Mitemo yaNewton yekufamba ine mitatu, inoti mutemo wekutanga waNewton, mutemo wechipiri waNewton uye mutemo wechitatu waNewton.
Mutemo wekutanga waNewton
Mutemo wekutanga waNewton unoti chinhu chega chega chiri pazororo chicharamba chakazorora kana kuti chinhu chega chega chiri kufamba mumutsara wakatwasuka nekumhanya kwakasimba chicharamba chichifamba mumutsara wakatwasuka nekumhanya kwakasimba kana simba rese riri kushanda pachinhu chacho riri zero.
Funga nezvechinhu chakakupoteredza, semuenzaniso tafura kana dombo kana chero chinhu. Tafura yakazorora icharamba yakanyarara kana ikasafambiswa kana kusapihwa simba rekunze senge simba rekusunda kana kudhonza. Saizvozvowo, zvimwe zvinhu zvakazorora. Hapana masimba anoshanda patafura kana dombo kana chimwe chinhu chakazorora here? Kune masimba anoshanda pachinhu, asi huwandu hwemasimba ese anoshanda pachinhu kana simba rese rakaenzana ne zero. Masimba anoshanda pachinhu chakazorora pamusoro penyika yakaita sePasi igravity (w) uye simba remazuva ose ( N). Nzira yekukwevera pasi yakatarisana nepakati peNyika, nzira yekukwevera pasi yakatarisana nepakati peNyika. Hukuru hwemasimba maviri aya hwakafanana asi hwakapesana munzira, saka simba rese rakaenzana ne zero.
Zvakadini nechinhu chiri kufamba chakatwasuka nekumhanya kwakasimba? Kuti tinzwisise nyaya iyi, ngatitii wakasunda chinhu, semuenzaniso chidimbu chesimbi, pamusoro pepasi. Mushure mekusundidzirwa, chidimbu chesimbi chinononoka uye chobva chamira nekuda kwesimba rekukweshana . Kuti zvidimbu zvesimbi zvifambe mberi kana kureba, unofanirwa kukwesha pamusoro pepasi nepamusoro pezvidimbu zvesimbi. Kana pasi nepamusoro pezvidimbu zvesimbi zvakapfava, zvidimbu zvesimbi zvinofamba kure. Kana pasi rakanyatsotsvedzerera uye pasina kukweshana, zvidimbu zvesimbi zvinoramba zvichifamba uye zvisingamire. Hapana simba rinoshanda pachidimbu chesimbi chiri kufamba pamusoro pepasi rakanyatsotsvedzerera here? Kune masimba anoshanda pazvidimbu zvesimbi, kureva simba rinokwevera pasi uye simba rakajairika. Masimba maviri aya anoshanda munzira yakatwasuka uye haakanganisi kufamba kwezvidimbu zvesimbi munzira yakatwasuka kana pasi rakanyatsotsvedzerera.
Mutemo Wechipiri waNewton
Mutemo weChipiri waNewton unoti kana simba remagetsi richishanda pachinhu risiri zero, chinhu chichakurumidza. Hukuru hwekumhanya hunoenderana nehukuru hwesimba remagetsi uye hunoenderana nehuremu hwechinhu. Kutungamira kwekumhanya kwakafanana nekutungamira kwesimba remagetsi.
ΣF = ma(1.2)
Tsananguro: ΣF = simba rose (kg m/s 2 ), m = huremu (kg), a = kukurumidza (m/s 2 )
Equation 1.2 ishoko remasvomhu remutemo wechipiri waNewton.
Kana hukuru hwekumhanyisa hwakaenzana ne zero (a = 0) saka equation 1.2 inoshanduka kuita equation 1.1. Saka mutemo wekutanga waNewton inyaya yakakosha yemutemo wechipiri waNewton.
Zvichibva paequation 1.2, zvakagumiswa kuti simba guru, kukurumidza kuri kukura. Kusiyana neizvi, kukura kuri kukura, kukurumidza kuri kuderera. Hukama huripo pakati pesimba, kuwanda, nekumhanya kunonzwisiswa zviri nani mushure mekuita kuyedza kwakabatana neizvi. Imwe yekuedza inogona kuitwa kuyedza kukurumidzisa chitima chinoshanduka panjanji uchishandisa kuwanda kunodonha zvakasununguka. Shandisa ticker timer kuti uone kukurumidza kwechitima.
Mutemo wechitatu waNewton
Mutemo wechitatu waNewton unoti kana chinhu 1 chikaisa simba pachinhu 2, panguva imwe chete chinhu 2 chinoshandisa simba pachinhu 1. Hukuru hwemasimba ese ari maviri hwakafanana asi divi remasimba ese ari maviri rakapesana. Simba rimwe rinonzi chiito, rimwe richinzi simba rekuita (action-reaction force).
Chiito cheF = – Kuita kweF (1.3)
Equation 1.3 ishoko remasvomhu remutemo wechitatu waNewton. Chiratidzo chekuramba chiri muequation 1.3 chinoratidza kutungamira kwesimba.
Ita bvunzo kuti unzwisise zviri nani mutemo wechitatu waNewton. Kana uine skateboard, svetedza madziro wakamira pairi. Mushure mekusvetedza madziro, skateboard inodzokera kumashure. Kusunda kwako kuri mberi, uku skateboard ichidzokera kumashure. Izvi zvinoratidza kuti madziro ari kukusundawo. Paunosvetedza madziro, panguva imwe chete, madziro ari kukusundawo. Simba rako rekusunda rinoshanda pamadziro, ukuwo simba rekusunda madziro richishanda pauri. Masimba maviri aya akaenzana pahukuru asi akasiyana munzira. Unogona kudana simba rimwe kuti chiito uye rimwe kuti chiito.
Imwe nzira yaunogona kuita ndeyekuputitsa bharumu rerabha, wozorisunungura mushure mekunge razara nemhepo. Mushure mekurisunungura, bharumu "rinobhururuka." Kufamba kwebharumu kwakatarisana nekwakaburitswa mweya kubva mubharumu. Izvi zvingatsanangurwa sei? Kana muromo webharumu waburitswa, bharumu rinosundira mweya kunze. Panguva imwe chete, mweya unosundirawo bharumu. Kusunda kwemhepo kunoita kuti bharumu ribhururuke. Kusunda kwebharumu kunoshanda mumhepo, uye kusunda kwemhepo kunoshanda pabharumu. Masimba maviri aya akaenzana muhukuru asi akasiyana munzira.
Muenzaniso wezvinetso
1. Pane zvinhu zvina, bhanana = 4 kg, bhuku = 0,8 kg, basketball = 3,5 kg, mango = 1,2 kg. Dengu rinodhonzwa nesimba re30 N panzvimbo yakatsetseka ( μ = 0,4). Kuti dengu rifambe zvakanaka (huremu hwedengu hahuna hanya), zvinhu zvinofanirwa kuiswa mudengu ndeizvi...
Kukurukurirana
Zvinozivikanwa:
Huremu hwebhanana (m 1 ) = 4 kg
Huremu hwebhuku (m2 ) = 0,8 kg
Huremu hwebhora (m3 ) = 3,5 kg
Huremu hwemango (m4 ) = 1,2 kg
Simba rekudhonza (F) = 30 N
Kukosha kwekukweshana kwakasimba ( μ s ) = 0,4
Kukurumidza kunokonzerwa negiravhiti (g) = 10 m/s 2
Usafuratira dengu guru
Simba rekukweshana rinomira (fs ) rinoshanda kana chinhu chichiri kuzorora uye chave kuda kufamba, ukuwo simba rekukweshana rinoita kana chinhu chichifamba.
Akabvunzwa: Huremu hwechinhu chacho
Mhinduro:
Dengu richafamba chaizvo kana hukuru hwesimba rekudhonza (F) = hukuru hwesimba rekukweshana risingachinji (f s ).
Verenga hukuru hwesimba rekukweshana rinomira (fs ) :
f s = μ s N = μ s w = μ s mg = (0,4)(m)(10)
fs = 4 m
Dengu chairo richafamba:
F = fs
30 = 4m
m = 30/4
m = 7,5 kg
Huremu hwebhanana 4 kg + huremu hwebhora 3,5 kg = 7,5 kg
Zvinhu zvinofanirwa kuiswa mudengu mabhanana nemabhora.
2. 2014/2015 SMA/MA Mubvunzo weNyaya yeFizikisi Nhamba 5
Zvinhu A zvine huremu hwe6 kg uye B zvine huremu hwe4 kg zvinobatanidzwa netambo uye zvinodhonzwa nesimba F = 60 N sezvakaratidzwa mumufananidzo unotevera.
Kana sisitimu iri kufamba uye coefficient yekinetic friction pakati pepasi nezvinhu zviviri iri 0,5 (tg θ = 3/4), uye g = 10 ms -2 , saka hukuru hwesimba rekumanikidzwa mutambo T inobatanidza zvinhu zviviri….
A. 28,8 N
B. 30,0 N
C. 39,6 N
D. 48,0 N
E. 50,0 N
Kukurukurirana
Zvinozivikanwa kuti:
Huremu hwechinhu A (m A ) = 6 kg
Huremu hwechinhu B (m B ) = 4 kg
Simba rekudhonza (F) = 60 Newton
Kukwana kwekukakavadzana kwekinetic pakati pechinhu nepasi (μ k ) = 0,5
Kukurumidza kunokonzerwa negiravhiti (g) = 10 m/s 2
Tangent θ = 3/4
Mubvunzo: Kumanikidzwa kuri mutambo T kwakakura sei ?
Mhinduro:
Chikamu chesimba F chakatambanuka:
F x = F cos θ
F x = (60)(4/5) = (4)(12) = 48 N
Chikamu chakamira chesimba F:
F y = F sin θ
F y = (60)(3/5) = (3)(12) = 36 N
Simba rakajairika rechinhu A:
N A = w A = m A g = (6)(10) = 60 N
Simba rakajairika rechinhu B:
N 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
Kinetic friction force pakati pechinhu A nepasi:
f kA = μ k N A = (0,5)(60) = 30 N
Simba rekukweshana kwekinetic pakati pechinhu B nepasi:
f kB = μ k N B = (0,5)(4) = 2 N
Verengai kukurumidza kwezvinhu zvese zviri zviviri:
ΣF = ma
F x – T + T – f kB – f kA = (m A + m B ) a
Simba rekumanikidza riri mutambo T rine hukuru hwakafanana pakureba kwetambo uye rine divi rakasiyana saka rinobviswa muequation.
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
Verenga simba rekumanikidzwa kwetambo T:
Funga nezvechinhu A. Masimba anoshanda pachinhu A ari munzira yakatwasuka (yakatsetseka) isimba rekumanikidzwa kwetambo (T) rinonangidzirwa kurudyi uye simba rekukweshana kinetic (f kA ) rinonangidzirwa kuruboshwe.
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
Funga nezvechinhu B. Masimba anoshanda pachinhu B ari munzira yakatwasuka (yakatsetseka) isimba F x rinonangidzirwa kurudyi, simba rekinetic friction (f kB ) uye simba retambo tension (T) rinonangidzirwa kuruboshwe.
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
Saka simba rekumanikidzwa riri mutambo rinoshanda pachinhu A (T A ) = simba rekumanikidzwa riri mutambo rinoshanda pachinhu B (T B ) = 39,6 N.
Mhinduro chaiyo ndiC.
3. 2014/2015 SMA/MA Mubvunzo weNyaya yeFizikisi Nhamba 5
Tarisa mufananidzo unotevera!
Nekuda kwesimba F, hurongwa hwezvinhu hunofamba. Kana pasi pakaoma uye coefficient ye kinetic friction pakati pemabhuroko maviri nepasi iri 0,2, chii chinoita kuti zvinhu zviviri zviwedzere kumhanya? (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
Kukurukurirana
Zvinozivikanwa kuti:
Huremu hwechinhu A (m A ) = 4 kg
Huremu hwechinhu B (m B ) = 2 kg
Simba rekudhonza (F) = 30 Newton
Kukwana kwekukakavadzana kwekinetic pakati pechinhu nepasi (μ k ) = 0,2
Kukurumidza kunokonzerwa negiravhiti (g) = 10 m/s 2
cos 37 o = 0,8
chivi 37 o = 0,6
Mubvunzo: Kukurumidzisa kupi kunoitika pazvinhu zviviri izvi?
Mhinduro:
Chikamu chesimba F chakatambanuka:
F x = F cos θ
F x = (30)(0,8) = 24 N
Chikamu chakamira chesimba F:
F y = F sin θ
F y = (30)(0,6) = 18 N
Simba rakajairika rechinhu A:
N A = w A = m A g = (4)(10) = 40 N
Simba rakajairika rechinhu B:
N 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
Kinetic friction force pakati pechinhu A nepasi:
f kA = μ k N A = (0,2)(40) = 8 N
Simba rekukweshana kwekinetic pakati pechinhu B nepasi:
f kB = μ k N B = (0,2)(2) = 0,4 N
Verengai kukurumidza kwezvinhu zvese zviri zviviri:
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
Mhinduro chaiyo ndiA.
