Mehlala ea lipotso mabapi le Matla a Mechanical

Mehlala e 6 ea Lipotso tsa Matla a Mekaniki

Theorem ea mosebetsi le matla a mechini

1. Ela hloko setšoantšo ho falla thibela ka tsela e latelang! Nka hore g = 10 m/s²Haeba coefficient ea khohlano ea kinetic pakeng tsa boloko le fatše μk = 0,5, joale boleng ba ho falla ha ntho ke ….

A. 5,00 m

B. 4,25 m

C. 3,00 m

D. 2,50 m

E. 2,00 m

Puisano

Hoa tsebahala :

Khokahano ea kinetic ea khohlano (μk) = 0,5

Boima ba boloko (m) = 4 kg

Ho potlaka ka lebaka la matla a khoheli (g) = 10 m/s²

Boima ba boloko (w) = mg = (4)(10) = 40 Newton

Haeba boloko bo le holim'a sebaka se bataletseng, joale matla a tloaelehileng (N) = boima (w) = 40 Newtons.

Lebelo la pele (v)₁) = 5 m/s

Lebelo la ho qetela (v)₂) = 0 m/s

E botsitsoe : ho falla ha ntho (lintho)?

Jawab :

Teori ea matla a mosebetsi le mechine e bolela hore mosebetsi (W) o etsoang ke matla a sa bolokeheng o lekana le phetoho ea matla a mechini a ntho kapa matla a ho qetela a mechini (EM).₂) – matla a pele a mechini (EM)₁Khohlano ea Kinetic ke matla a sa bolokeng 'me matla a le mong feela a sa bolokeng a sebetsang holim'a block ke khohlano ea kinetic.

W= ΔEM

f_k s = EM₂ – EM₁

Mosebetsi o etsoang ka ho qabana ha kinetic:

W = f_k s = (μk)(N)(s) = (0,5)(40)(s) = 20 s

Liphetoho matla a mechini:

ΔEM = EM₂ – EM₁ = (EK + EP)₂ – (EK + EP)₁

Lintho li tsamaea holim'a sebaka se bataletseng 'me ha li bone liphetoho bophahamong (Δh = 0) kahoo ha ho na phetoho matla a khoheli (ΔEP = EP₂ – EP₁ = 0). Kahoo phetoho ea matla a mechini e kenyelletsa feela phetoho ea matla a kinetic.

ΔEM = EK₂ – EK₁ = ½ mv₂² – ½ mv₁² = ½ m (v₂² - v₁²)

ΔEM = ½ (4)(0² - 5²) = (2)(25) = 50

Ho falla ha boloko ke:

W= ΔEM

20 ses = 50

s = 50 / 20 = limithara tse 2,5

Karabo e nepahetseng ke D.

Molao oa paballo ea matla a mechini

2. Lintho tsa A le B li na le boima bo lekanang. Ntho ea A e oa ho tloha bophahamong ba limithara tsa h 'me B e oa ho tloha ho limithara tsa lihora tse 2. Haeba A e otla fatše ka lebelo la vm/s, joale ntho ea B e tla otla fatše ka matla a kinetic a….

A. 2 mv²

B. mv²

C. 3/4 mv²

D. 1/2 mv²

E. 1/4 mv²

Puisano

Lebelo la ho qetela la ntho B le oelang ka bolokolohi ho tloha bophahamong ba lihora tse 2 ke:

v² = 2 g (lihora tse 2) = 4 gh

Matla a kinetic a ntho B ke:

EK_B = ½ mv² = ½ m (4 gh) = 2 mgh —– Tekanyo 1

Matla a pele a mechini a ntho B ke matla a khoheli a ka bang teng = mg h. Matla a ho qetela a mechini a ntho B ke matla a kinetic = ½ mv².

Molao oa paballo ea matla a mechini :

mgh = ½ mv².

Hobane mgh = ½ mv² ebe re ka nkela mgh sebaka ho equation ea 1 ka ½ mv².

Matla a kinetic a ntho B = 2 mgh = 2(½ mv)²) = mv²

Karabo e nepahetseng ke B.

3. Sheba setšoantšo se ka tlase! Ntho e oela ka bolokolohi ho tloha bophahamong ba limithara tse 20. Haeba lebelo le bakoang ke matla a khoheli e le 10 m/s, joale lebelo la ntho ha e le limithara tse 15 ka holim'a lefatše ke….

A. 2 m/s

B. 5 m/s

C. 10 m/s

D. 15 m/s

E. 20 m/s

Puisano

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

Matla a kinetic a ntho ntlheng ea 2 = phokotso ea matla a khoheli ka limithara tse 5

½ mv² = mgh

½ v² = (10)(20-15)

½ v² = (10)(5)

½ v² = 50

v² = (2)(50)

v² = 100

v = 10 m/s

Karabo e nepahetseng ke C.

4. Boloko bo tshwerwe ka hodimo ho sefofane se sekametseng jwalo ka ha ho bontshitswe setshwantshong. Ha e lokollwa, boloko bo thella ntle le ho kgohlana hodima moedi. Lebelo la boloko ha le fihla tlase ho moedi ke…

A. 6 ms^-1

B. 8 ms^-1

C. 10 ms^-1

D. 12 ms^-1

E. 16 ms^-1

Puisano

Matla a pele a mechini = matla a khoheli a ka bang teng = mgh = m (10)(5) = 50 m

Matla a ho qetela a mechini = matla a kinetic = 1/2 mv²

Molao oa paballo ea matla a mechini o bolela hore matla a pele a mechini = matla a ho qetela a mechini.

EM_o = EM_t

50 m = 1/2 mv²

50 = halofo ea v²

2 (50) = v²

100 = v²

v = 10 m/s

Karabo e nepahetseng ke C.

5. Boloko bo nang le boima ba m kg bo lokollwa ho tloha bophahamong ba limithara tse h ka hodima lefatshe jwalo ka ha ho bontshitswe setshwantshong. Karolelano ya matla a ka bang teng (EP) le matla a kinetic (EK) ha e le ntlheng ya M ke….

K. 1: 3

B. 1: 2

C. 2: 1

D. 2: 5

E. 3: 7

Puisano

Matla a khoheli a ka bang teng ntlheng ea M:

EP_M = mg (lihora tse 0,3)

Matla a kinetic ntlheng ea M = phokotso ea matla a khoheli ka h-0,3h = 0,7h

EK_M = EP = mg (lihora tse 0,7)

Karolelano ea matla a khoheli le matla a kinetic ntlheng ea M ke:

EP_M : EK_M

mg (lihora tse 0,3): mg (lihora tse 0,7)

0,3: 0,7

3: 7

Karabo e nepahetseng ke E.

6. Sheba setšoantšo sa ntho A e oelang ka bolokolohi ho tloha ntlheng ea P ka tlase!

Haeba EP_Q le EK_Q e 'ngoe le e 'ngoe ke matla a ka bang teng le matla a kinetic ntlheng ea Q (g = 10 m/s²), ebe EP_Q : EK_Q ke….

K. 16: 9

B. 9: 16

C. 3: 2

D. 2: 3

E. 2: 1

Puisano

Matla a khoheli a ka bang teng ntlheng ea Q:

EP_Q = mgh = (m)(10)(1,8) = 18 m

Matla a kinetic ntlheng ea Q = phokotso ea matla a khoheli ka 5-1,8 = limithara tse 3,2

EK_Q = EP = mgh = m (10)(3,2) = 32 m

Karolelano ea matla a khoheli le matla a kinetic ntlheng ea Q ke:

EP_Q : EK_Q

18 m : 32 m

18: 32

9: 16

Mohloli oa lipotso:

Lipotso tsa Fisiks tsa Tlhahlobo ea Naha bakeng sa Sekolo se Phahameng sa Thuto e Phahameng/Sekolo se Phahameng sa Mosebetsi