Mfundo ya mphamvu ya ntchito ndi makina
Chiphunzitso cha mphamvu ya ntchito-kinetic chimanena kuti ntchito ya neti kapena ntchito yochitidwa ndi mphamvu ya neti ndi yofanana ndi kusintha kwa mphamvu ya kinetic.
W net = TO t – TO o = 1⁄2 m(v t 2 – vo 2 )
W net = Pali mitundu iwiri ya mphamvu, yomwe ndi mphamvu yosunga malamulo, ndi mphamvu yosasunga malamulo. Chifukwa chake, ntchito ya ukonde ingaganizidwe kuti ikuphatikizapo ntchito yochitidwa ndi mphamvu yosunga malamulo ndi ntchito yochitidwa ndi mphamvu yosasunga malamulo.
W c + W nc = ΔKE
Ntchito yochitidwa ndi mphamvu yosunga malamulo ndi yofanana ndi kusintha koipa kwa mphamvu zomwe zingatheke:
W c = -ΔPE
– ΔPE + W nc = ΔKE
W nc = ΔPE + ΔKE
Wnc = ΔME
Equation yomwe ili pamwambapa imati ntchito yomwe yachitika ndi mphamvu yosasintha pa chinthu ndi yofanana ndi kusintha kwa mphamvu ya makina ya chinthucho. Mphamvu ya makina = mphamvu yothekera + mphamvu ya kinetic. Mphamvu yothekera ingatenge mawonekedwe a mphamvu yokoka kapena mphamvu yokhazikika.
Funso la chitsanzo: Chiphunzitso cha mphamvu ya ntchito ndi makina
Bokosi la 2 kg limayamba kuyenda pa liwiro la 10 m/s. Patapita nthawi yochepa, bokosilo limaima. Kuchuluka kwa kugwedezeka kwa kinetic pakati pa bokosi ndi pansi ndi 0.2. Kuthamanga kwa mphamvu yokoka ndi 10 m/s 2. Kodi kusuntha kwa bokosilo ndi kotani?
Zokambirana:
Kuzindikiritsidwa: m = 2 kg, v o = 10 m/s, vt = 0, k = 0.2, w = mg = (1 kg)(10 m/s 2 ) = 10 kg m/s 2 = 10 Newtons,
Kufunsidwa: kuchuluka kwa kusamuka kwa bokosi (s)
Chiphunzitso cha mphamvu ya ntchito ndi makina:
W nc = ΔME
W nc = ΔPE + ΔKE
Kutalika (h) kumakhalabe kosasintha kapena palibe kusintha kwa kutalika, kotero palibe kusintha kwa mphamvu yokoka.
Wnc = ΔKE
Ntchito yochitidwa ndi mphamvu ya kinetic frictional ndi iyi:
W nc = – f k s = μ k N -s = μ k w -s = μ k mg -s
W nc = – (0.2)(2)(10)(s) = – (4)(s)
Mphamvu ya kinetic frictional imagwira ntchito yoipa (mphamvu ya kinetic frictional ili mbali yosiyana ndi kusamuka kwa chinthucho)
Kusintha kwa mphamvu ya kinetic:
ΔKE = 1⁄2 m (v t 2 – vo 2 ) = 1⁄2 (2)(0 2 – 10 2 ) = (0 – 100) = – 100
Kusamutsa kwa chinthu:
W nc = ΔKE
– (4)(s) = – 100
s = – 100 / – 4 = mamita 25
Mafunso ndi mayankho 20 okhudza mfundo ya mphamvu ya ntchito ndi makina:
1. Funso: Kodi mfundo ya mphamvu ya ntchito ndi makina ndi iti? Yankho: Mfundo ya mphamvu ya ntchito ndi makina imati ntchito yochitidwa pa chinthu ndi yofanana ndi kusintha kwa mphamvu yake ya makina.
2. Funso: Kodi ntchito imafotokozedwa bwanji mu fizikisi? Yankho: Ntchito imafotokozedwa ngati chinthu chomwe chimachokera ku mphamvu yomwe imagwiritsidwa ntchito pa chinthu ndi mtunda womwe imayenda molunjika ku mphamvuyo
3. Funso: Kodi mphamvu ya makina ndi chiyani? Yankho: Mphamvu ya makina imakhala ndi mphamvu ya kayendedwe ka chinthu ndi mphamvu yomwe ingatheke.
4. Funso: Ngati palibe mphamvu zosasintha, kodi tinganene chiyani za mphamvu yonse ya makina ya dongosolo lotsekedwa? Yankho: Mphamvu yonse ya makina imakhalabe yofanana.
5. Funso: Perekani chitsanzo cha mphamvu yosunga zinthu mwadongosolo. Yankho: Mphamvu yokoka ndi chitsanzo cha mphamvu yosunga zinthu mwadongosolo.
6. Funso: Kodi mphamvu yamagetsi imasiyana bwanji ndi mphamvu yamagetsi? Yankho: Mphamvu yamagetsi ndi mphamvu yomwe imabwera chifukwa cha malo, monga kutalika pamwamba pa nthaka, pomwe mphamvu yamagetsi imabwera chifukwa cha kuyenda.
7. Funso: Kodi ntchito yochitidwa ndi mphamvu yosunga zinthu zakale imakhudzana bwanji ndi mphamvu zomwe zingatheke? Yankho: Ntchito yochitidwa ndi mphamvu yosunga zinthu zakale ndi yofanana ndi kusintha koipa kwa mphamvu zomwe zingatheke.
9. Funso: Kodi mfundo ya mphamvu yogwirira ntchito ndi makina imafotokoza bwanji kusintha kwa mphamvu yokhoza kukhala mphamvu ya kinetic mu chinthu chomwe chimagwa mwachangu? Yankho: Chinthu chikagwa, mphamvu yake yokhoza imachepa ndipo mphamvu yake ya kinetic imawonjezeka ndi kuchuluka kofanana, zomwe zimapangitsa kuti mphamvu yonse ya makina ikhale yofanana.
10. Funso: Kodi chimachitika ndi chiyani ku mphamvu ya makina ya dongosolo pamene mphamvu zosasunga chilengedwe, monga kukangana, zikugwira ntchito pa izo? Yankho: Mphamvu ya makina imachepa chifukwa mphamvu zosasunga chilengedwe zimataya mphamvu, nthawi zambiri ngati kutentha.
11. Funso: Kodi mphamvu ya makina ya dongosolo ingawonjezeke? Yankho: Inde, ntchito yakunja ikachitika pa dongosolo.
12. Funso: Kodi lingaliro la ntchito likugwirizana bwanji ndi mphamvu? Yankho: Ntchito ndi njira yomwe mphamvu imasamutsidwira kapena kusinthidwa mu dongosolo.
13. Funso: Ngati chinthu chikuyenda pa liwiro losasinthasintha, kodi tinganene chiyani za ntchito ya ukonde yomwe yachitika pa icho? Yankho: Ntchito ya ukonde yomwe yachitika pa icho ndi zero chifukwa palibe kuthamanga komwe kukuchitika.
15. Funso: N’chifukwa chiyani kasupe wopanikizika ali ndi mphamvu? Yankho: Kasupe akapanikizika, ntchito imachitika, yomwe imasungidwa ngati mphamvu yowonjezereka. Mphamvu imeneyi imatha kutulutsidwa kasupe akatulutsidwa.
16. Funso: Kodi chiphunzitso cha mphamvu ya ntchito ndi chiyani? Yankho: Chiphunzitso cha mphamvu ya ntchito chimanena kuti ntchito yochitidwa pa chinthu ndi yofanana ndi kusintha kwa mphamvu yake ya kinetic.
17. Funso: Kodi mphamvu imakhudzana bwanji ndi ntchito? Yankho: Mphamvu ndi liwiro limene ntchito imagwiridwa kapena mphamvu imasamutsidwa. Imawerengedwa ngati , pomwe ndi ntchito ndipo ndi nthawi.
18. Funso: Kodi ntchito ingakhale ndi phindu loipa? Yankho: Inde, ntchito imakhala yoipa pamene mphamvu ndi njira yoyendera zili zosiyana.
19. Funso: Ngati ngodya pakati pa mphamvu ndi njira yoyendera ndi madigiri 90, kodi ntchitoyo yachitika ndi yotani? Yankho: Ntchito yochitidwa ndi zero chifukwa mphamvuyo ilibe gawo lolowera komwe kuyenda kuli.
20. Funso: Kodi makina osavuta, monga chogwirira ntchito, amathandiza bwanji ntchito kukhala yosavuta? Yankho: Chogwirira ntchito sichisintha ntchito yonse yomwe yachitika koma chimasintha momwe mphamvu imagwiritsidwira ntchito, zomwe zimapangitsa kuti ntchitoyo ikhale yosavuta kuyendetsa bwino kapena yogwira ntchito bwino.
Lingaliro la ntchito ndi mfundo ya mphamvu ya makina ndizofunikira kwambiri mu fizikisi ndipo zimapereka kumvetsetsa koyambira kwa momwe mphamvu imasamutsidwira ndikusinthidwa m'machitidwe osiyanasiyana.
