ikufotokoza momwe mawu amapangikira, momwe mawu amafalitsira, zinthu zomwe zimakhudza liwiro la kufalikira, ndi makhalidwe omwe amatsimikiza kukwera ndi mphamvu ya mawu. Pepalali likufotokoza za momwe mawu amagwiritsidwira ntchito. mfundo zoyambira za mafunde mawu, ma equation ofunikira, ndi zina mwa ntchito zawo.
Mfundo Zoyambira Mafunde a Phokoso
Mafunde a phokoso akuphatikizapo mafunde amakina Longitudinal. Imatchedwa yamakina chifukwa imafuna sing'anga (mpweya, madzi, kapena cholimba), ndipo imatchedwa longitudinal chifukwa njira yogwedera kwa tinthu ta sing'anga imafanana ndi njira yofalikira kwa mafunde. Pamene gwero la mawu likugwedezeka—monga foloko yolumikizira kapena nembanemba ya sipika—kugwedezekako kumayambitsa kugwedezeka ndi kusakhalapo kwa zinthu m'malo ozungulira. Kachitidwe kameneka ka kugwedezeka ndi kusakhalapo kwa zinthu kumafalikira ngati mafunde a mawu.
Phokoso lili ndi kuchuluka kofunikira, kuphatikizapo ma frequency, period, wavelength, ndi liwiro. Ma frequency (f) amasonyeza chiwerengero cha kugwedezeka pa sekondi iliyonse mu hertz (Hz). Period (T) ndi nthawi ya kugwedezeka kamodzi, kotero ubale wotsatirawu umagwira ntchito:
f = 1/T.
Kutalika kwa mafunde (λ) ndi mtunda pakati pa kupsinjika kawiri kotsatizana kapena kukulitsa kawiri kotsatizana, pomwe liwiro la mafunde (v) limakwaniritsa equation yonse ya mafunde:
v = λ f .
Chiyerekezochi chikuwonetsa kuti pa chinthu china, liwiro la kufalikira likhoza kuonedwa ngati lokhazikika (pazifukwa zina), kotero kuti kutalika kwa mafunde kumakhala kofanana ndi mafupipafupi.
Liwiro la Phokoso ndi Zinthu Zomwe Zimakhudza Phokosolo
Liwiro la mawu limadalira kwambiri makhalidwe a cholumikizira. Kawirikawiri, mawu amayenda mofulumira kwambiri mu zinthu zolimba, kenako mu zamadzimadzi, komanso pang'onopang'ono kwambiri mu mpweya. Izi zikugwirizana ndi kuchuluka ndi kusinthasintha kwa cholumikizira. Zinthu zolimba zimakhala ndi kusinthasintha kwakukulu, zomwe zimathandiza kuti kugwedezeka kutumizidwe mwachangu.
Mu mpweya pa 0°C, liwiro la phokoso ndi pafupifupi 331 m/s. Liwiro la phokoso mumlengalenga limawonjezeka ndi kutentha kokwera, komwe nthawi zambiri kumayerekezeredwa ndi njira iyi:
v ≈ 331 + 0,6T
ndi T mu °C. Izi zikutanthauza kuti pa 20°C liwiro la mawu ndi pafupifupi 331 + 0,6(20) = 343 m/s. Zinthu zina monga chinyezi zimakhudzanso liwiro chifukwa zimasintha kuchuluka kwa mpweya. Mpweya wonyowa kwambiri umakonda kuwonjezera liwiro la mawu pang'ono poyerekeza ndi mpweya wouma.
Mphamvu ya Phokoso ndi Mphamvu ya Phokoso
Mphamvu ya mawu (I) ndi mphamvu ya mafunde a mawu omwe amalowa m'dera linalake pa sekondi, yoyezedwa mu watts pa mita imodzi (W/m²). Mphamvu imatsimikiza kuchuluka kwa phokoso. Pamene mtunda wochokera ku gwero la mawu ukuwonjezeka, mphamvu nthawi zambiri imachepa chifukwa mphamvu imafalikira pa dera lalikulu. Pa gwero la mfundo lomwe limatulutsa mofanana, mphamvuyo imakhala yofanana ndi sikweya ya mtunda:
I ∝ 1/r².
Kawirikawiri, mulingo wa mphamvu ya mawu (β) umagwiritsidwa ntchito mu ma decibel (dB) chifukwa khutu la munthu limayankha mawu motsatira logarithmic. Fomula yake ndi iyi:
β = 10 log(I/I₀)
ndi I₀ = 10⁻¹² W/m² ngati malire a mphamvu ya kumva kwa anthu. Mawu okhala ndi β pafupifupi 0 dB ndi malire a kumva, pomwe mawu opitilira 120 dB angayambitse kupweteka kapena kuwonongeka kwa kumva. Sikelo iyi imathandiza kuyeza kuchuluka kwa phokoso la chilengedwe, mwachitsanzo m'misewu yayikulu kapena m'mafakitale.
Mafupipafupi, Phokoso, ndi Timbre
Kuchuluka kwa mafunde a mawu kumagwirizana ndi momwe mawu amamvekera. Mawu okwera kwambiri amakhala ndi ma frequency apamwamba, pomwe mawu otsika amakhala ndi ma frequency otsika. Nthawi zambiri anthu amamva kuyambira 20 Hz mpaka 20.000 Hz. Mawu omwe ali pansi pa 20 Hz amatchedwa infrasonic, pomwe omwe ali pamwamba pa 20 kHz amatchedwa ultrasound.
Kupatula phokoso, palinso mtundu wa mawu, kapena timbre, womwe umasiyanitsa zida zoimbira, ngakhale zomwe zili ndi ma frequency ofanana. Timbre imakhudzidwa ndi kapangidwe ka harmonic, komwe ndi ma multiples a ma frequency oyambira omwe amachokera ku ma waveform ovuta. Mwachitsanzo, piyano ndi gitala yomwe ikusewera note "A" (440 Hz) imamvekabe mosiyana chifukwa cha ma harmonics osiyanasiyana.
Zochitika mu Mafunde a Phokoso
Zochitika zina zofunika kwambiri m'mafunde a mawu ndi monga kuwunikira, kusinthasintha, kusinthasintha, kusokoneza, ndi kusinthasintha.
1. Kuwunikira kwa mawu (kumveka bwino ndi kubwerezabwereza)
Kuwunikira kwa mawu kumachitika pamene mafunde a phokoso agunda pamalo olimba. Ngati phokoso lowunikiralo lamveka bwino pambuyo pa phokoso loyambirira, limatchedwa echo. Ngati kuwunikirako kukugwirizana, zomwe zimapangitsa kuti phokoso likhale lalitali, limatchedwa reverberation.
2. Kusinthasintha kwa mawu
Kusinthasintha kwa phokoso kumachitika pamene phokoso likuyenda kudzera mu sing'anga yokhala ndi kutentha kapena kuchulukana kosiyana, zomwe zimasintha liwiro lake. Mwachitsanzo, usiku, mpweya womwe uli pafupi ndi nthaka umakhala wozizira, zomwe zimathandiza kuti phokoso liziyenda kutali m'mikhalidwe ina.
3. Kusinthasintha
Kusinthasintha kwa mawu ndi kupindika kwa mafunde pamene akudutsa m'mipata kapena m'mbali mwa zotchinga. Mawu amatha kusinthasintha mosavuta chifukwa kutalika kwa mafunde ake ndikutalika. Ichi ndichifukwa chake mawu amatha kumvekabe ngakhale gwero lake lili kumbuyo kwa khoma kapena chitseko.
4. Kusokoneza
Kusokoneza ndi kuphatikiza kwa mafunde awiri omwe amachititsa kuti phokoso lizikula (lomangika) kapena lochepa (lowononga). Kusokoneza mawu kungagwiritsidwe ntchito muukadaulo woletsa phokoso popanga mafunde omwe sali pagawo.
5. Kumveka bwino
Kumveka bwino kwa mawu kumachitika pamene dongosolo limagwedezeka mwamphamvu pa ma frequency enaake omwe ali ofanana kapena ofanana ndi ma frequency ake achilengedwe. Zitsanzo za kumveka bwino kwa mawu zimaphatikizapo zida zoimbira monga zitoliro, magitala, ndi zida za chitoliro, komwe mpweya umamveka bwino, zomwe zimapangitsa kuti phokoso likhale lalikulu.
Kugwiritsa Ntchito Mafunde a Phokoso
Mafunde a phokoso amagwiritsidwa ntchito kwambiri mu ukadaulo ndi sayansi. Mu zamankhwala, mafunde a ultrasound amagwiritsidwa ntchito mu ultrasound (ultrasound) kuti aone ana osabadwa kapena ziwalo zamkati popanda opaleshoni. Mu sayansi yoyendera ndi yokhudza nyanja, sonar imagwiritsa ntchito kuwunikira kwa mafunde a phokoso kuti iyeze kuya kwa nyanja kapena kuzindikira zinthu za m'madzi. Mu mafakitale, ma ultrasound amagwiritsidwa ntchito kuti azindikire ming'alu muzinthu (kuyesa kosawononga) komanso kuyeretsa zinthu zazing'ono pogwiritsa ntchito kugwedezeka kwamphamvu.
Mu njira zolumikizirana, maikolofoni amasintha mafunde amawu kukhala ma siginecha amagetsi, pomwe ma siginecha amasintha ma siginecha amagetsi kukhala mafunde amawu. Pomanga ma acoustics, chidziwitso cha kuwunikira ndi kuyamwa kwa mawu chimagwiritsidwa ntchito popanga ma konsati kuti akwaniritse bwino mawu ndikuchepetsa kugwedezeka kwambiri.
Mapeto
Mafunde a mawu ndi mafunde a makina otalika omwe amafunikira sing'anga kuti afalikire. Makhalidwe a mawu amatha kufotokozedwa kudzera mu kuchuluka kwa mawu monga mafupipafupi, kutalika kwa nthawi, liwiro, ndi mphamvu. Liwiro la mawu limakhudzidwa ndi mtundu wa sing'anga ndi kutentha, pomwe kuzindikira phokoso kumakhudzana ndi mphamvu ndi mulingo wa mphamvu mu ma decibel. Zochitika monga kuwunikira, kusokoneza, kusinthasintha, ndi kusinthasintha zimapangitsa kuti kuphunzira mafunde a mawu kukhale kopindulitsa ndipo kumathandizira ntchito zosiyanasiyana muukadaulo, zamankhwala, mafakitale, ndi kulumikizana. Pomvetsetsa lingaliro la mafunde a mawu, titha kufotokoza zochitika zosiyanasiyana zozungulira ife ndikugwiritsa ntchito mawu moyenera komanso mosamala.
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Ngati mukufuna, nditha kuwonjezera kapangidwe ka pepala lonse (chidule, kapangidwe ka mavuto, zolinga, ndemanga ya chiphunzitso, kukambirana, mapeto, ndi zolemba) ndikuzisintha kuti zigwirizane ndi msinkhu wa sukulu ya sekondale kapena koleji.
