Piv txwv ntawm lub sijhawm ntawm inertia

25 Piv txwv ntawm Cov Lus Nug Txog Lub Sijhawm Inertia

Lub sijhawm ntawm Inertia ntawm ib qho khoom me me

1. Ib lub pob uas hnyav li 100 grams raug txuas rau ib txoj hlua uas ntev 30 cm raws li pom hauv daim duab. Lub sijhawm ntawm inertia lub pob nyob ib ncig ntawm lub axis AB yog ...
Kev Sib Tham
Nws paub tias:
Lub axis ntawm kev sib hloov yog AB
Qhov hnyav ntawm lub pob (m) = 100 grams = 100/1000 = 0,1 kilograms
Qhov deb ntawm lub pob ntawm lub axis ntawm kev tig (r) = 30 cm = 0,3 meters
Nug: Lub sijhawm ntawm inertia ntawm lub pob (I)
Lus teb:
Kuv = Mr.² = (0,1 kg)(0,3 m)²
Kuv = (0,1 kg)(0,09 m²)
Kuv = 0,009 kg/m²²

2. Qhov hnyav ntawm lub pob m₁ yog 100 grams thiab qhov hnyav ntawm lub pob yog m₂ yog 200 grams. Ob lub pob txuas nrog los ntawm ib txoj hlua ntev 60 cm nrog qhov hnyav tsis tseem ceeb. Lub AB axis nyob hauv nruab nrab ntawm txoj hlua. Lub sijhawm inertia ntawm ob lub pob ncig lub AB axis yog…
Kev Sib Tham
Nws paub tias:
Qhov hnyav ntawm lub pob 1 (m₁) = 100 grams = 100/1000 = 0,1 kilograms
Qhov deb ntawm lub pob 1 ntawm lub axis ntawm kev sib hloov (r₁) = 30 cm = 30/100 = 0,3 meters
Qhov hnyav ntawm lub pob 2 (m₂) = 200 grams = 200/1000 = 0,2 kilograms
Qhov deb ntawm lub pob 2 ntawm lub axis ntawm kev sib hloov (r₂) = 30 cm = 30/100 = 0,3 meters
Nug: Lub sijhawm ntawm inertia ntawm lub kaw lus ntawm ob lub pob
Lus teb:
Kuv = m₁ r₁² +m₂ r₂²
Kuv = (0,1 kg)(0,3 m)² + (0,2 kg)(0,3 m)²
Kuv = (0,1 kg)(0,09 m²) + (0,2 kg)(0,09 m²)
Kuv = 0,009 kg/m²² + 0,018 kg m²
Kuv = 0,027 kg/m²²

3. Qhov hnyav ntawm lub pob m₁ yog 200 grams thiab qhov hnyav ntawm lub pob yog m₂ yog 100 grams. Ob lub pob txuas nrog ib txoj hlua uas ntev 60 cm thiab nws qhov hnyav tsis raug saib xyuas. Lub AB axis nyob ntawm lub pob m₂Lub sijhawm ntawm inertia ntawm lub kaw lus ntawm ob lub pob ncig lub AB axis yog ...
Kev Sib Tham
Nws paub tias:
Qhov hnyav ntawm lub pob 1 (m₁) = 200 grams = 200/1000 = 0,2 kilograms
Qhov deb ntawm lub pob 1 ntawm lub axis ntawm kev sib hloov (r₁) = 60 cm = 60/100 = 0,6 meters
Qhov hnyav ntawm lub pob 2 (m₂) = 100 grams = 100/1000 = 0,1 kilograms
Qhov deb ntawm lub pob 2 ntawm lub axis ntawm kev sib hloov (r₂) = 0 'meter'
Nug: Lub sijhawm ntawm inertia ntawm lub kaw lus ntawm ob lub pob
Lus teb:
Kuv = m₁ r₁² +m₂ r₂²
Kuv = (0,2 kg)(0,6 m)² + (0,2 kg)(0)²
Kuv = (0,2 kg)(0,36 m²) + 0
Kuv = 0,072 kg/m²²

4. Txhua lub pob muaj qhov hnyav li 100 grams thiab txuas nrog ib txoj hlua uas tsis hnyav heev. Qhov ntev ntawm txoj hlua yog 60 cm thiab qhov dav yog 30 cm. Txheeb xyuas lub sijhawm ntawm inertia ntawm lub pob system ncig lub AB axis…
Kev Sib Tham
Nws paub tias:
Qhov hnyav ntawm lub pob 1 (m₁) = m₂ = kuv₃ = kuv₄ = 100 grams = 100/1000 = 0,1 kilograms
Qhov deb ntawm lub pob 1 ntawm lub axis ntawm kev sib hloov (r₁) = 30 cm = 30/100 = 0,3 meters
Qhov deb ntawm lub pob 2 ntawm lub axis ntawm kev sib hloov (r₂) = 30 cm = 30/100 = 0,3 meters
Qhov deb ntawm lub pob 3 ntawm lub axis ntawm kev sib hloov (r₃) = 30 cm = 30/100 = 0,3 meters
Qhov deb ntawm lub pob 4 ntawm lub axis ntawm kev sib hloov (r₄) = 30 cm = 30/100 = 0,3 meters
Nug: Lub sijhawm ntawm inertia ntawm lub pob system
Lus teb:
Kuv = m₁ r₁² +m₂ r₂² +m₃ r₃² +m₄ r₄²
Kuv = (0,1 kg)(0,3 m)² + (0,1 kg)(0,3 m)² + (0,1 kg)(0,3 m)² + (0,1 kg)(0,3 m)²
Kuv = (0,1 kg)(0,09 m²) + (0,1 kg)(0,09 m²) + (0,1 kg)(0,09 m²) + (0,1 kg)(0,09 m²)
Kuv = 0,036 kg/m²²

5. Saib daim duab hauv qab no. Plaub lub khoom me me, txhua lub muaj qhov hnyav 4m (ntawm qhov deb r ntawm qhov chaw nruab nrab), 3m (ntawm qhov deb r ntawm qhov chaw nruab nrab), 2m (ntawm qhov deb 2r ntawm qhov chaw nruab nrab), 2m (ntawm qhov deb r ntawm qhov chaw nruab nrab). Lub kaw lus nyob hauv lub dav hlau xy. Yog tias lub kaw lus tig ib ncig ntawm x-axis, ces lub sijhawm inertia ntawm lub kaw lus yog ...
A. 5 m r
B. 7 m r     
C. 5 m r²
D. 6 m r²
E. 7 m r²

Kev Sib Tham:
Nws yog paub :
Nws paub tias:
m₁ = 4m (qhov deb r ntawm qhov chaw nruab nrab), m₂ = 3m (qhov deb r ntawm qhov chaw nruab nrab), m₃ = 2m (qhov deb 2r ntawm qhov chaw nruab nrab), m₄ = 2m (qhov deb r ntawm qhov chaw nruab nrab)
Nug :
Lub sijhawm ntawm inertia (Kuv)?
Jawb :
Cov mis rau lub sijhawm ntawm inertia ntawm ib qho khoom me me :
Kuv = Mr.²
Lub system tig ib ncig ntawm x-axis kom m₂ thiab m₄ nyob rau ntawm txoj kab sib hloov. Vim tias nws nyob rau ntawm txoj kab sib hloov, r₂ thiab r₄ muaj nqis xoom.
I₁ = kuv₁ r₁² = 4mr²
I₂ = kuv₂ r₂² = 3m (0)² = 0
I₃ = kuv₃ r₃² = 2m (2r)² = 2m (4r)²) = 8mr²
I₄ = kuv₄ r₄² = 2m (0)² = 0
Lub sijhawm ntawm inertia ntawm lub system :
I = kuv₁ + Kuv₂ + Kuv₃ + Kuv₄
Kuv = 4m² + 8m²
Kuv = 12m²

6. Qws AB muaj qhov hnyav ntawm 3 kg thaum tig los ntawm B, nws lub zog ntawm inertia yog 27 kg m²Yog tias tig los ntawm C, lub sijhawm ntawm inertia dhau los ua ...
A. 70 kg m²
B. 76 kg m²
C. 92 kg m²
D. 98 kg m²
E. 108 kg m²
Kev Sib Tham:

Nws yog paub :
m = 3 kg
I_B = 27 kg/m²²
Nug :
I_C ?
Jawb :
I_B = Yawg.²
27 kg m² = (3 kg)(r²)
27 kg m² / 3 kg = r²
9 m² =r²
r = 3 m
Length AB = Length AC = 3 meters

Lub sijhawm ntawm Inertia lub pas nrig thaum tig los ntawm C:
I_C = Yawg.²
I_C = (3 kg)(6 m)²
I_C = (3 kg)(36 m²) = 108 kg/m²²

7.

Ob lub pob, suav tias yog cov khoom me me, raug txuas los ntawm txoj hlua hlau raws li pom hauv daim duab. Yog tias qhov hnyav ntawm cov pob P thiab Q yog 600 grams thiab 400 grams feem, ces lub sijhawm ntawm inertia ntawm lub kaw lus ntawm ob lub pob ncig lub axis AB yog…

A. 0,008 kg.m²
B. 0,076 kg.m²
C. 0,124 kg.m²
D. 0,170 kg.m²
E. 0,760 kg.m²

Kev Sib Tham
Nws yog paub :
Qhov hnyav ntawm lub pob P (m_P) = 600 grams = 0,6 kg
Qhov hnyav ntawm lub pob Q (m_Q) = 400 grams = 0,4 kg
Qhov deb ntawm lub pob P ntawm lub axis ntawm kev sib hloov (r)_P) = 20 cm = 0,2 meters
Qhov deb ntawm lub pob Q ntawm lub axis ntawm kev sib hloov (r)_Q) = 50 cm = 0,5 meters
Nug : Lub sijhawm ntawm inertia (I) lub kaw lus nrog rau lub axis lossis axis ntawm kev sib hloov AB
Jawb :

Cov mis rau lub sijhawm ntawm inertia ntawm ib qho khoom me me :
Kuv = Mr.²
Kev piav qhia: Kuv = lub sijhawm ntawm inertia, m = qhov hnyav ntawm cov khoom me me, r = qhov deb ntawm cov khoom me me ntawm lub axis ntawm kev tig
Lub sijhawm ntawm inertia ntawm lub pob P
I_P = (m_P)(r_P²) = (0,6)(0,2)² = (0,6)(0,04) = 0,024 kg m²²
Lub sijhawm ntawm inertia ntawm lub pob Q
I_Q = (m_Q)(r_Q²) = (0,4)(0,5)² = (0,4)(0,25) = 0,1 kg m²²
Lub sijhawm ntawm inertia ntawm lub kaw lus particle :
I = kuv_P + Kuv_Q = 0,024 + 0,1 = 0,124 kg m²²
Cov lus teb yog C.

8.

Ob lub pob txuas nrog ib txoj hlua (qhov hnyav ntawm txoj hlua tsis raug tsis quav ntsej) raug teeb tsa raws li pom hauv daim duab. Qhov loj ntawm lawv lub zog inertia yog…

A. 20 x 10^-3 kg.m²
B. 25 x 10^-3 kg.m²
C. 11 x 10^-2 kg.m²
D. 55 x 10^-2 kg.m²
E. 80 x 10^-2 kg.m²

Kev Sib Tham
Nws yog paub :
Qhov hnyav ntawm lub pob A (m_A) = 200 grams = 0,2 kg
Qhov hnyav ntawm lub pob B (m_B) = 400 grams = 0,4 kg
Qhov kev ncua deb ntawm lub pob A thiab lub axis ntawm kev sib hloov (r_A= 0 TZS
Qhov kev ncua deb ntawm pob B thiab lub axis ntawm kev sib hloov (r_B) = 25 cm = 0,25 meters
Nug Lub sijhawm ntawm inertia (I) ntawm lub kaw lus
Jawb :
Lub sijhawm ntawm inertia ntawm pob A
I_A = (m_A)(r_A²) = (0,2)(0)² = 0
Lub sijhawm ntawm inertia ntawm pob B
I_B = (m_B)(r_B²) = (0,4)(0,25)² = (0,4)(0,0625) = 0,025 kg m²²
Lub sijhawm ntawm inertia ntawm lub kaw lus particle :
I = kuv_A + Kuv_B = 0 + 0,025 = 0,025 kg m²² Luas = 25 x 10^-3 kg/m²
Cov lus teb yog B.

9.
Saib daim duab ntawm ob lub pob txuas nrog ib txoj hlua. Qhov ntev ntawm txoj hlua = 12 m, l₁ = 4 m thiab qhov hnyav ntawm cov hlau tsis quav ntsej, ces qhov loj ntawm lub sijhawm ntawm inertia ntawm lub kaw lus yog ...
A. 52,6 kg m²
B. 41,6 kg m²
C. 34,6 kg m²
D. 22,4 kg m²
E. 20,4 kg m²
Kev Sib Tham
Nws yog paub :
Qhov hnyav ntawm lub pob A (m_A) = 0,2 kg
Qhov hnyav ntawm lub pob B (m_B) = 0,6 kg
Qhov kev ncua deb ntawm lub pob A thiab lub axis ntawm kev sib hloov (r_A) = 4 'meter'
Qhov kev ncua deb ntawm pob B thiab lub axis ntawm kev sib hloov (r_B) = 12 – 4 = 8 meters
Nug Lub sijhawm ntawm inertia (I) ntawm lub kaw lus
Jawb :
Lub sijhawm ntawm inertia ntawm pob A
I_A = (m_A)(r_A²) = (0,2)(4)² = (0,2)(16) = 3,2 kg m²²
Lub sijhawm ntawm inertia ntawm pob B
I_B = (m_B)(r_B²) = (0,6)(8)² = (0,6)(64) = 38,4 kg m²²
Lub sijhawm ntawm inertia ntawm lub kaw lus particle :
I = kuv_A + Kuv_B = 3,2 + 38,4 = 41,6 kg m²²
Cov lus teb yog B.

Lub Sijhawm ntawm Inertia ntawm Lub Cev Rigid

10. Ib tug pas nrig khov kho muaj qhov hnyav ntawm 2 kg thiab ntev ntawm 2 meters. Txheeb xyuas lub sijhawm ntawm inertia ntawm tus pas nrig yog tias lub axis ntawm kev tig nyob hauv nruab nrab ntawm tus pas nrig!
Kev Sib Tham
Nws paub tias:
Qhov hnyav ntawm cov pas nrig khov kho (M) = 2 kg
Qhov ntev ntawm cov kav khov kho (L) = 2 meters
Nug: Lub sijhawm ntawm inertia
Lus teb:
Cov mis rau lub sijhawm ntawm inertia ntawm ib tug pas nrig yog tias lub axis ntawm kev sib hloov nyob hauv nruab nrab ntawm tus pas nrig:
Kuv = (1/12) ML²
Kuv = (1/12) (2 kg)(2 m)²
Kuv = (1/12) (2 kg)(4 m²)
Kuv = (1/12)(8 kg m2)²)
Kuv = 8/12 kg/m²²
Kuv = 2/3 kg/m²²

11. Ib tug pas nrig khov kho muaj qhov hnyav ntawm 2 kg thiab ntev ntawm 2 meters. Txheeb xyuas lub sijhawm ntawm inertia ntawm tus pas nrig yog tias lub axis ntawm kev tig nyob ntawm ib kawg ntawm tus pas nrig!
Kev Sib Tham
Nws paub tias:
Qhov hnyav ntawm cov pas nrig khov kho (M) = 2 kg
Qhov ntev ntawm cov kav khov kho (L) = 2 meters
Nug: Lub sijhawm ntawm inertia
Lus teb:
Cov mis rau lub sijhawm ntawm inertia ntawm ib tug pas nrig yog tias lub axis ntawm kev sib hloov nyob rau ntawm ib kawg ntawm tus pas nrig:
Kuv = (1/3) ML²
Kuv = (1/3) (2 kg)(2 m)²
Kuv = (1/3) (2 kg)(4 m²)
Kuv = (1/3)(8 kg m2)²)
Kuv = 8/3 kg/m²²

12. Txheeb xyuas lub sijhawm ntawm inertia ntawm lub disc khov kho nrog qhov hnyav ntawm 10 kg thiab lub vojvoog ntawm 0,1 meters, yog tias lub axis ntawm kev tig yog nyob rau hauv nruab nrab ntawm lub disc, raws li qhia hauv daim duab!
Kev Sib Tham
Nws paub tias:
Qhov hnyav ntawm lub disc khov kho (M) = 10 kg
Lub vojvoog ntawm lub disc khov kho (L) = 0,1 meters
Nug: Lub sijhawm ntawm inertia ntawm lub disc khov kho
Lus teb:
Cov mis rau lub sijhawm ntawm inertia ntawm tus pas nrig yog tias lub axis ntawm kev sib hloov nyob rau hauv nruab nrab ntawm lub disc:
Kuv = (1/2) ML²
Kuv = (1/2) (10 kg)(0,1 m)²
Kuv = (1/2) (10 kg)(0,01 m²)
Kuv = (1/2)(0,1 kg m2)²)
Kuv = 0,05 kg/m²²

13. Txheeb xyuas lub sijhawm ntawm inertia ntawm lub pob khov kho uas muaj qhov hnyav ntawm 20 kg thiab lub vojvoog ntawm 0,1 meters, yog tias lub axis ntawm kev tig yog nyob rau hauv nruab nrab ntawm lub pob, raws li qhia hauv daim duab!
Kev Sib Tham
Nws paub tias:
Qhov hnyav ntawm lub pob khoom khov kho (M) = 20 kg
Lub vojvoog ntawm lub pob khov kho (L) = 0,1 meters
Nug: Lub sijhawm ntawm inertia
Lus teb:
Cov mis rau lub sijhawm ntawm inertia ntawm ib tug pas nrig yog tias lub axis ntawm kev sib hloov nyob rau hauv qhov chaw ntawm ib lub pob zeb khov kho:
Kuv = (2/5) ML²
Kuv = (2/5)(20 kg)(0,1 m)²
Kuv = (2/5)(20 kg)(0,01 m²)
Kuv = (2/5)(0,2 kg m2)²)
Kuv = 0,4/5 kg/m²²
Kuv = 0,08 kg/m²²

14. Txheeb xyuas lub sijhawm ntawm inertia ntawm lub pob nyias, khoob nrog qhov hnyav ntawm 0,5 kg thiab lub vojvoog ntawm 0,1 meters, yog tias lub axis ntawm kev tig yog nyob rau hauv nruab nrab ntawm lub pob, raws li qhia hauv daim duab!
Kev Sib Tham
Nws paub tias:
Qhov hnyav ntawm lub pob nyias (M) = 0,5 kg
Lub vojvoog ntawm lub pob nyias nyias (L) = 0,1 meters
Nug: Lub sijhawm ntawm inertia mis
Lus teb:
Cov mis rau lub sijhawm ntawm inertia ntawm ib tug pas nrig yog tias lub axis ntawm kev sib hloov nyob rau hauv qhov chaw ntawm ib lub pob nyias:
Kuv = (2/3) ML²
Kuv = (2/3) (0,5 kg)(0,1 m)²
Kuv = (2/3) (0,5 kg)(0,01 m²)
Kuv = (2/3)(0,005 kg m2)²)
Kuv = 0,01/3 kg/m²²

15. Ib lub phaj khov kho uas muaj plaub fab muaj qhov hnyav li 2 kg, ntev li 0,5 meters thiab dav li 0,2 meters. Txheeb xyuas lub sijhawm ntawm inertia ntawm lub phaj khov kho yog tias lub axis ntawm kev tig yog nyob rau hauv nruab nrab ntawm lub phaj, raws li qhia hauv daim duab!
Kev Sib Tham
Nws paub tias:
Qhov hnyav ntawm ib lub phaj khov kho plaub fab (M) = 2 kg
Phaj ntev (a) = 0,5 meters
Qhov dav ntawm phaj (b) = 0,2 meters
Nug: Lub sijhawm ntawm inertia mis
Lus teb:
Cov mis rau lub sijhawm ntawm inertia ntawm lub phaj khoom rectangular yog tias lub axis ntawm kev sib hloov nyob rau hauv nruab nrab ntawm lub phaj khoom:
Kuv = (1/12) M (a)² + b²)
Kuv = (1/12)(2)(0,52 + 0,22)
Kuv = (2/12)(0,25 + 0,04)
Kuv = (1/6)(0,29)
Kuv = 0,29/6 kg/m²²

16. Cov lus hauv qab no yog cov lus hais txog cov yam ntxwv ntawm kev txav mus los.

(1) Qhov ceev ntawm lub kaum sab xis

(2) Qhov chaw ntawm lub axis ntawm kev tig

(3) Cov duab ntawm yam khoom

(4) Qhov hnyav ntawm ib yam khoom

Cov yam tseem ceeb uas cuam tshuam rau qhov loj ntawm lub sijhawm inertia yog ...

A. (1), (2), (3) thiab (4)

B. (1), (2) thiab (3)

C. (1), (3) thiab (4)

D. (2), (3) thiab (4)

E. (2) thiab (4) xwb

Kev Sib Tham

Lub sijhawm ntawm inertia mis:

Kuv = Σm r ²

Kev piav qhia: m = qhov hnyav ntawm yam khoom, r = qhov deb ntawm lub axis ntawm kev tig.

Raws li cov qauv no, nws tau xaus lus tias lub sijhawm ntawm inertia yog cuam tshuam los ntawm qhov chaw ntawm lub axis ntawm kev sib hloov (2) thiab qhov hnyav ntawm cov khoom (4).

Cov lus teb yog yog E.

17. Ob lub pob uas suav tias yog cov khoom me me raug txuas nrog los ntawm txoj hlua hlau raws li pom hauv daim duab. Yog tias qhov hnyav ntawm cov pob P thiab Q yog 600 grams thiab 400 grams feem, ces lub sijhawm ntawm inertia ntawm lub kaw lus ntawm ob lub pob ncig lub axis AB yog…

A. 0,008 kg ^m2

B. 0,076 kg ^m2

C. 0,124 kg ^m2

D. 0,170 kg ^m2

E. 0,760 kg ^m2

Kev Sib Tham

Nws yog paub tias :

Lub axis ntawm kev sib hloov yog AB.

m _p = 600 grams = 0,6 kg, m _q = 400 grams = 0,4 kg

r _p = 20 cm = 0,2 m, r _q = 50 cm = 0,5 m

Lus Nug : Lub sijhawm ntawm inertia ntawm lub system yog dab tsi?

Lus teb :

_Kuv = _mprp2 + ^mqrq2​_​​_​^​

Kuv = (0,6 kg)(0,2 m) ² + (0,4 kg)(0,5 m) ²

Kuv = (0,6 kg)(0,04 m2 ⁾ + (0,4 kg)(0,25 ^m2 )

Kuv = 0,024 kg ^m2 + 0,1 kg ^m2

Kuv = 0,124 kg ^m2

Cov lus teb yog C.

18. Lub sijhawm ntawm inertia ntawm ib yam khoom tig ib ncig ntawm ib qho chaw ruaj khov yog cuam tshuam los ntawm ...

A. qhov hnyav ntawm yam khoom

B. qhov ntim ntawm yam khoom

C. qhov ceev ntawm cov khoom

D. kev nrawm ntawm lub kaum sab xis ntawm kev tig

E. qhov pib ntawm lub kaum sab xis

Kev Sib Tham

Lub sijhawm ntawm inertia mis:

Kuv = ∑mr ²

Kev piav qhia: Kuv = lub sijhawm ntawm inertia, m = pawg, r = qhov deb ntawm lub axis ntawm kev tig

Cov lus teb yog lawm yog A.

19. Ib tug pas nrig AB hnyav 2 kg raug tig hla lub ntsiab lus A thiab nws lub zog inertia yog 8 kg m2 ^. Yog tias nws raug tig hla lub ntsiab lus nruab nrab O (AO = OB), nws lub zog inertia dhau los ua...

A. 2 kg m²

B. 4 kg ^m2

C. 8 kg ^m2

D. 12 kg ^m2

E. 16 kg ^m2

Kev Sib Tham

Nws paub tias:

Qhov hnyav ntawm tus pas AB (m) = 2 kg

Yog tias nws tig los ntawm qhov chaw A kom lub vojvoog ntawm kev tig (r) = qhov deb AB = r ces lub sijhawm ntawm inertia (I) = 8 kg m ²

Lus Nug: Yog tias nws tig los ntawm qhov chaw O kom lub vojvoog ntawm kev tig (r) = qhov deb AO = qhov deb OB = 1/2 r ces lub sijhawm ntawm inertia dhau los ua (I) = ……

Lus teb:

Kuv = Mr. ²

8 kg ^m2 = (2 kg) ^r2

8 m2 ⁼ (2) ^r2

r2 = 8 ^m2 / ²

r2 = ^{4 m2}

r = 2 'meter'

Yog tias nws tig los ntawm qhov chaw O kom 1/2 r = 1 'meter', ces lub sijhawm ntawm inertia dhau los ua:

Kuv = mr ² = (2 kg)(1 m) ² = (2 kg)(1 m ² ) = 2 kg m ²

Cov lus teb yog lawm yog A.

20. Ob lub pob uas suav tias yog cov khoom me me raug txuas nrog los ntawm txoj hlua hlau raws li pom hauv daim duab. Yog tias qhov hnyav ntawm cov pob P thiab Q yog 600 grams thiab 400 grams feem, ces lub sijhawm ntawm inertia ntawm lub kaw lus ntawm ob lub pob ncig lub axis AB yog…

A. 0,008 kg.m²

B. 0,076 kg.m ²

C. 0,124 kg.m ²

D. 0,170 kg.m ²

E. 0,760 kg.m ²

Kev Sib Tham

Nws yog paub tias :

Qhov hnyav ntawm lub pob P (m _P ) = 600 grams = 0,6 kg

Qhov hnyav ntawm lub pob Q (m _Q ) = 400 grams = 0,4 kg

Qhov deb ntawm lub pob P ntawm lub axis ntawm kev tig (r _P ) = 20 cm = 0,2 meters

Qhov nrug ntawm lub pob Q ntawm lub axis ntawm kev tig (r _Q ) = 50 cm = 0,5 meters

Lo lus nug : Lub sijhawm ntawm inertia (I) ntawm lub kaw lus ncig lub axis lossis lub axis tig AB

Jawb :
Cov mis rau lub sijhawm ntawm inertia ntawm ib qho khoom me me :

Kuv = Mr. ²

Kev piav qhia: Kuv = lub sijhawm ntawm inertia, m = qhov hnyav ntawm cov khoom me me, r = qhov deb ntawm cov khoom me me ntawm lub axis ntawm kev tig

Lub sijhawm ntawm inertia ntawm lub pob P

IB ₌ (m _P )(r _P ² ) = (0,6)(0,2) ² = (0,6)(0,04) = 0,024 kg m ²

Lub sijhawm ntawm inertia ntawm lub pob Q

Kuv _Q = (m _Q )(r _Q ² ) = (0,4)(0,5) ² = (0,4)(0,25) = 0,1 kg m ²

Lub sijhawm ntawm inertia ntawm lub kaw lus particle :

Kuv = Kuv _P + Kuv _Q = 0,024 + 0,1 = 0,124 kg ^m2

Cov lus teb yog C.

21. Ob lub pob txuas nrog ib txoj hlua (qhov hnyav ntawm txoj hlua tsis raug tsis quav ntsej) raug teeb tsa raws li pom hauv daim duab. Qhov loj ntawm lawv lub zog inertia yog ...

A. 20 x 10^-3 kg.m²

B. 25 x 10 ^-3 kg.m ²

C. 11 x 10 ^-2 kg.m ²

D. 55 x 10 ^-2 kg.m ²

E. 80 x 10 ^-2 kg.m ²

Kev Sib Tham

Nws yog paub tias :

Qhov hnyav ntawm lub pob A (m _A ) = 200 grams = 0,2 kg

Qhov hnyav ntawm lub pob B (mB ₎ = 400 grams = 0,4 kg

Qhov kev ncua deb ntawm lub pob A thiab lub axis ntawm kev sib hloov (r _A ) = 0

Qhov kev ncua deb ntawm lub pob B thiab lub axis ntawm kev sib hloov (r _B ) = 25 cm = 0,25 meters

Lus Nug : Lub sijhawm ntawm inertia (I) ntawm lub kaw lus

Lus teb :

Lub sijhawm ntawm inertia ntawm pob A

Kuv _A = (m _A )(r ^A2 ₎ = (0,2)(0) ² = 0

Lub sijhawm ntawm inertia ntawm pob B

IB = (m _B )(rB2 _{) = (0,4)(} ^0,25 ) ² = (0,4)(0,0625) = 0,025 _kg ^m2

Lub sijhawm ntawm inertia ntawm lub kaw lus particle :

Kuv = Kuv _A + Kuv _B = 0 + 0,025 = 0,025 kg m2 ⁼ 25 x 10 ^-3 kg ^m2

Cov lus teb yog B.

22. Plaub lub khoom me me uas muaj qhov hnyav sib txawv nyob rau tib lub dav hlau nrog qhov chaw raws li pom hauv daim duab. Lub sijhawm ntawm inertia ntawm lub kaw lus nrog lub axis kab rov tav p yog…

A. 17 mb²

B. 22 mb ²

C. 27 mb ²

D. 31 mb ²

E. 33 mb ²

Kev Sib Tham

Axis ntawm kev tig = kab kab rov tav p

Nws paub tias:

Qhov hnyav ntawm cov khoom me me A (m _A ) = m

Qhov hnyav ntawm cov khoom me me B (mB ₎ = 2m

Qhov hnyav ntawm cov khoom me me C (mC ₎ = 3m

Qhov hnyav ntawm cov khoom me me D (m _D ) = 4m

Qhov deb ntawm cov khoom me me A ntawm lub axis ntawm kev tig (r _A ) = b

Qhov deb ntawm cov khoom me me B ntawm lub axis ntawm kev tig (r _B ) = b

Qhov deb ntawm cov khoom me me C ntawm lub axis ntawm kev tig (r _C ) = 2b

Qhov deb ntawm cov khoom me me D ntawm lub axis ntawm kev tig (r _D ) = 2b

Lo lus nug: Lub sijhawm ntawm inertia ntawm lub kaw lus nrog kab rov tav axis p

Lus teb:

Kuv = m_A r_A² +m_B r_B² +m_C r_C² +m_D r_D²

I = (m)(b) ² + (2m)(b) ² + (3m)(2b) ² + (4m)(2b) ²

I = mb ² + 2 mb ² + (3m)(4b ² ) + (4m)(4b ² )

I = mb ² + 2 mb ² + 12 mb ² + 16 mb ²

Kuv = 31 ^mb2

Cov lus teb yog D.

23. Saib daim duab hauv qab no!

Plaub lub khoom me me txuas nrog ib tug pas nrig uas tsis muaj qhov hnyav. Lub sijhawm ntawm inertia ntawm lub kaw lus ncig lub axis los ntawm m ₁ thiab m ₂ yog…

A. 1/200 kg.m²

B. 1/300 kg.m ²

C. 1/400 kg.m ²

D. 1/600 kg.m ²

E. 1/800 kg.m ²

Kev Sib Tham

Nws paub tias:

Qhov hnyav ntawm cov khoom me me 1 (m1 ₎ = 1/4 kg

Qhov hnyav ntawm cov khoom me me 2 (m2 ₎ = 1/2 kg

Qhov hnyav ntawm cov khoom me me 3 (m3 ₎ = 1/4 kg

Qhov hnyav ntawm cov khoom me me 4 (m4 ₎ = 1/4 kg

Qhov nrug ntawm cov khoom me me 1 ntawm lub axis ntawm kev tig (r ₁ ) = 0

Qhov nrug ntawm cov khoom me me 2 ntawm lub axis ntawm kev tig (r ₂ ) = 0

Qhov nrug ntawm cov khoom me me 3 ntawm txoj kab sib hloov (r ₃ ) = 10 cm = 10/100 meters = 1/10 meters

Qhov nrug ntawm cov khoom me me 4 ntawm txoj kab sib hloov (r ₄ ) = 10 cm = 10/100 meters = 1/10 meters

Lus Nug: Lub sijhawm ntawm inertia ntawm lub system

Lus teb:

Kuv = m₁ r₁² +m₂ r₂² +m₃ r₃² +m₄ r₄²

Kuv = (1/4)(0) ² + (1/2)(0) ² + (1/4)(1/10) ² + (1/4)(1/10) ²

Kuv = 0 + 0 + (1/4)(1/100) + (1/4)(1/100)

Kuv = 1/400 + 1/400

Kuv = 2/400

Kuv = 1/200 ^kg.m2

Cov lus teb yog lawm yog A.

24. Ob lub pob uas suav tias yog cov khoom me me raug txuas nrog los ntawm txoj hlua hlau raws li pom hauv daim duab. Yog tias qhov hnyav ntawm cov pob P thiab Q yog 600 grams thiab 400 grams feem, ces lub sijhawm ntawm inertia ntawm lub kaw lus ntawm ob lub pob ncig lub axis AB yog ...

A. 0,008 kg m²
B. 0,076 kg m²
C. 0,124 kg m²
D. 0,170 kg m²
E. 0,760 kg m²

Kev Sib Tham
Nws yog paub :
Lub axis ntawm kev sib hloov yog AB.
m_p = 600 grams = 0,6 kg, m_q = 400 grams = 0,4 kg
r_p = 20 cm = 0,2 m, r_q = 50 cm = 0,5 m
Nug : Lub sijhawm ntawm inertia ntawm lub system?
Jawb :
Kuv = m_p r_p² +m_q r_q²
Kuv = (0,6 kg)(0,2 m)² + (0,4 kg)(0,5 m)²
Kuv = (0,6 kg)(0,04 m²) + (0,4 kg)(0,25 m²)
Kuv = 0,024 kg/m²² + 0,1 kg m²
Kuv = 0,124 kg/m²²
Cov lus teb yog C.

25. Ob yam khoom khov kho, ib lub tog raj kheej thiab ib lub pob kheej kheej, nyob rau ntawm ib qho chaw tiaj tus. Ob yam khoom raug rub los ntawm tib lub zog, nrog rau qhov chaw sib cuag ntawm lawv qhov chaw, thiab muaj tib lub zog pib. Cov lus hauv qab no, cov lus twg yog qhov tseeb?

(1) Yog tias lub vojvoog ntawm ob yam khoom zoo ib yam thiab hauv pem teb du, ces qhov ceev ntawm ob yam khoom yeej ib txwm zoo ib yam.

(2) Yog tias lub vojvoog ntawm lub pob loj dua thiab hauv pem teb ntxhib ces qhov ceev ntawm ob yam khoom yuav ib txwm zoo ib yam.

(3) Yog tias cov radii tsis zoo ib yam thiab hauv pem teb nplua, ces qhov ceev kawg ntawm ob yam khoom yuav zoo ib yam tsuav yog qhov ceev pib sib txawv.

(4) Yog tias cov vojvoog tsis zoo ib yam thiab hauv pem teb nplua, qhov ceev ntawm ob yam khoom yuav ib txwm sib txawv.

Kev Sib Tham

Lub sijhawm ntawm inertia ntawm lub tog raj kheej khov kho = 1/2 mR ²

Lub sijhawm ntawm inertia ntawm lub pob khoom khov = 2/5 mR ²

Xav tias qhov hnyav ntawm ob yam khoom yog tib yam thiab lub radii ntawm ob yam khoom yog tib yam, ces lub sijhawm ntawm inertia ntawm lub tog raj kheej yog ntau dua (1/2) thaum lub sijhawm ntawm inertia ntawm lub pob khov kho yog me dua (2/5). Yog li, qhov ceev ntawm lub pob yog ntau dua vim nws lub sijhawm ntawm inertia yog me dua.

Yog tias lub vojvoog ntawm lub pob zeb loj dua, lub sijhawm inertia ntawm lub pob zeb nce ntxiv thiab tuaj yeem sib npaug rau lub sijhawm inertia ntawm lub tog raj kheej. Yog li ntawd, qhov ceev ntawm lub pob zeb thiab lub tog raj kheej tuaj yeem zoo ib yam.

Cov lus hais yog lawm (2)

 

Qhov chaw nug lus:

Cov Lus Nug Txog Kev Xeem Physics Hauv Tebchaws Rau Tsev Kawm Ntawv Theem Siab/Tsev Kawm Ntawv Theem Siab Ua Haujlwm