Kev ua haujlwm ntawm cov kua dej - teeb meem thiab kev daws teeb meem

Kev Ua Haujlwm ntawm Cov Kua Dej - Cov Teeb Meem thiab Kev daws teeb meem

1. Ib lub thawv puv dej thiab muaj ib lub qhov , raws li pom hauv daim duab hauv qab no. Yog tias qhov kev nrawm vim lub ntiajteb txawj nqus yog 10 ms ^-2 , qhov ceev ntawm dej hla lub qhov ntawd yog dab tsi?

Paub: Kev ua haujlwm ntawm cov kua dej - teeb meem thiab kev daws teeb meem 1

Qhov siab (h) = 85 cm – 40 cm = 45 cm = 0.45 meters

Kev nrawm vim lub ntiajteb txawj nqus (g) = 10 m/s ²

Xav tau: Qhov ceev ntawm dej (v)

Tshuaj:

Torricelli txoj kev xav hais tias cov dej tawm hauv lub qhov nrog tib qhov ceev li ib yam khoom poob dawb los ntawm tib qhov siab. Qhov siab (h) = 85 cm - 40 cm = 45 cm = 0.45 meters

Qhov ceev ntawm dej yog xam los ntawm kev siv cov qauv ntawm kev txav mus los dawb :

v _t² = 2 gh

v _t² = 2 gh = 2(10)(0.45) = 9

v _t = √9 = 3 m/s

2. Ib lub thawv puv dej thiab muaj ib lub qhov, raws li pom hauv daim duab hauv qab no. Yog tias qhov kev nrawm vim lub ntiajteb txawj nqus yog 10 ms ^-2 , qhov ceev ntawm dej hla lub qhov ntawd yog dab tsi.

Paub: Kev ua haujlwm ntawm cov kua dej - teeb meem thiab kev daws teeb meem 2

Qhov siab (h) = 1.5 m – 0.25 m = 1.25 meters

Kev nrawm vim lub ntiajteb txawj nqus (g) = 10 m/s ²

Xav tau: Qhov ceev ntawm dej (v)

Tshuaj:

v _t² = 2 gh = 2(10)(1.25) = 25

v _t = √25 = 5 m/s

3. Ib lub thawv puv dej thiab muaj ib lub qhov, raws li pom hauv daim duab hauv qab no. Yog tias qhov kev nrawm vim lub ntiajteb txawj nqus yog 10 ms ^-2 , qhov ceev ntawm dej hla lub qhov ntawd yog dab tsi.

Paub:

Qhov siab (h) = 1 m – 0.20 m = 0.8 meters Kev ua haujlwm ntawm cov kua dej - teeb meem thiab kev daws teeb meem 3

Kev nrawm vim lub ntiajteb txawj nqus (g) = 10 m/s ²

Xav tau: Qhov ceev ntawm dej (v)

Tshuaj:

v _t² = 2 gh = 2(10)(0.8) = 16

v _t = √16 = 4 m/s

4. Ib lub thawv puv dej thiab muaj ib lub qhov, raws li pom hauv daim duab hauv qab no. Yog tias qhov kev nrawm vim lub ntiajteb txawj nqus yog 10 ms ^-2 , qhov ceev ntawm dej hla lub qhov ntawd yog dab tsi.

Paub:

Qhov siab (h) = 20 cm = 0.2 meters Kev ua haujlwm ntawm cov kua dej - teeb meem thiab kev daws teeb meem 4

Kev nrawm vim lub ntiajteb txawj nqus (g) = 10 m/s ²

Xav tau: Qhov ceev ntawm dej (v)

Tshuaj:

5. Ib lub thawv puv dej thiab muaj ob lub qhov , raws li pom hauv daim duab hauv qab no. Qhov piv ntawm x ₁ rau x ₂ yog dab tsi?

Kev daws teeb meem

Kev ua haujlwm ntawm cov kua dej - teeb meem thiab kev daws teeb meem 6

Lub sijhawm ntawm kev poob dej dawb los ntawm qhov 1: Kev ua haujlwm ntawm cov kua dej - teeb meem thiab kev daws teeb meem 7

h = 1/2 ntawm ²

0.8 = 1/2 (10) t ²

0.8 = 5 t ²

t2 = 0.8 / 5 = ^0.16

t = 0.4 vib nas this

Lub sijhawm ntawm kev poob dej dawb los ntawm qhov 2:

h = 1/2 ntawm ²

0.5 = 1/2 (10) t ²

0.5 = 5 t ²

t2 = 0.5 / 5 = ^0.1

t = √0.1 vib nas this

Qhov nrug kab rov tav (x):

x ₁ = v ₁ t ₁ = (2)(0.4) = 0.8 meters

x ₂ = v ₂ t ₂ = (√10)(√0.1) = (10)(0.1) = 1 'meter'

Qhov piv ntawm x ₁ rau x ₂ :

x1 _: x2 = _0.8 : 1 = 8: 10 = 4: ₅

Qhov sib npaug ntawm kev sib txuas ntxiv mus

6. Dej ntws los ntawm ib lub yeeb nkab uas muaj ntau txoj kab uas hla, A mus rau B thiab tom qab ntawd mus rau C. Qhov piv ntawm A mus rau C yog 8: 3. Yog tias qhov ceev ntawm dej hauv yeeb nkab A yog v, qhov ceev ntawm dej hauv yeeb nkab C yog dab tsi.

Paub:

Thaj Chaw ntawm A (A_A= 8 TZS Kev ua haujlwm ntawm cov kua dej - teeb meem thiab kev daws teeb meem 8

Thaj chaw ntawm C (A _C ) = 3

Qhov ceev ntawm dej hauv yeeb nkab A (v _A ) = v

Xav tau: Qhov ceev ntawm dej hauv yeeb nkab C (v _C )

Tshuaj:

Tus qauv ntawm kev sib txuas:

A _A v _A = A _C v _C

8v = _3vC

vC = _8/3 v

7. Yog tias qhov ceev ntawm dej hauv cov kav dej uas muaj txoj kab uas hla 12 cm yog 10 cm/s, qhov ceev ntawm dej hauv cov kav dej uas muaj txoj kab uas hla 8 cm yog dab tsi?

Paub:

Txoj kab uas hla 1 (d ₁ ) = 12 cm, lub vojvoog 1 (r ₁ ) = 6 cm

Txoj kab uas hla 2 (d ₂ ) = 8 cm, lub vojvoog 2 (r ₂ ) = 4 cm

Qhov ceev ntawm dej 1 (v ₁ ) = 10 cm/s

Xav tau: Qhov ceev ntawm dej 2 (v ₂ )

Tshuaj:

luas 1 (A ₁ ) = π r ² = π 6 ² = 36π cm ²

luas 2 (A ₂ ) = π r ² = π 4 ² = 16π cm ²

Tus qauv ntawm kev sib txuas:

A ₁ vs ₁ = A ₂ vs ₂

(36π)(10) = (16π) _v2

(36)(10) = (16) v ₂

360 = (16) v ₂

v2 = _360/16

v2 = _22.5 cm/s

8. Dej ntws los ntawm ib lub yeeb nkab uas muaj ntau txoj kab uas hla, raws li pom hauv daim duab hauv qab no. Yog tias thaj tsam 1 (A ₁ ) = 8 cm ² , A ₂ = 2 cm ² thiab qhov ceev ntawm dej hauv yeeb nkab 2 = v _{2 = 2 m/s ces qhov ceev ntawm dej hauv yeeb nkab 1 = v}₁ yog dab tsi.

Paub:

Cheeb Tsam 1 (A₁) = 8 cm²

Cheeb Tsam 2 (A ₂ ) = 2 cm ²

Qhov ceev ntawm dej hauv yeeb nkab 2 (v ₂ ) = 2 m/s

Xav tau: qhov ceev ntawm dej hauv yeeb nkab 1 (v ₁ )

Tshuaj:

Tus qauv ntawm kev sib txuas:

A ₁ vs ₁ = A ₂ vs ₂

8 rau ₁ = (2)(2)

8 vs ₁ = 4

v ₁ = 4 / 8 = 0.5 m/s

9. Yog tias txoj kab uas hla ntawm cov yeeb nkab loj dua yog 2 npaug ntawm txoj kab uas hla ntawm cov yeeb nkab me dua, qhov ceev ntawm cov kua dej ntawm cov yeeb nkab me dua yog dab tsi.

Paub:

Txoj kab uas hla ntawm cov yeeb nkab loj dua (d₁= 2 TZS Kev ua haujlwm ntawm cov kua dej - teeb meem thiab kev daws teeb meem 10

Lub vojvoog ntawm cov yeeb nkab loj dua (r ₁ ) = ½ d ₁ = ½ (2) = 1

luas cov yeeb nkab loj ( A ₁ ) = π r ₁² = π (1) ² = π (1) = π

Txoj kab uas hla ntawm cov yeeb nkab me dua (d ₂ ) = 1

Lub vojvoog ntawm cov yeeb nkab me dua (r ₂ ) = ½ d ₂ = ½ (1) = ½

luas alas ( A ₂ ) = π r ₂² = π (1/2) ² = π (1/4) = ¼ π

Qhov ceev ntawm cov kua dej ntawm cov yeeb nkab loj dua ( v ₁ ) = 4 m/s

Xav tau: Qhov ceev ntawm cov kua dej ntawm cov yeeb nkab me dua ( v ₂ )

Tshuaj:

Tus qauv ntawm kev sib txuas:

A ₁ vs ₁ = A ₂ vs ₂

π 4 = ¼ π (v ₂ )

4 = ¼ ( _v2 )

v2 = 8 m/ _s

Bernoulli txoj cai thiab cov qauv sib npaug

10. Dej raug pumped nrog lub compressor 120 kP nkag mus rau hauv cov yeeb nkab qis (1) thiab ntws mus rau saum toj ntawm qhov ceev ntawm 1 m / s. Kev nrawm vim lub ntiajteb txawj nqus yog 10 m / s thiab dej ceev yog 1000 kg / m ^-3 . Lub zog dej ntawm cov yeeb nkab sab saud yog dab tsi (II ).

Paub:

Lub vojvoog ntawm cov yeeb nkab qis dua (r)₁) = 12 cm Kev ua haujlwm ntawm cov kua dej - teeb meem thiab kev daws teeb meem 11

Lub vojvoog ntawm cov yeeb nkab qis dua (r ₂ ) = 6 cm

Lub zog dej hauv cov kav dej qis (p ₁ ) = 120 kPa = 120,000 Pascal

Qhov ceev ntawm dej hauv cov yeeb nkab qis (v ₁ ) = 1 ms ^-1

Qhov siab ntawm cov yeeb nkab qis dua (h ₁ ) = 0 m

Qhov siab ntawm cov yeeb nkab sab saud (h ₂ ) = 2 m

Kev nrawm vim yog lub ntiajteb txawj nqus (g) = 10 ms ^-2

Qhov ceev ntawm dej = 1000 kg.m ^-3

Xav tau: Lub zog dej hauv cov yeeb nkab 2 (p ₂ )

Tshuaj:

Qhov ceev ntawm dej hauv yeeb nkab 2 yog xam nrog cov qauv ntawm kev sib txuas:

Kev ua haujlwm ntawm cov kua dej - teeb meem thiab kev daws teeb meem 12

Lub zog dej hauv cov yeeb nkab 2 yog xam los ntawm kev siv Bernoulli equation:

Kev ua haujlwm ntawm cov kua dej - teeb meem thiab kev daws teeb meem 13

11. Ib lub yeeb nkab loj 5 meters saum av thiab ib lub yeeb nkab me 1 meters saum av. Qhov ceev ntawm cov dej hauv ib lub yeeb nkab loj yog 36 km/h nrog lub siab ntawm 9.1 x 10 ⁵ Pa, thaum lub siab ntawm lub yeeb nkab me yog 2.10 ⁵ Pa. Qhov ceev ntawm cov dej hauv lub yeeb nkab me yog dab tsi ? Qhov ceev ntawm cov dej = 10 ³ kg/ ^m3

Paub:

Lub zog dej hauv cov yeeb nkab loj (p₁) = 9.1 x 10⁵Pascal = 910,000 Pascal Kev ua haujlwm ntawm cov kua dej - teeb meem thiab kev daws teeb meem 14

Lub zog dej hauv cov yeeb nkab me me (p ₂ ) = 2 x 10 ⁵ Pascals = 200,000 Pascals

Qhov ceev ntawm dej hauv cov yeeb nkab loj (v ₁ ) = 36 km/h = 36(1000)/(3600) = 36000/3600 =10 m/s

Qhov siab ntawm cov yeeb nkab loj (h ₁ ) = -4 meters

Qhov siab ntawm cov yeeb nkab me me (h ₂ ) = 0 meters

Kev nrawm vim yog lub ntiajteb txawj nqus (g) = 10 ms ^-2

Qhov Ceev ntawm dej = 1000 kg/ ^m3

Xav tau: Qhov ceev ntawm dej hauv cov yeeb nkab me me (v ₂ )

Tshuaj:

Qhov ceev ntawm dej hauv cov yeeb nkab me me (v ₂ ) yog xam los ntawm kev siv cov qauv ntawm Bernoulli:

Kev ua haujlwm ntawm cov kua dej - teeb meem thiab kev daws teeb meem 15

12. Cov yeeb nkab uas muaj lub vojvoog ntawm 15 cm txuas nrog lwm cov yeeb nkab uas muaj lub vojvoog ntawm 5 cm. Ob leeg nyob rau hauv txoj haujlwm kab rov tav. Lub zog ntawm cov dej ntws hauv cov yeeb nkab loj yog 1 m/s ntawm lub zog siab ntawm 10 5 N/m2. Lub zog ^dej ntawm cov ^yeeb nkab me yog dab tsi (1 g cm ^-3 )

Paub:

Lub vojvoog ntawm cov yeeb nkab loj (r ₁ ) = 15 cm = 0.15 m

Lub vojvoog ntawm cov yeeb nkab me me (r2 ₎ = 5 cm = 0.05 m

Lub zog dej hauv cov yeeb nkab loj (p ₁ ) = 10 ⁵ N m ^-2 = 100.000 N m ^-2

Qhov ceev ntawm dej hauv cov yeeb nkab loj (v ₁ ) = 1 ms ^-1

Kev nrawm vim yog lub ntiajteb txawj nqus (g) = 10 ms ^-2

Qhov ceev ntawm dej = 1 gr cm ^-3 = 1000 kg m ^-3

Qhov siab sib txawv (Δh) = 0.

Xav tau: Siab nyob rau hauv lub yeeb nkab me me (p ₂ )

Tshuaj:

Qhov ceev ntawm dej hauv yeeb nkab 2 yog xam los ntawm kev siv cov qauv sib txuas:

Kev ua haujlwm ntawm cov kua dej - teeb meem thiab kev daws teeb meem 16

Lub siab ntawm dej hauv cov yeeb nkab me me (p ₂ ) yog xam los ntawm kev siv tus qauv ntawm Bernoulli:

Kev ua haujlwm ntawm cov kua dej - teeb meem thiab kev daws teeb meem 17

Cov kua dej dynamics yog dab tsi?
- teb: Kev kawm txog cov kua dej (fluid dynamics) yog ib ceg ntawm kev kawm txog physics uas kawm txog kev txav ntawm cov kua dej (kua thiab cov pa) thiab cov zog uas ua rau lawv. Nws suav nrog cov ntsiab cai thiab cov qauv uas piav qhia txog kev ntws ntawm cov kua dej, cuam tshuam nrog cov ciam teb khov kho, thiab cuam tshuam rau ib leeg li cas.
Qhov txawv ntawm laminar thiab turbulent flow yog dab tsi?
- teb: Cov dej ntws laminar yog tus cwj pwm los ntawm cov txheej dej du thiab sib luag uas txav mus rau hauv txoj kev zoo. Cov dej ntws turbulent, ntawm qhov tod tes, yog chaotic, nrog eddies, swirls, thiab fluctuations sai. Turbulence feem ntau tshwm sim ntawm qhov ceev ceev lossis hauv cov channel tsis sib xws.
Lub tswv yim ntawm viscosity tseem ceeb npaum li cas hauv cov kua dej dynamics?
- teb: Qhov viscosity ntsuas qhov tsis kam ntawm cov kua dej rau kev txiav lossis ntws. Cov kua dej uas muaj viscosity siab (xws li zib ntab) tiv taus kev ntws ntau dua li cov kua dej uas muaj viscosity qis (xws li dej). Hauv cov kua dej dynamics, viscosity ua lub luag haujlwm tseem ceeb hauv kev txiav txim siab qhov xwm txheej ntawm cov kua dej ntws, kev faib tawm lub zog, thiab lub zog rub.
Txoj cai Bernoulli yog dab tsi?
- teb: Bernoulli txoj cai hais tias nyob rau hauv ib qho kev ntws tas mus li, qhov sib sau ua ke ntawm lub zog siab, lub zog kinetic, thiab lub zog muaj peev xwm ib chav tsev ntim tseem ruaj khov. tshwj xeeb, qhov twg qhov ceev ntawm cov kua dej siab, qhov siab qis, thiab rov ua dua.
Lub hauv paus ntsiab lus ntawm kev nqa hauv aerodynamics cuam tshuam li cas rau cov kua dej dynamics?
- teb: Qhov kev nqa ntawm lub tis dav hlau tuaj yeem piav qhia siv Bernoulli txoj cai thiab Newton txoj cai thib peb. Thaum cua ntws hla lub tis, nws txav mus sai dua hla qhov nkhaus saum npoo dua li hauv qab, tsim kom muaj qhov sib txawv ntawm lub siab. Qhov sib txawv ntawm lub siab no, ua ke nrog qhov kev hloov pauv ntawm huab cua los ntawm lub tis, ua rau muaj lub zog lossis kev nqa mus rau saum.
Qhov sib npaug ntawm kev sib txuas lus hauv cov kua dej yog dab tsi?
- teb: Tus qauv ntawm kev sib txuas lus hais tias qhov khoom ntawm thaj tsam hla (A) ntawm cov dej ntws thiab nws qhov ceev (v) tseem ruaj khov raws li cov dej ntws hauv cov dej ntws ruaj khov. Hauv lej, $A_{1} v_{1} = A_{2} v_{2}$ , qhov twg $A_{1}$ thiab $A_{2}$ yog cov cheeb tsam hla thiab $v_{1}$ thiab $v_{2}$ yog cov velocity ntawm ob lub ntsiab lus raws txoj kab streamline.
Tus lej Reynolds ua lub luag haujlwm dab tsi hauv kev ua haujlwm ntawm cov kua dej?
- teb: Tus lej Reynolds yog ib qho ntau uas tsis muaj qhov ntev uas pab kwv yees qhov kev ntws (laminar, transitional, lossis turbulent) hauv cov kua dej dynamics. Nws yog txhais tias yog qhov sib piv ntawm cov zog inertial rau cov zog viscous thiab nyob ntawm cov yam xws li qhov ceev ntawm cov kua, qhov ntev ntawm cov yam ntxwv, thiab cov yam ntxwv ntawm cov kua.
Lub zog rub ua li cas rau cov khoom txav mus los hauv cov kua dej?
- teb: Lub zog rub tawm tsam qhov kev txav ntawm ib yam khoom hla cov kua dej. Nws tshwm sim vim yog qhov tsis kam ntawm cov kua dej thiab qhov sib txawv ntawm lub siab nyob ib puag ncig yam khoom. Qhov loj thiab qhov xwm txheej ntawm kev rub nyob ntawm cov yam xws li cov duab ntawm yam khoom, qhov ntxhib, qhov ceev, thiab cov yam ntxwv ntawm cov kua dej.
Cov nyhuv Venturi yog dab tsi?
- teb: Qhov Venturi effect yog hais txog qhov txo qis ntawm cov kua dej siab uas tshwm sim thaum cov kua dej ntws los ntawm ib feem ntawm cov yeeb nkab. Thaum cov kua dej qhov ceev nce ntxiv hauv seem (vim yog kev txuag ntawm qhov hnyav), nws qhov siab txo qis raws li Bernoulli txoj cai.
Vim li cas cov kua dej thiaj li nrawm dua thaum ntws los ntawm ib ntu nqaim ntawm cov yeeb nkab lossis cov channel?

teb: Tus cwj pwm no piav qhia tau los ntawm lub hauv paus ntsiab lus ntawm kev txuag qhov hnyav. Hauv kev ntws tas li, qhov ntim ntawm cov kua dej nkag mus rau hauv ib ntu ntawm cov yeeb nkab yuav tsum sib npaug rau qhov ntim tawm mus. Yog tias cov yeeb nkab nqaim, cov kua dej yuav tsum nrawm dua kom tib lub ntim dhau mus rau hauv ib lub sijhawm.