Boiteko le matla

Haeba o sutumelletsa buka tafoleng ho fihlela e sisinyeha, o etsa mosebetsi bukeng. Haeba ntho e oela holim'a lefatše hobane e huloa ke matla a khoheli, joale matla a khoheli a sebetsa nthong eo. Ka lehlakoreng le leng, haeba o sutumelletsa ntho ka matla a hao 'ohle ho fihlela u kolobile ke mofufutso empa ntho eo e sa sisinyehe, joale ha o so etse mosebetsi nthong eo. Bophelong ba letsatsi le letsatsi, batho ba bang ba re o entse mosebetsi kapa o sebelitse ka thata ho sutumelletsa ntho eo, empa ho ea ka fisiks , ha o so etse mosebetsi nthong eo hobane ntho eo ha e na ho falla.

Mosebetsi nthong o ka etsoa ke matla a sa fetoheng (boholo le tataiso ea matla kamehla li lula li tšoana) kapa matla a feto-fetohang (boholo le tataiso ea matla kamehla lia fetoha). Mohlala oa matla a sa fetoheng ka boholo le tataiso ke matla a khoheli a sebetsang nthong ha ntho e le haufi le bokaholimo ba Lefatše. Ha ntho e oela ka bolokolohi haufi le bokaholimo ba Lefatše, boholo le tataiso ea ho potlaka ha ho oa ha ntho ka bolokolohi lia fetoha hobane boholo le tataiso ea matla a khoheli a potlakisang ntho lia fetoha. Mohlala oa matla a sa fetoheng ka boholo (tataiso ea matla ea fetoha) ke matla a selemo . Haeba u otlolla selemo, ha bolelele ba selemo bo ntse bo eketseha, u tla se hula ka thata. Boholo ba matla a sebelisoang selemo ha bo fetohe ha selemo se otlolla. Mohlala o mong ke ha rokete e fallela sebakeng kapa e khutlela holim'a Lefatše. Ha rokete e ntse e tsamaea, boholo ba matla a khoheli a sebetsang roketeng bo fetoha ka mokhoa o fapaneng ho ea ka sekwere sa sebaka ho tloha bohareng ba Lefatše.

Ho ya ka dipalo, mosebetsi o etswang ke matla a sa fetoheng nthong o hlaloswa e le sehlahiswa sa ho falla ha matla nako kapa karolo ya matla ka lehlakoreng leo ntho e fallang ho lona.

Mosebetsi o etsoang ke matla a sa fetoheng joalo ka seliba o ke ke oa baloa ho sebelisoa mokhoa oa mosebetsi ka matla a sa fetoheng. Haeba seliba se otlolohile, ha seliba se ntse se otloloha haholoanyane, matla a ho hula a hlokahalang ho otlolla seliba le 'ona aa eketseha. Ka ho tšoanang, haeba seliba se hatelloa, ha seliba se tiile, matla a ho sututsa a hlokahalang le 'ona aa eketseha. Hafeela seliba se hatelloa kapa se otlolohile, matla a seliba a fetoha ho tloha ho 0 (x = 0) ho ea ho palo e phahameng (F = kx) kahoo matla a seliba a baloa ho sebelisoa karolelano.

Mohlala oa mathata

1. Lipotso tsa Tlhahlobo ea Naha ea 2018

Boloko ba boima ba m bo holim'a bokaholimo bo bataletseng bo boreleli. Boloko bo phomotse boemong ba (1) 'me bo huloa ka matla ke F ho ea boemong ba (2) ka nako e khuts'oane ea t joalo ka ha ho bontšitsoe setšoantšong.

Ka ho fetola boima le matla, lintlha tse latelang lia fumanoa:

Ho tsoa tafoleng e ka holimo, mosebetsi o etsoang ke lintho ho tloha ho tse kholo ho isa ho tse nyane ke…

Puisano

Hoa tsebahala:

Lebelo la pele (v _o ) = 0

O botsitse:

Karabo:

Foromo ea mosebetsi:

W = F s ………. Foromo ea 1

Foromo ea GLBB:

s = vo _o t + 1/2 ho ²

s = 1/2 ho ²

Kenya sebakeng sa foromo ea 1

W = F ( 1/2 ho ² ) ……. Foromo 2

Foromo ea matla:

F = ma

a = F / m

Kenya sebakeng sa foromo ea 2

W = 0,5 F (F/m) t ²

W = 0,5 (F ² /m) t ² ……. Foromo 3

Sebelisa foromo ea 3 ho bala boiteko.

1) W = 0,5 (F ² /m) t ² = 0,5 (3 ² /12)(4 ² ) = (0,5)(9/12)(16) = (9/12) 8 = 6

2) W = 0,5 (F ² /m) t ² = 0,5 (4 ² /16)(3 ² ) = (0,5)(16/16)(9) = (1) 4,5 = 4,5

3) W = 0,5 (F ² /m) t ² = 0,5 (5 ² /20)(2 ² ) = (0,5)(25/20)(4) = (1,25) 2 = 2,5

4) W = 0,5 (F ² /m) t ² = 0,5 (6 ² /24)(1 ² ) = (0,5)(36/24)(1) = (1,5) 0,5 = 0,75

Mosebetsi o etsoang ke lintho ho tloha ho tse kholo ho isa ho tse nyane ke 1, 2, 3, 4.

2. Lipotso tsa Tlhahlobo ea Naha ea SMA/MA ea 2017

Lebokose la boima ba 6 kg le thella ka lebelo la 8 m/s ^-1 sebakeng se sekametseng ka thata se nang le sekhutlo sa ho sekamela sa α sebakeng se bataletseng. Haeba matla a khohlano a sebetsang holim'a lebokose e le 5 N le tan α = 3/4, joale matla a F a lokelang ho sebelisoa ho emisa lebokose tlase sebakeng se sekametseng ke…

A. 15 N

B. 25 N

C. 45 N

D. 55 N

E. 69,4 N

Puisano

Hoa tsebahala hore:

Boima ba lebokose (m) = 6 kg

Ho potlaka ka lebaka la matla a khoheli (g) = 10 m/s ²

Lebelo la pele la lebokose (vo _o ) = 8 m/s

Lebelo la ho qetela la lebokose (v _t ) = 0 m/s (lebokose le tlameha ho ema pele le fihla tlase ho sefofane se sekametseng)

Matla a ho thulana (F _khohlano ) = 5 N

Tangent α = lehlakore le ka pele / lehlakore le ka tlase = 3/4

Hypotenuse = limithara tse 5

E botsitsoe: F

Karabo:

Khopolo-taba ea mosebetsi le matla a mechini:

Mosebetsi o etsoang ke matla a sa bolokeheng = phetoho ea matla a mechini

Mosebetsi o etsoang ke matla a sa bolokeheng = phetoho ea matla a kinetic le a ka bang teng.

Ho na le matla a mabeli a sa bolokeheng, e leng kinetic friction le F force.

Mosebetsi o etsoang ke matla a ho qabana a kinetic lebokoseng:

W = -(F _ges )(s) = -(5)(5) = -25

Ha e ntle hobane tataiso ea matla a khohlano e fapane le tataiso ea motsamao oa lebokose.

Mosebetsi o entsoeng ka matla F:

W = (F)(s) = (F)(5) = -5F

Hase nnete hobane tataiso ya matla F e fapane le tataiso ya motsamao wa kreite.

Phetoho ea matla a kinetic:

Δ EK = 1/2 m (v _t ² – v _o ² ) = 1/2 (6) (0 ² – 8 ² ) = (3) (0-64) = (3)(-64) = -192

Phetoho ea matla a khoheli:

Δ EP = mgh = (6)(10)(-3) = -180

h e mpe hobane boemo ba ho qetela bo ka tlase ho boemo ba pele

Khopolo-taba ea mosebetsi le matla a mechini:

W _nc = Δ EM

W _ges + W _F = Δ EP + Δ EK

-25 – 5F = -180 -192

-25 – 5F = -372

-5F = -372 + 25

-5F = – 347

F = -347 / -5

F = 69,4 Newton

Karabo e nepahetseng ke E.

3. Lipotso tsa Tlhahlobo ea Naha ea SMA/MA ea 2017

Boloko ba 10 kg bo thella tlase ho tloha ntlheng ya A ho pholletsa le B mme bo ema ntlheng ya C jwalo ka ha ho bontshitswe setshwantshong. Coefficient ya kinetic friction pakeng tsa boloko le bokahodimo bo makukuno ke 0,2, kahoo bolelele ba tsela ya ABC ke…

A. 250 cm

B. 200 cm

Bolelele ba lisenthimithara tse 150

D. 100 cm

E. 80 cm

Puisano

Hoa tsebahala hore:

Boima ba boloko (m) = 10 kg

Ho potlaka ka lebaka la matla a khoheli (g) = 10 m/s ²

Boima ba boloko (w) = mg = (10 kg)(10 m/s ² ) = 100 Newtons

Bolelele ba sefofane se sekametseng (h) = 30 cm = 0,3 metres

Bolelele ba sefofane se sekametseng = 50 cm = 0,5 metres

Koefficient ea kinetic friction ( μ _k ) = 0,2

Matla a khohlano ea kinetic (f _k ) = μ _k N = μ _k w = (0,2)(100 N) = 20 N

Potso: Bolelele ba tsela ABC

Karabo:

Nahana ka motsamao oa ntho ho tloha ntlheng ea AB.

Matla a pele a mechini ntlheng ea A = matla a khoheli a ka bang teng = mgh = (10)(10)(0,3) = (10)(3) = 30 Joules

Matla a ho qetela a mechini ntlheng ea B = matla a kinetic

Molao oa paballo ea matla a mechini:

Matla a pele a mechini = matla a ho qetela a mechini

30 Joule = Matla a Kinetic

Kahoo matla a kinetic ntlheng ea B = 30 Joules.

Nahana ka motsamao oa ntho ho tloha ntlheng ea BC.

Khopolo-taba ea matla a mosebetsi e bolela hore mosebetsi o etsoang ke matla a sa bolokeheng o lekana le phetoho ea matla a mechini a ntho. Phetoho ea matla a mechini = matla a ho qetela a mechini - matla a pele a mechini. Ka lipalo:

W _NC = Δ EM

W _NC = EM ₂ – EM ₁

Ntho ena e lutse holim'a sebaka se bataletseng hoo matla a khoheli a ka bang lefela. Matla a mechine (EM) = matla a kinetic (EK).

Matla a kinetic a pele (EK ₁ ) = matla a kinetic ntlheng ea B = 30 Joules

Matla a ho qetela a kinetic (EK ₂ ) = matla a kinetic ntlheng ea C = 0 (li-block stops).

Mosebetsi o etsoang ke matla a sa bolokeheng a BC ke mosebetsi o entsoeng ke matla a khohlano ea kinetic.

W _NC = – f _k s = – 20 s

bobo

W _NC = EK ₂ – EK ₁

– 20 s = 0 – 30

– 20 s = – 30

20 ses = 30

s = 30/20 = 3/2 = 1,5 metres = 1,5 x 100 cm = 150 cm.

Bolelele ba pina ABC = 50 cm + 150 cm = 200 cm.

Karabo e nepahetseng ke B.

4. 2014/2015 SMA/MA Fisiks Tlhahlobo ea Naha Potso ea 8

Sheba setšoantšo se latelang! Boloko bo thella sebakeng se sekametseng ka tsela e sa tsitsang se nang le coefficient ea khohlano ea 0,4. Haeba g = 10 ms ^-2 , joale lebelo la boloko ha le fihla tlase sebakeng se sekametseng ke...

A. 2√5 ms^-1

B. 2 √7 ms ^-1

C. 2 √14 ms ^-1

D. 2 √19 ms ^-1

E. 2 √23 ms ^-1

Puisano

Ha ke ntse ke shebile setšoantšo se ka tlase

Hoa tsebahala hore:

Bolelele ba pele (h _o ) = 6 m

Bolelele ba ho qetela (h _t ) = 0 m

Lebelo la pele (vo _o ) = 0 (qalong boloko bo ntse bo le teng)

Koefficient ea khohlano ea kinetic ( μ _k ) = 0,4 ( boloko e thella e le coefficient ea khohlano ea kinetic, eseng coefficient ea khohlano e sa fetoheng )

Ho potlaka ka lebaka la matla a khoheli (g) = 10 ms ^-2

cos θ = tlase/oblique = 8/10

Karolo ea boima ka lehlakoreng le otlolohileng = w _y = w cos θ = mg cos θ = m (10) (8/10) = m (10)(4/5) = m (40/5) = 8 m

Matla a tloaelehileng = N = w _y = 8 m

Matla a khohlano ea kinetic = f _k = μ _k N = μ _k w _y = (0,4)(8 m) = 3,2 m

Potso: Lebelo la ho qetela (v _t )

Karabo:

Khopolo-taba ea matla a mosebetsi e bolela hore mosebetsi o etsoang ke matla a sa bolokeng nthong o lekana le phetoho ea matla a mechini a ntho. Mohlala oa matla a sa bolokeng ke khohlano ea kinetic.

W_nc = ΔEM

W _nc = Δ EK + Δ EP

Lintlha :

W _nc = Mosebetsi o etsoang ke matla a sa bolokeheng, Δ EM = Phetoho matla a mechini, Δ EK = Phetoho matla a kinetic, Δ EP = Phetoho matla a ka bang teng.

Phetoho ea matla a kinetic:

ΔEK = 1/2 m (v_t² - v_o²) = 1/2 m (v_t² - 0) = 1/2 mv_t²

Phetoho ea matla a ka bang teng:

Δ EP = mg (h _t – ho ₎ = m (10)(0-6) = m (10)(-6) = – 60 m

Mosebetsi o etsoang ka ho qabana ha kinetic:

Wnc = – f _ks = – ( 3,2 m)(10) = – 32 m

Ke ntho e mpe hobane matla a ho qabana a kinetic a etsa mosebetsi o mpe, moo tataiso ea matla a ho qabana a kinetic (ho ea holimo) e fapaneng le tataiso ea ho falla ha ntho (ho ea tlase).

Bala lebelo la ho qetela (v _t ):

Wnc = Δ EK + Δ EP

– 32 m = 1/2 mv _t ² – 60 m

– 32 m = m (1/2 v _t ² – 60)

– 32 = 1/2 v _t ² – 60

– 32 + 60 = 1/2 v _t ²

28 = 1/2 v _t ²

2 (28) = v _t ²

56 = v _t ²

v _t = √4.14

v _t = 2 √14 ms ^-1

Karabo e nepahetseng ke C.

5. Potso ea Tlhahlobo ea Naha ea Fisiks ea SMA/MA ea 2014/2015 Nomoro ea 8

Sheba setšoantšo se ka thoko!

Boloko bo thella tlase sefofaneng se sekametseng ka thata, bo fihla leotong la sefofane se sekametseng ka lebelo la 10 ms ^-1 . Haeba matla a khohlano a sebetsang e le 2 N le g = 10 ms ^-2 , joale boleng ba h ke ….

A. 10 m

B. 8 m

C. 6 m

D. 4 m

E. 2 m

Puisano

Hoa tsebahala hore:

Boima ba boloko (m) = 1 kg

Lebelo la pele (vo _o ) = 0 (qalong boloko bo ntse bo le teng)

Lebelo la ho qetela (v _t ) = 10 ms ^-1

Bolelele ba pele (h _o ) = h

Bolelele ba ho qetela (h _t ) = 0

Matla a khohlano ea kinetic (f _k ) = 2 N

Ho potlaka ka lebaka la matla a khoheli (g) = 10 ms ^-2

E botsitsoe: Bolelele (h)

Karabo:

Mosebetsi o etsoang ka ho qabana ha kinetic:

Wnc = – f _ks = – (2 )(15) = – 30

Ke ntho e mpe hobane matla a ho qabana a kinetic a etsa mosebetsi o mpe, moo tataiso ea matla a ho qabana a kinetic (ho ea holimo) e fapaneng le tataiso ea ho falla ha ntho (ho ea tlase).

Phetoho ea matla a kinetic:

ΔEK = 1/2 m (v_t² - v_o²) = 1/2 (1)(10² - 0) = 1/2 (10²) = 1/2 (100= 50

Phetoho ea matla a ka bang teng:

Δ EP = mg (h _t – ho ₎ = (1)(10)(0-h) = (10)(-h) = -10 h

Foromo ea khopolo-taba ea mosebetsi le matla a mechini:

Wnc = Δ EK + Δ EP

– 30 = 50 – 10 dihora

Lihora tse 10 = 50 + 30

Lihora tse 10 = 80

h = 80/10

h = limithara tse 8

Karabo e nepahetseng ke B.