Melao ea Newton ea motsamao e na le tse tharo, e leng molao oa pele oa Newton, molao oa bobeli oa Newton le molao oa boraro oa Newton.
Molao oa Pele oa Newton
Molao oa Pele oa Newton o bolela hore ntho e 'ngoe le e 'ngoe e phomotseng e tla lula e phomotse kapa ntho e 'ngoe le e 'ngoe e tsamaeang ka mola o otlolohileng ka lebelo le sa fetoheng e tla tsoela pele ho tsamaea ka mola o otlolohileng ka lebelo le sa fetoheng haeba matla 'ohle a sebetsang nthong eo e le lefela.
Nahana ka ntho e u potileng, mohlala, tafole kapa lefika kapa ntho efe kapa efe. Tafole e phomotseng e tla lula e phomotse haeba e sa sisinyehe kapa e sa fuoe matla a kantle joalo ka matla a ho sututsa kapa a ho hula. Ka mokhoa o ts'oanang, lintho tse ling tse phomotseng. Na ha ho na matla a sebetsang tafoleng kapa lefikeng kapa nthong efe kapa efe e phomotseng? Ho na le matla a sebetsang nthong eo, empa kakaretso ea matla 'ohle a sebetsang nthong eo kapa matla 'ohle a lekana le lefela. Matla a sebetsang nthong e phomotseng holim'a polanete e kang Lefatše ke matla a khoheli (w) le matla a tloaelehileng (N). Tsela ea matla a khoheli e otlolohile bohareng ba Lefatše, ha tsela ea matla a tloaelehileng e otlolohile bohareng. Boholo ba matla ana a mabeli boa tšoana empa bo fapane ka tsela e fapaneng, ka hona matla 'ohle a lekana le lefela.
Ho thoe'ng ka ntho e tsamaeang ka mola o otlolohileng ka lebelo le sa fetoheng? Ho hlakisa bothata bona, a re re u sutumelletsa ntho, mohlala, karolo ea tšepe, holim'a bokaholimo ba mokatong. Kamora ho sutumelletsoa, karolo ea tšepe ea lieha ebe ea ema ka lebaka la matla a khohlano . E le hore likarolo tsa tšepe li tsamaee hole kapa ho feta, u tlameha ho boreleli bokaholimo ba mokatong le bokaholimo ba likarolo tsa tšepe. Ha bokaholimo ba mokatong le bokaholimo ba likarolo tsa tšepe bo boreleli, likarolo tsa tšepe li tsamaea hole. Haeba bokaholimo ba mokatong bo boreleli ka ho phethahetseng 'me ho se na khohlano, likotoana tsa tšepe li tla tsoela pele ho tsamaea' me li se ke tsa ema. Na ha ho na matla a sebetsang holim'a karolo ea tšepe e tsamaeang holim'a bokaholimo ba mokatong bo boreleli ka ho phethahetseng? Ho na le matla a sebetsang holim'a likotoana tsa tšepe, e leng matla a khoheli le matla a tloaelehileng. Matla ana a mabeli a sebetsa ka lehlakoreng le otlolohileng 'me ha a ame motsamao oa likarolo tsa tšepe ka lehlakoreng le otlolohileng haeba mokatong o boreleli ka ho feletseng.
Molao oa Bobeli oa Newton
Molao oa Bobeli oa Newton o re haeba matla a letlooa a sebetsang nthong e se lefela, ntho e tla potlaka. Boholo ba potlaka bo lekana le boholo ba matla a letlooa 'me bo lekana le boima ba ntho ka tsela e fapaneng. Tsela eo potlaka e tsamaeang ka eona e tšoana le tsela eo matla a letlooa a tsamaeang ka eona.
ΣF = ma(1.2)
Tlhaloso: ΣF = matla ohle (kg m/s 2 ), m = boima (kg), a = ho potlaka (m/s 2 )
Tekanyo ea 1.2 ke polelo ea lipalo ea molao oa bobeli oa Newton.
Haeba boholo ba ho potlaka bo lekana le lefela (a = 0) joale equation 1.2 e fetoha equation 1.1. Kahoo molao oa pele oa Newton ke nyeoe e ikhethang ea molao oa bobeli oa Newton.
Ho latela equation 1.2, ho fihletswe qeto ya hore ha matla a le maholo, lebelo le eketseha. Ka lehlakoreng le leng, ha boima bo le boholo, lebelo le fokotseha. Kamano pakeng tsa matla, boima le lebelo e utlwisiseha hamolemo kamora ho etsa diteko tse amanang le sena. Teko e nngwe e ka etswang ke teko ya ho potlakisa terene e matla hodima diterene ho sebediswa boima bo welang ka bolokolohi. Sebedisa ticker timer ho fumana lebelo la terene.
Molao oa Boraro oa Newton
Molao oa boraro oa Newton o re haeba ntho ea 1 e sebelisa matla nthong ea 2, joale ntho ea 2 e sebelisa matla nthong ea 1. Boholo ba matla ka bobeli boa tšoana empa tataiso ea matla ka bobeli e fapane. Matla a mang a bitsoa ketso, matla a mang a bitsoa karabelo (matla a ketso-karabelo).
Ketso ea F = – Karabelo ea F (1.3)
Tekanyo ea 1.3 ke polelo ea lipalo ea molao oa boraro oa Newton. Letšoao le fosahetseng ho equation ea 1.3 le bontša tataiso ea matla.
Etsa teko ho utloisisa molao oa boraro oa Newton hamolemo. Haeba u na le skateboard, sutumelletsa leboteng ha u eme ho lona. Kamora ho sutumelletsa leboteng, skateboard e khutlela morao. Sututsa ea hau e ea pele, ha skateboard e khutlela morao. Sena se bontša hore lebota le lona lea sutumelletsa khahlanong le uena. Ha u sutumelletsa leboteng, ka nako e ts'oanang, lebota le lona lea sutumelletsa khahlanong le uena. Matla a hau a sutumelletsang a sebetsa leboteng, ha matla a sutumelletsang a lebota a sebetsa ho uena. Matla a mabeli a lekana ka boholo empa a fapane ka lehlakoreng. U ka bitsa matla a mang ketso 'me a mang karabelo.
Teko e 'ngoe eo u ka e etsang ke ho phatlola balune ea rabara, ebe u e lokolla ka mor'a hore e ruruhe 'me e tlale moea. Ka mor'a ho e lokolla, balune e "fofa." Tsela eo balune e tsamaeang ka eona e fapane le tsela eo moea o tsoang balune ka eona. Sena se ka hlalosoa joang? Ha molomo oa balune o lokolloa, balune e sutumelletsa moea kantle. Ka nako e ts'oanang, moea le oona o sutumelletsa balune. Ho sutumelletsa ha moea ho etsa hore balune e fofe. Ho sutumelletsa ha balune ho sebetsa moeeng, 'me ho sutumelletsa ha moea ho sebetsa balune. Matla a mabeli a lekana ka boholo empa a fapane ka tsela e fapaneng.
Mohlala oa mathata
1. Ho na le dintho tse 4, banana = 4 kg, buka = 0,8 kg, basketball = 3,5 kg, mango = 1,2 kg. Seroto se hulwa ka matla a 30 N hodima sebaka se bataletseng se bataletseng ( μ = 0,4). E le hore seroto se tsamaye hantle (boima ba seroto bo hlokomolohuwa), dintho tse lokelang ho kenngwa ka serotong ke...
Puisano
Hoa tsebahala:
Boima ba banana (m 1 ) = 4 kg
Boima ba buka (m2 ) = 0,8 kg
Boima ba bolo (m 3 ) = 3,5 kg
Boima ba mango (m 4 ) = 1,2 kg
Matla a ho tsikinyeha (F) = 30 N
Koefficient ea khohlano e sa fetoheng ( μs ) = 0,4
Ho potlaka ka lebaka la matla a khoheli (g) = 10 m/s 2
Hlokomoloha boima ba baskete
Matla a khohlano a sa fetoheng (fs ) a sebetsa ha ntho e ntse e phomotse mme e le mothating oa ho tsamaea, ha matla a khohlano a kinetic a sebetsa ha ntho e tsamaea.
Botsitswe: Boima ba ntho eo
Karabo:
Seroto se tla tsamaya hantle ha boholo ba matla a hulang (F) = boholo ba matla a khohlano a sa fetoheng (f s ).
Bala boholo ba matla a khohlano a sa fetoheng (fs ) :
f s = μ s N = μ s w = μ s mg = (0,4)(m)(10)
fs = 4 m
Seroto se nepahetseng se tla sisinyeha:
F = fs
30 = 4 m
m = 30/4
m = 7,5 kg
Boima ba banana 4 kg + boima ba bolo 3,5 kg = 7,5 kg
Lintho tse lokelang ho kenngoa ka basketeng ke libanana le libolo.
2. 2014/2015 SMA/MA Fisiks Tlhahlobo ea Naha Potso ea 5
Lintho tsa A tse boima ba 6 kg le B tse boima ba 4 kg li hokahantsoe ka thapo 'me li huloa ka matla F = 60 N joalo ka ha ho bontšitsoe setšoantšong se latelang.
Haeba sistimi e ntse e tsamaya mme coefficient ya kinetic friction pakeng tsa bokaholimo ba mokatong le dintho tse pedi e le 0,5 (tg θ = 3/4), le g = 10 ms -2 , jwale boholo ba matla a kgatello thapong T e hokahanyang dintho tse pedi ke….
A. 28,8 N
B. 30,0 N
C. 39,6 N
D. 48,0 N
E. 50,0 N
Puisano
Hoa tsebahala hore:
Boima ba ntho A (m A ) = 6 kg
Boima ba ntho B (m B ) = 4 kg
Matla a ho thapolla (F) = 60 Newton
Coefficient ea khohlano ea kinetic pakeng tsa ntho le fatše (μ k ) = 0,5
Ho potlaka ka lebaka la matla a khoheli (g) = 10 m/s 2
Tangent θ = 3/4
Potso: Kgatelelo e kgolo hakae thapong ya T?
Karabo:
Karolo e otlolohileng ea matla F:
F x = F cos θ
F x = (60)(4/5) = (4)(12) = 48 N
Karolo e otlolohileng ea matla F:
F y = F sin θ
F y = (60)(3/5) = (3)(12) = 36 N
Matla a tloaelehileng a ntho A:
N A = w A = m A g = (6)(10) = 60 N
Matla a tloaelehileng a ntho B:
Nomoro ea B + F y – w B = 0
N B + F y = w B
N B = w B – F y = m B g – F y = (4)(10) – 36 = 40 – 36 = 4 N
Matla a khohlano a kinetic pakeng tsa ntho A le fatše:
f kA = μ k N A = (0,5)(60) = 30 N
Matla a khohlano a kinetic pakeng tsa ntho B le fatše:
f kB = μ k N B = (0,5) (4) = 2 N
Bala lebelo la lintho ka bobeli:
ΣF = ma
F x – T + T – f kB – f kA = (m A + m B ) a
Matla a kgatello khoeleng ya T a na le boholo bo lekanang le bolelele ba khoele mme a na le lehlakore le fapaneng kahoo a tloswa ho equation.
F x – f kB – f kA = (m A + m B ) a
48 – 2 – 30 = (6 + 4) a
16 = 10 a
a = 16/10
a = 1,6 m/s 2
Bala matla a kgatello ya thapo T:
Nahana ka ntho A. Matla a sebetsang nthong A ka lehlakoreng le otlolohileng (le otlolohileng) ke matla a khatello ea thapo (T) a lebisitsoeng ka ho le letona le matla a khohlano ea kinetic (f kA ) a lebisitsoeng ka ho le letšehali.
ΣF = ma
T A – f kA = m A a
T A – 30 = (6)(1,6)
T A – 30 = 9,6
TA = 9,6 + 30 = 39,6 N
Nahana ka ntho B. Matla a sebetsang nthong B ka lehlakoreng le otlolohileng (le otlolohileng) ke matla F x a lebisitsweng ka ho le letona, matla a kinetic friction (f kB ) le matla a thapo ya kgatello (T) a lebisitsweng ka ho le letshehadi.
ΣF = ma
F x – f kB – T B = m B a
48 – 2 – T B = (4)(1,6)
46 – T B = 6,4
46 – 6,4 = T B
T B = 39,6 N
Kahoo matla a kgatello thapong a sebetsang hodima ntho A (T A ) = matla a kgatello thapong a sebetsang hodima ntho B (T B ) = 39,6 N.
Karabo e nepahetseng ke C.
3. Potso ea Tlhahlobo ea Naha ea Fisiks ea SMA/MA ea 2014/2015 Nomoro ea 5
Sheba setšoantšo se latelang!
Ka lebaka la matla a F, tsamaiso ea lintho ea sisinyeha. Haeba fatše le le thata 'me coefficient ea kinetic friction pakeng tsa li-block tse peli le fatše e le 0,2, lebelo leo lintho tse peli li le fumanang ke lefe? (cos 37 o = 0,8 , sin 37 o = 0,6)
A. 2,6 ms-2
B. 4,0 ms -2
C. 5,2 ms -2
D. 7,8 ms -2
E. 10,2 ms -2
Puisano
Hoa tsebahala hore:
Boima ba ntho A (m A ) = 4 kg
Boima ba ntho B (m B ) = 2 kg
Matla a ho thapolla (F) = 30 Newton
Coefficient ea khohlano ea kinetic pakeng tsa ntho le fatše (μ k ) = 0,2
Ho potlaka ka lebaka la matla a khoheli (g) = 10 m/s 2
cos 37 o = 0,8
sebe 37 o = 0,6
Potso: Ke lebelo lefe leo lintho tsena tse peli li le fumanang?
Karabo:
Karolo e otlolohileng ea matla F:
F x = F cos θ
F x = (30)(0,8) = 24 N
Karolo e otlolohileng ea matla F:
F y = F sin θ
F y = (30)(0,6) = 18 N
Matla a tloaelehileng a ntho A:
N A = w A = m A g = (4)(10) = 40 N
Matla a tloaelehileng a ntho B:
Nomoro ea B + F y – w B = 0
N B + F y = w B
N B = w B – F y = m B g – F y = (2)(10) – 18 = 20 – 18 = 2 N
Matla a khohlano a kinetic pakeng tsa ntho A le fatše:
f kA = μ k N A = (0,2)(40) = 8 N
Matla a khohlano a kinetic pakeng tsa ntho B le fatše:
f kB = μ k N B = (0,2) (2) = 0,4 N
Bala lebelo la lintho ka bobeli:
ΣF = ma
F x – f kB – f kA = (m A + m B ) a
24 – 0,4 – 8 = (4 + 2) a
15,6 = 6 a
a = 15,6/6
a = 2,6 m/s 2
Karabo e nepahetseng ke A.
