physics

1. Lub zog P raug siv rau ib kawg ntawm ib lub beam uas ntev li 2 m. Lub zog ntawm lub torque yog dab tsi ? Lub axis ntawm kev tig ntawm qhov chaw A.

Paub:

Lub zog (F) = 10 N

Qhov ntev ntawm AB (r _AB ) = 2 m

Lub zog F yog perpendicular rau lub beam.

Lub caj npab lever (l ) = r _AB sin 90 ^o = (2 m)(1) = 2 m

Xav tau: Lub zog torque nyob ib ncig ntawm lub axis ntawm kev sib hloov

Tshuaj:

Lub zog torque:

τ = Fl = (10 N)(2 m) = 20 N m

Lub cim ntxiv vim tias lub beam tig counterclockwise rotation.

[irp]

2. Qhov ntev ntawm ib lub beam AB yog 2 m thiab qhov loj ntawm lub zog F yog 10 N. Qhov loj ntawm lub torque yog dab tsi? Lub axis ntawm kev tig ntawm qhov chaw A.

Paub:

Lub zog (F) = 10 N

Qhov ntev ntawm AB (r _AB ) = 2 m

Lub caj npab ntawm lub lever (l ) = r _AB sin 60 ^o = (2 m)(0.5 √3 ) = √3 m

Xav tau: Lub zog torque nyob ib ncig ntawm lub axis ntawm kev sib hloov

Tshuaj:

Lub zog torque:

τ = Fl = (10 N)( √3 m) = 10 √3 N m

Lub cim ntxiv vim tias lub zog F ua rau lub beam tig counterclockwise.

[irp]

3. Qhov ntev ntawm ib lub beam yog 2 m. Qhov loj ntawm F ₁ yog 10 N thiab qhov loj ntawm F ₂ yog 15 N. Txheeb xyuas qhov net torque nyob ib ncig ntawm qhov chaw ntawm lub beam.

Lub axis ntawm kev sib hloov ntawm qhov chaw ntawm lub beam.

Paub:

Lub zog 1 (F ₁ ) = 10 N

Qhov deb ntawm F ₁ thiab qhov chaw nruab nrab ntawm lub teeb (r ₁ ) = 1 m

Lub caj npab 1 (l ₁ ) = r ₁ sin 90 ^o = (1 m)(1) = 1 m

Lub zog F1 _yog perpendicular rau lub beam.

Lub zog 2 (F ₂ ) = 15 N

Qhov nrug ntawm F2 _thiab qhov chaw nruab nrab ntawm lub beam (r2 ₎ = 1 m

Lub zog F2 _yog perpendicular rau lub beam.

Lub caj npab 2 (l ₂ ) = r ₁ sin 90 ^o = (1 m)(1) = 1 m

Xav tau: Lub zog torque nyob ib ncig ntawm lub axis ntawm kev sib hloov

Tshuaj:

Lub zog torque 1:

τ ₁ = F ₁ l ₁ = (10 N)( 1 m) = 10 N m

Lub cim ntxiv vim tias lub zog ntawm F ₁ ua rau lub beam tig counterclockwise.

Lub zog torque 2:

τ ₂ = F ₂ l ₂ = (15 N)( 1 m) = -15 N

Lub cim rho tawm vim tias lub zog F2 _ua rau lub beam tig mus rau sab laug.

Lub zog net:

luas = τ ₁ – τ ₂ = 10 – 15 = – 5 N m

Lub cim rho tawm yog vim tias lub beam tig clockwise.

[irp]

4. Qhov ntev ntawm lub beam AB yog 2 m, qhov loj ntawm F ₁ yog 10 N thiab qhov loj ntawm F ₂ yog 10 N. Txheeb xyuas qhov net torque nyob ib ncig ntawm qhov chaw ntawm lub beam.

Lub axis ntawm kev sib hloov ntawm qhov chaw ntawm lub beam.

Paub:

Lub zog 1 (F ₁ ) = 10 Nn

Qhov nrug ntawm F1 _thiab qhov chaw nruab nrab ntawm lub beam (r1 ₎ = 1 m

Lub caj npab 1 (l ₁ ) = r ₁ sin 60 ^o = (1 m)(0.5 √3 ) = 0.5 √3 m

Lub zog 2 (F ₂ ) = 10 N

Qhov nrug ntawm F2 _thiab qhov chaw nruab nrab ntawm lub beam (r2 ₎ = 1 m

Lub zog F2 _yog perpendicular rau lub beam.

Lub caj npab 2 (l ₂ ) = r ₂ sin 90 ^o = (1 m)(1) = 1 m

Xav tau: Lub zog net torque nyob ib ncig ntawm lub axis ntawm kev sib hloov

Tshuaj:

Lub zog torque 1:

τ ₁ = F ₁ l ₁ = (10 N)( 0.5 √3 m) = 5 √3 = 8.7 Nm

Lub cim ntxiv vim tias lub zog F ₁ ua rau lub beam tig mus rau sab laug.

Lub zog torque 2:

τ ₂ = F ₂ l ₂ = (10 N)( 1 m) = -10 N m

Lub cim rho tawm vim tias lub zog F2 _ua rau lub beam tig mus rau sab laug.

Lub zog net:

luas = τ ₁ – τ ₂ = 8.7 – 10 = – 1.3 N m

Lub cim rho tawm vim tias lub zog ua rau lub beam tig mus rau sab xis.

[irp]

5. Qhov ntev ntawm ib lub beam yog 10 m, qhov loj ntawm F ₁ yog 10 N, qhov loj ntawm F ₂ yog 10 N thiab qhov loj ntawm F ₃ yog 15 N. Qhov deb ntawm qhov chaw A thiab qhov chaw C yog 7.5 m. Lub zog F ₂ nyob rau hauv nruab nrab ntawm lub beam. Txheeb xyuas qhov net torque txog qhov chaw C nyob ntawm 2.5 m ntawm qhov chaw B.

Lub axis ntawm kev sib hloov yog nyob ntawm qhov chaw C

Paub:

Lub zog 1 (F ₁ ) = 10 N

Qhov nrug ntawm F1 _thiab taw tes C (r1 ₎ = 2.5 m

Lub zog F1 _yog perpendicular rau lub beam.

Lub caj npab ntawm tus pas nrig 1 (l ₁ ) = r ₁ sin 90 ^o = ( 2.5 m)( 1 ) = 2.5 m

Lub zog 2 (F ₂ ) = 10 N

Qhov nrug ntawm F2 _thiab taw tes C (r2 ₎ = 2.5 m

Lub zog F2 _yog perpendicular rau lub beam.

Lub caj npab 2 (l ₂ ) = r ₂ sin 90 ^o = ( 2.5 m)(1) = 2.5 m

Lub zog 3 (F ₃ ) = 15 N

Qhov nrug ntawm F3 _thiab taw tes C (r3 ₎ = 7.5 m

Lub zog F3 _yog perpendicular rau lub beam.

Lub caj npab 3 (l ₃ ) = r ₃ sin 90 ^o = (7.5 m)(1) = 7.5 m

Xav tau: Lub zog net torque nyob ib ncig ntawm lub axis ntawm kev sib hloov

Tshuaj:

Lub zog torque 1:

τ ₁ = F ₁ l ₁ = (10 N)( 2.5 m) = 25 N m

Lub cim ntxiv vim tias lub zog F ₁ ua rau lub beam tig mus rau sab laug.

Lub zog torque 2:

τ ₂ = F ₂ l ₂ = (10 N)( 2.5 m) = 25 N m

Lub cim ntxiv vim tias lub zog F2 _ua rau lub nqaj tig mus rau sab laug.

Lub zog torque 3:

τ ₃ = F ₃ l ₃ = (15 N)( 7.5 m) = -112..5 N m

Lub cim rho tawm vim tias lub zog F3 _ua rau lub beam tig mus rau sab laug.

Lub zog net:

luas = τ ₁ + τ ₂ - τ ₃ = 25 + 25 - 112.5 = - 62.5 N m

Lub cim rho tawm vim tias lub zog ua rau lub beam tig mus rau sab xis.

[irp]

6. Qhov ntev ntawm ib lub beam yog 10 m, qhov loj ntawm F₁ yog 10 N, qhov loj ntawm F₂ yog 10 N thiab qhov loj ntawm F₃ yog 10 N. Txheeb xyuas lub zog net torque txog qhov chaw A, nyob 5 m ntawm qhov chawnt ntawm kev siv lub zog F₁.

Lub axis ntawm kev tig ntawm qhov chaw A.

Paub:

Lub zog 1 (F ₁ ) = 10 N

Qhov nrug ntawm F1 _thiab taw tes A (r1 ₎ = 5 m

Lub caj npab 1 (l ₁ ) = r ₁ sin 60 ^o = (5 m)(0.5 √3 ) = 2.5 √3 m

Lub zog 2 (F2 ₎ = 10 N

Qhov nrug ntawm F2 _thiab taw tes A (r2 ₎ = 0

Lub zog F2 _yog perpendicular rau lub beam.

Lub caj npab 2 (l2 ₎ = r2 _sin90 o ⁼ (0)(1) = 0

Lub zog 3 (F3 ₎ = 10 N

Qhov nrug ntawm F3 _thiab taw tes A (r3 ₎ = 10 m

Lub caj npab 3 (l ₃ ) = r ₃ sin 30 ^o = (10 m)(0.5) = 5 m

Xav tau: lub net torque nyob ib ncig ntawm lub axis ntawm kev sib hloov

Tshuaj:

Lub zog torque 1:

τ ₁ = F ₁ l ₁ = (10 N)( 2.5 √3 m ) = 25√3 = 43.3 N m

Lub cim ntxiv vim tias lub zog F ₁ ua rau lub beam tig mus rau sab laug.

Lub zog torque 2:

τ ₂ = F ₂ l ₂ = (10 N)(0) = 0

Lub zog torque 3:

τ ₃ = F ₃ l ₃ = (10 N)( 5 m) = -50 N m

Lub cim rho tawm vim tias lub zog F3 _ua rau lub beam tig mus rau sab laug.

Lub zog net:

luas = τ ₁ + τ ₂ - τ ₃ = 43.3 + 0 - 50 = - 6.7 N m

Lub cim rho tawm vim tias lub zog ua rau lub beam tig mus rau sab xis.

nyeem ntxiv

1. Ib yam khoom hnyav 500-gram , A, txav mus rau 10 m/s thiab ib yam khoom hnyav 200-gram, B, txav mus rau 12 m/s. Cov khoom no txav mus ze ib leeg thiab sib tsoo. Yog tias qhov ceev ntawm yam khoom A tom qab sib tsoo yog 6 m/s, qhov ceev ntawm yam khoom B tom qab sib tsoo yog dab tsi?

Paub:

Qhov hnyav ntawm yam khoom 1 (m ₁ ) = 500 grams = 0.5 kg

Qhov hnyav ntawm yam khoom 2 (m2 ₎ = 200 grams = 0.2 kg

Qhov ceev pib ntawm yam khoom 1 (v ₁ ) = -10 m/s

Qhov ceev pib ntawm yam khoom 2 (v ₂ ) = 12 m/s

Qhov ceev kawg ntawm yam khoom 1 (v ₁ ') = 6 m/s

Cov cim ntxiv thiab cov cim tsis qhia qhia tias cov khoom txav mus rau qhov sib txawv.

Xav tau : qhov ceev kawg ntawm yam khoom 2 (v ₂ ')

Tshuaj:

m₁ v₁ +m₂ v₂ = kuv₁ v₁' + m₂ v₂'

(0.5)(-10) + (0.2)(12) = (0.5)(6) + (0.2)(v ₂ ')

-5 + 2.4 = 3 + 0.2 v ₂ '

-2.6 = 3 + 0.2 v ₂ '

-2.6 – 3 = 0.2 v ₂ '

-5.6 = 0.2 v ₂ '

v ₂ ' = -5.6 / 0.2

v ₂ ' = -28 m/s

Qhov ceev ntawm yam khoom 2 tom qab sib tsoo yog 28 m/s.

Cov cim ntxiv thiab rho tawm qhia tias cov khoom txav mus rau sab nraud.

[irp]

2. Ob yam khoom sib npaug zos los ze rau ib leeg thiab sib tsoo. Qhov ceev ntawm yam khoom 1 yog 6 m/s thiab qhov ceev ntawm yam khoom 2 yog 8 m/s. Tom qab sib tsoo, yam khoom 2 txav mus rau sab laug nrog qhov ceev ntawm 5 m/s. Qhov loj thiab qhov kev coj ntawm qhov ceev ntawm yam khoom 1 tom qab sib tsoo yog dab tsi?

Paub:

Qhov hnyav ntawm yam khoom 1 (m ₁ ) = m

Qhov hnyav ntawm yam khoom 2 (m2 ₎ = m

Qhov ceev pib ntawm yam khoom 1 (v ₁ ) = -6 m/s

qhov ceev pib ntawm yam khoom 2 (v ₂ ) = 8 m/s

Qhov ceev kawg ntawm yam khoom 2 (v ₂ ') = -5 m/s

Xav tau : qhov loj thiab kev coj ntawm yam khoom 1 tom qab kev sib tsoo

Tshuaj:

Cov qauv ntawm kev txuag ntawm linear momentum :

m₁ v₁ +m₂ v₂ = kuv₁ v₁' + m₂ v₂'

mv ₁ + m v ₂ = m v ₁ ' + m v ₂ '

m (v ₁ + v ₂ ) = m (v ₁ ' + v ₂ ' )

v ₁ + v ₂ = v ₁ ' + v ₂ '

-6 + 8 = v1 _' – 5

2 = v1 _' – 5

2 + 5 = _v1 '

v ₁ ' = 7 m/s

Qhov ceev ntawm yam khoom 1 tom qab sib tsoo (v ₁ ') yog 3 m/s.

Cov cim ntxiv thiab rho tawm qhia tias cov khoom txav mus rau sab nraud.

[irp]

3. Lub pob 1-kg thiab lub pob 2-kg muaj tib qho kev taw qhia thiab sib tsoo tsis sib luag. Ua ntej sib tsoo, lub pob 1 txav nrog qhov ceev ntawm 10 m/s thiab lub pob 2 txav nrog qhov ceev ntawm 5 m/s. Qhov ceev ntawm lub pob 2 tom qab sib tsoo yog 4 m/s. Txheeb xyuas qhov ceev ntawm lub pob 1 tom qab sib tsoo.

Paub:

Qhov hnyav ntawm lub pob 1 (m1 ₎ = 1 kg

Qhov hnyav ntawm lub pob 2 (m2 ₎ = 2 kg

Qhov ceev ntawm lub pob 1 (v ₁ ) = 10 m/s

Qhov ceev ntawm lub pob 2 (v ₂ ) = 5 m/s

Qhov ceev kawg ntawm lub pob 2 (v ₂ ') = 4 m/s

Lub cim ntxiv ntawm qhov ceev qhia tias cov pob muaj tib qho kev taw qhia.

Xav tau : qhov ceev kawg ntawm lub pob 1 (v ₁ ')

Tshuaj:

m₁ v₁ +m₂ v₂ = kuv₁ v₁' + m₂ v₂'

(1)(10) + (2)(5) = (1)(v ₁ ') + (2)(4)

10 + 10 = v1 _' + 8

20 – 8 = v ₁ '

v ₁ ' = 12 m/s

Qhov ceev ntawm lub pob 1 tom qab sib tsoo yog 12 m/s.

[wpdm_package id='1190′]

1. Cov teeb meem thiab kev daws teeb meem ntawm linear momentum
2. Cov teeb meem thiab kev daws teeb meem ntawm lub zog thiab lub zog txav mus los
3. Kev sib tsoo zoo kawg nkaus hauv ib qho teeb meem thiab kev daws teeb meem
4. Kev sib tsoo tsis sib xws hauv ib qho teeb meem thiab kev daws teeb meem
5. Kev sib tsoo tsis sib xws hauv ib qho teeb meem thiab kev daws teeb meem

nyeem ntxiv

1. Ib lub mos txwv hnyav 30-gram uas txav mus los ntawm 30 m/s sib tsoo nrog ib lub thaiv hnyav 1-kg thaum so. Txheeb xyuas qhov ceev ntawm lub thaiv yog tias lub mos txwv thiab lub thaiv xauv ua ke vim yog qhov kev sib tsoo.

Paub:

Qhov hnyav ntawm lub mos txwv (m ₁ ) = 30 grams = 0.03 kg

Qhov hnyav ntawm lub thaiv (m2 ₎ = 1 kg

Qhov ceev pib ntawm lub mos txwv ( v ₁ ) = 30 m/s

qhov ceev pib ntawm lub block (v ₂ ) = 0 ( block thaum so )

Xav tau : qhov ceev ntawm lub mos txwv thiab thaiv tom qab sib tsoo (v')

Tshuaj:

m ₁ v ₁ + m ₂ v ₂ = (m ₁ + m ₂ ) v'

(0.03)(30) + (1)(0) = (0.03 + 1) v'

0.9 + 0 = 1.03 v'

0.9 = 1,03 v'

v' = 0.9 / 1,03

v' = 0.87 m/s

[irp]

2. Lub pob Billiard A uas hnyav 2 kg txav nrog qhov ceev v _A = 6 ms ⁻¹ tsoo taub hau nrog lub pob B uas hnyav sib npaug. Yog tias qhov kev sib tsoo tsis sib luag, qhov ceev ntawm ob lub pob tom qab kev sib tsoo yog dab tsi.

Paub:

Qhov hnyav A (mA ₎ = 2 kg

Qhov hnyav B (mB ₎ = 2 kg

Qhov ceev pib ntawm lub pob A (v _A ) = -6 m/s

Qhov ceev pib ntawm lub pob B (v _B ) = 4 m/s

Cov cim ntxiv thiab cov cim tsis qhia qhia tias cov khoom txav mus rau qhov sib txawv.

Xav tau : qhov ceev ntawm ob lub pob tom qab kev sib tsoo. (v')

Tshuaj:

m _A v _A + m _B v _B = (m _A ' + m _B ) v'

(2)(-6) + (2)(4) = (2 + 2) v'

-12 + 8 = 4 v'

-4 = 4 v'

v' = -4 / 4

v' = -1 m/s

[irp]

3. m₁ = 3 kg thiab m₂ = 4 kg mus txog ib leeg rau ib leeg hauv kev taw qhia sib txawv nrog kev nrawm ntawm v₁ = 10 m/s thiab v₂ = 12 m/s. Yog tias qhov kev sib tsoo tsis muaj zog kiag li, qhov ceev ntawm ob lub pob tom qab kev sib tsoo yog dab tsi.

Paub:

Qhov hnyav ntawm yam khoom 1 (m1 ₎ = 3 kg

Qhov hnyav ntawm yam khoom 2 (m2 ₎ = 4 kg

Qhov ceev ntawm yam khoom 1 (v ₁ ) = -10 m/s

Qhov ceev ntawm yam khoom 2 (v ₂ ) = 12 m/s

Xav tau : qhov ceev tom qab sib tsoo (v')

Tshuaj:

m ₁ v ₁ + m ₂ v ₂ = (m ₁ ' + m ₂ ) v'

(3)(-10) + (4)(12) = (3 + 4) v'

-30 + 48 = 7 v'

18 = 7 v'

v' = 18 / 7

v' = 2.6 m/s

[wpdm_package id='1157′]

1. Cov teeb meem thiab kev daws teeb meem ntawm linear momentum
2. Cov teeb meem thiab kev daws teeb meem ntawm lub zog thiab lub zog txav mus los
3. Kev sib tsoo zoo kawg nkaus hauv ib qho teeb meem thiab kev daws teeb meem
4. Kev sib tsoo tsis sib xws hauv ib qho teeb meem thiab kev daws teeb meem
5. Kev sib tsoo tsis sib xws hauv ib qho teeb meem thiab kev daws teeb meem

nyeem ntxiv

1. Ib lub pob A hnyav 200-gram, txav mus los ntawm qhov ceev 10 m/s, ntaus lub pob B hnyav 200-gram, thaum so. Qhov ceev ntawm lub pob A thiab lub pob B tom qab sib tsoo yog dab tsi?

Paub:

Qhov hnyav ntawm lub pob A (m _A ) = 200 grams = 0.2 kg

Qhov hnyav ntawm lub pob B (mB ₎ = 200 grams = 0.2 kg

Qhov ceev ntawm lub pob A ua ntej sib tsoo (v _A ) = 10 m/s

Qhov ceev ntawm lub pob B ua ntej sib tsoo (v _B ) = 0

Xav tau: qhov ceev ntawm lub pob A (v _A ') thiab qhov ceev ntawm lub pob B (v _B ') tom qab kev sib tsoo

Tshuaj:

v _A ' = v _B = 0

vB _' = vA ₌ 10 m/s

[irp]

2. Ob yam khoom uas muaj qhov hnyav sib npaug zos los ze rau ib leeg, sib tsoo thiab tom qab ntawd dhia tawm. Qhov ceev ntawm qhov hnyav A ua ntej sib tsoo yog 8 m/s thiab qhov ceev ntawm qhov hnyav B ua ntej sib tsoo yog 12 m/s. Qhov loj thiab qhov kev coj ntawm qhov ceev ntawm qhov hnyav A thiab qhov hnyav B tom qab sib tsoo yog dab tsi!

Paub:

Qhov hnyav A (m _A ) = m

Qhov hnyav B (mB ₎ = m

Qhov ceev ntawm pawg A ua ntej sib tsoo (v _A ) = -8 m/s

Qhov ceev ntawm pawg B ua ntej sib tsoo (v _B ) = 12 m/s

Cov cim ntxiv thiab rho tawm qhia tias cov khoom txav mus rau sab nraud.

Xav tau: qhov loj thiab kev coj ntawm qhov ceev ntawm pawg A (v _A ') thiab pawg B (v _B ') tom qab kev sib tsoo

Tshuaj:

Hauv kev sib tsoo zoo kawg nkaus elastic, yog tias cov khoom muaj qhov hnyav sib npaug ces qhov ceev ntawm A tom qab kev sib tsoo (v _A ') = qhov ceev ntawm B ua ntej kev sib tsoo (v _B ) thiab qhov ceev ntawm B tom qab kev sib tsoo (v _B ') = qhov ceev ntawm A ua ntej kev sib tsoo (v _A ).

Yog tias ua ntej sib tsoo, A txav mus rau sab xis thiab B txav mus rau sab laug, ces, tom qab sib tsoo, A txav mus rau sab laug thiab B txav mus rau sab xis.

Cov khoom muaj qhov hnyav sib npaug thiab qhov kev sib tsoo yog elastic zoo kawg nkaus yog li ob qho khoom sib pauv qhov ceev.

v _A ' = -v _B = -12 m/s

vB _' = vA ₌ 8 m/s

Cov cim ntxiv thiab rho tawm qhia tias cov khoom txav mus rau sab nraud.

[irp]

3. Ib yam khoom hnyav 2-kg, A, txav mus nrog qhov ceev 10 m/s, ntaus ib lub pob hnyav 4-kg, B, txav mus nrog qhov ceev 20 m/s. Yog tias qhov kev sib tsoo yog elastic zoo kawg nkaus, qhov ceev ntawm yam khoom A thiab yam khoom B yog dab tsi tom qab kev sib tsoo?

Paub:

Qhov hnyav A (mA ₎ = 2 kg

Qhov hnyav B (mB ₎ = 4 kg

Qhov ceev ntawm yam khoom A ua ntej sib tsoo (v _A ) = 10 m/s

Qhov ceev ntawm yam khoom B ua ntej sib tsoo (v _B ) = 20 m/s

Xav tau : qhov ceev ntawm yam khoom A (v _A ') thiab qhov ceev ntawm yam khoom B (v _B ') tom qab sib tsoo

Kev daws teeb meem :

Hauv kev sib tsoo zoo kawg nkaus elastic , yog tias cov khoom muaj qhov hnyav sib npaug thiab mus ze rau ib leeg, qhov ceev ntawm cov khoom tom qab sib tsoo raug suav los ntawm kev siv cov mis no:

Qhov ceev ntawm yam khoom A tom qab kev sib tsoo:

[irp]

4. Ib yam khoom hnyav 100-gram txav mus los ntawm 20 m/s tsoo ib phab ntsa uas sib tsoo tau zoo heev. Qhov loj thiab qhov kev coj ntawm qhov ceev ntawm yam khoom tom qab sib tsoo yog dab tsi.

Paub:

Qhov hnyav (mA ₎ = 100 grams = 0.1 kg

Qhov hnyav ntawm phab ntsa (mB ₎ = infinity

Qhov ceev ntawm pawg ua ntej sib tsoo (v _A ) = 20 m/s

Qhov ceev ntawm pawg tom qab sib tsoo (v _B ) = 0

Xav tau : qhov loj thiab kev coj ntawm qhov ceev tom qab sib tsoo

Tshuaj:

Yog tias v _B = 0, m _A me heev thiab m2 _loj heev ces v _A ' = -v _A thiab v2 _' = 0.

Cov cim ntxiv thiab rho tawm qhia tias cov khoom txav mus rau sab nraud.

5. Ob lub pob, A nrog qhov hnyav ntawm 2-kg thiab pob B nrog qhov hnyav ntawm 5-kg, ua ntej thiab tom qab kev sib tsoo tau qhia nyob rau hauv daim duab hauv qab no. Yog tias kev sib tsoo yog elastic zoo kawg nkaus, qhov ceev ntawm lub pob A ua ntej kev sib tsoo yog dab tsi?

Paub:

Qhov hnyav ntawm lub pob Ib (m_A) = 2 kg

Qhov hnyav ntawm lub pob B (mB ₎ = 5 kg

Qhov ceev ntawm lub pob B ua ntej sib tsoo (v _B ) = 2 m/s

Qhov ceev ntawm lub pob A tom qab sib tsoo (v _A ') = 5 m/s

Qhov ceev ntawm lub pob B tom qab sib tsoo (v _B ') = 4 m/s

Ob lub pob txav mus rau sab xis yog li lawv qhov ceev kos npe zoo.

Xav tau: Qhov ceev ntawm lub pob A ua ntej sib tsoo (v _A )

Tshuaj:

m_A v_A +m_B v_B = kuv_A v_A' + m_B v_B'

2(v _A ) + (5)(2) = (2)(5) + (5)(4)

2(vA ₎ + 10 = 10 + 20

2(vA ₎ + 10 = 30

2(vA ₎ = 30 – 10

2(vA ₎ = 20

vA = _20/2

v _A = 10 m/s

[irp]

6. Cov khoom A thiab B taug kev raws txoj kab rov tav, raws li pom hauv daim duab hauv qab no. Yog tias qhov kev sib tsoo yog qhov elastic zoo kawg nkaus thiab qhov ceev ntawm cov khoom B tom qab kev sib tsoo yog 15 m/s ¹ , qhov ceev ntawm cov khoom A tom qab kev sib tsoo yog dab tsi.

Paub:

Qhov hnyav ntawm yam khoom Ib (m_A) = 5 kg

Qhov hnyav ntawm yam khoom B (mB ₎ = 2 kg

Qhov ceev ntawm yam khoom A ua ntej sib tsoo (v _A ) = 12 m/s

Qhov ceev ntawm yam khoom B ua ntej sib tsoo (v _B ) = 10 m/s

Qhov ceev ntawm yam khoom B tom qab sib tsoo (v _B ') = 15 m/s

Ob qho khoom, ua ntej thiab tom qab sib tsoo, txav mus rau sab xis kom lawv qhov ceev kos npe zoo.

Xav tau: Qhov ceev ntawm yam khoom A tom qab sib tsoo (v _A ')

Tshuaj:

m_A v_A +m_B v_B = kuv_A v_A' + m_B v_B'

(5)(12) + (2)(10) = (5)v _A ' + (2)(15)

60 + 20 = (5)v _A ' + 30

80 = (5)v _A ' + 30

80 – 30 = (5)v _A '

50 = (5)v _A '

v _A ' = 50/5

v _A ' = 10 m/s

[wpdm_package id='1156′]

1. Cov teeb meem thiab kev daws teeb meem ntawm linear momentum
2. Cov teeb meem thiab kev daws teeb meem ntawm lub zog thiab lub zog txav mus los
3. Kev sib tsoo zoo kawg nkaus hauv ib qho teeb meem thiab kev daws teeb meem
4. Kev sib tsoo tsis sib xws hauv ib qho teeb meem thiab kev daws teeb meem
5. Kev sib tsoo tsis sib xws hauv ib qho teeb meem thiab kev daws teeb meem

nyeem ntxiv

1. Muab ib lub pob me me pov rau kab rov tav nrog qhov ceev tas li ntawm 10 m/s. Lub pob ntaus phab ntsa thiab cuam tshuam nrog tib qhov ceev. Qhov kev hloov pauv ntawm lub zog linear ntawm lub pob yog dab tsi?

Paub:

Qhov hnyav (m) = 0.2 kg

Qhov ceev pib ( _v₂o ) = -10 m/s

Qhov ceev kawg (v _t ) = 10 m/s

Cov cim ntxiv thiab cov cim tsis qhia qhia tias cov khoom txav mus rau qhov sib txawv.

Xav tau : qhov kev hloov pauv ntawm lub zog linear (Δp)

Tshuaj:

Cov qauv ntawm kev hloov pauv ntawm linear momentum :

Δp = mv _t – mv _o = m (v _t – v _o )

Kev hloov pauv ntawm lub zog linear:

Δp = 0.2 (10 – (-10)) = 0.2 (10 + 10)

Δp = 0.2 (20)

Δp = 4 kg m/s

[irp]

2. Ib lub pob 10-gram poob dawb paug los ntawm qhov siab, ntaus hauv pem teb ntawm 15 m/s, ces rov cuam tshuam rau saum ntuj ntawm 10 m/s. Txheeb xyuas lub zog!

Paub:

Qhov hnyav (m) = 10 grams = 0.01 kg

Qhov ceev pib ( _v₂o ) = -15 m/s

Qhov ceev kawg (v _t ) = 10 m/s

Xav tau: Impulse (I)

Tshuaj:

Lub zog (I) sib npaug rau qhov kev hloov pauv ntawm lub zog (Δp)

I = mv _t – mv _o = m (v _t – v _o )

Lub zog ua ntej:

Kuv = 0.01 (10 – (-15)) = 0.01 (10 + 15)

Kuv = 0.01 (25)

Kuv = 0.25 kg m/s

[irp]

3. Muab pov ib lub pob hnyav 200-gram rau ntawm kab rov tav nrog qhov ceev ntawm 4 m/s, ces lub pob raug ntaus rau tib qho kev taw qhia. Lub sijhawm uas lub pob kov nrog tus ntaus pob yog 2 mais ib vib nas this thiab qhov ceev ntawm lub pob tom qab tawm hauv tus ntaus pob yog 12 m/s. Lub zog loj ntawm tus ntaus pob siv rau ntawm lub pob yog ...

Paub:

Qhov hnyav (m) = 200 grams = 0.2 kg

Qhov ceev pib ( _v₂o ) = 4 m/s

Qhov ceev kawg (v _t ) = 12 m/s

Lub sijhawm luv (t) = 2 milliseconds = (2/1000) vib nas this = 0.002 vib nas this

Xav tau : Qhov loj ntawm lub zog (F)

Tshuaj:

Cov qauv ntawm lub zog:

Kuv = Ft

Tus qauv ntawm kev hloov pauv ntawm momentum:

mv _t – mv _o = m (v _t – v _o )

Lub zog (I) sib npaug rau qhov kev hloov pauv ntawm lub zog (Δp)

Kuv = Δp

Ft = m ( _vt – _vo )

F (0.002) = (0.2)(12 – 4)

F (0.002) = (0.2)(8)

F (0.002) = 1.6

F = 1.6 / 0.002

F = 800 Newtons

[wpdm_package id='1155′]

1. Cov teeb meem thiab kev daws teeb meem ntawm linear momentum
2. Cov teeb meem thiab kev daws teeb meem ntawm lub zog thiab lub zog txav mus los
3. Kev sib tsoo zoo kawg nkaus hauv ib qho teeb meem thiab kev daws teeb meem
4. Kev sib tsoo tsis sib xws hauv ib qho teeb meem thiab kev daws teeb meem
5. Kev sib tsoo tsis sib xws hauv ib qho teeb meem thiab kev daws teeb meem

nyeem ntxiv

1. Ib yam khoom khiav nrawm li ntawm 10 m/s tas li. Xam lub zog ntawm yam khoom ntawd.

Paub :

Qhov hnyav (m) = 1 kg

Qhov ceev (v) = 10 m/s

Xav tau: lub zog linear (p)

Tshuaj:

Cov qauv ntawm lub zog linear:

p = mv

p = linear momentum, m = mass, v = velocity

Lub zog linear:

p = mv = (1)(10) = 10 kg m/s ²

[irp]

2. Ib lub thaiv 2-kg thiab ib lub thaiv 4-kg txav mus los ntawm qhov ceev tas li 20 m/s. Lub zog ntawm cov thaiv yog dab tsi?

Paub:

Qhov hnyav ntawm thaiv A (m _A ) = 2 kg

Qhov hnyav ntawm thaiv B (mB ₎ = 4 kg

Qhov ceev ntawm thaiv A (v _A ) = 20 m/s

Qhov ceev ntawm thaiv B (v _B ) = 20 m/s

Xav tau: Lub zog linear ntawm block A (p _A ) thiab lub zog linear ntawm block B (p _B )

Tshuaj:

Lub zog linear ntawm thaiv A :

p _A = m _A v _A = (2)(20) = 40 kg m/s

Lub zog ntawm lub block B :

p _B = m _B v _B = (4)(20) = 80 kg m/s

[irp]

3. Ib lub thaiv 2-kg txav ntawm qhov ceev tas li 2 m/s thiab ib lub thaiv 2-kg txav ntawm qhov ceev tas li 4 m/s. Txheeb xyuas lub zog linear ntawm cov thaiv.

Paub:

Qhov hnyav ntawm thaiv A (m _A ) = 2 kg

Qhov hnyav ntawm thaiv B (mB ₎ = 2 kg

Qhov ceev ntawm thaiv A (v _A ) = 2 m/s

Qhov ceev ntawm thaiv B (v _B ) = 4 m/s

Xav tau: lub zog linear ntawm cov blocks

Tshuaj:

Lub zog linear ntawm thaiv A :

p _A = m _A v _A = (2)(2) = 4 kg m/s

Lub zog linear ntawm thaiv B:

p _B = m _B v _B = (2)(4) = 8 kg m/s

[irp]

4. Ib yam khoom hnyav 5-kg uas so. Lub zog ntawm lub zog ntawd yog dab tsi?

Paub:

Qhov hnyav (m) = 5 kg

Qhov ceev ntawm yam khoom (v) = 0

Xav tau : lub zog linear (p)

Tshuaj:

p = mv = (5)(0) = 0

[wpdm_package id='1155′]

1. Cov teeb meem thiab kev daws teeb meem ntawm linear momentum
2. Cov teeb meem thiab kev daws teeb meem ntawm lub zog thiab lub zog txav mus los
3. Kev sib tsoo zoo kawg nkaus hauv ib qho teeb meem thiab kev daws teeb meem
4. Kev sib tsoo tsis sib xws hauv ib qho teeb meem thiab kev daws teeb meem
5. Kev sib tsoo tsis sib xws hauv ib qho teeb meem thiab kev daws teeb meem

nyeem ntxiv

Lub zog yog qhov nrawm uas ua haujlwm tiav hauv ib lub sijhawm. Hauv kev suav lej, lub zog yog qhov sib piv ntawm kev ua haujlwm/lub sijhawm.

P = W/t

Kev piav qhia: P = lub zog (Joule/ob = Watt), W = ua haujlwm (Joule), t = lub sijhawm luv (ob)

Raws li qhov sib npaug no, nws tuaj yeem xaus lus tias qhov ua haujlwm ntau dua, lub zog ntau dua. Ntawm qhov tod tes, qhov ua haujlwm me dua, lub zog me dua. Kev ua haujlwm txhais tau tias qhov ua haujlwm tiav.

[irp]

Lub zog yog ib qho scalar. Chav SI ntawm lub zog yog Joule/ob. Joule/ob = Watt (luv ua W), hu ua li ntawd los ua kev hwm rau James Watt. Chav imperial Askiv rau lub zog yog foot-pounds ib ob.

Lub tshuab no me dhau rau kev siv tau, yog li ntawd, siv lub zog loj dua (hu ua hp). Ib lub zog = 550 foot-pounds ib ob = 764 Watts = ¾ kilowatt.

Tus nqi ntawm txoj haujlwm kuj tseem tuaj yeem qhia ua lub zog x lub sijhawm, piv txwv li, kilowatt-teev lossis kWh. Ib kWh txhais tau tias txoj haujlwm ua tiav ntawm tus nqi tas li ntawm 1 kiloWatt rau ib teev.

1. Ib tug neeg hnyav 50-kg khiav nce ntaiv siab 10 meters hauv 2 feeb. Kev nrawm vim lub ntiajteb txawj nqus (g) yog 10 m/ s ^2. Txheeb xyuas lub zog.

Paub:

Qhov hnyav (m) = 50 kg

Qhov siab (h) = 10 meters

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

Lub sijhawm luv (t) = 2 feeb = 2 (60) = 120 vib nas this

Xav tau : Lub zog (P)

Tshuaj:

Tus qauv ntawm lub zog:

P = W / t

P = zog , W = ua haujlwm , t = sijhawm

Tus qauv ua haujlwm:

W = F s = wh = mgh

W = ua haujlwm , F = lub zog , w = qhov hnyav , d = kev hloov chaw , h = qhov siab , m = pawg, g = kev nrawm vim yog lub ntiajteb txawj nqus

W = mgh = (50)(10)(10) = 5000 Joules.

P = W / t = 5000 / 120 = 41.7 Joules/se c rau d.

[irp]

2. Xam lub zog uas ib tug neeg hnyav 60-kg xav tau uas nce ib tsob ntoo siab 5 meters hauv 10 vib nas this. Kev nrawm vim lub ntiajteb txawj nqus yog 10 m/s ².

Paub:

Qhov hnyav (m) = 60 kg

Qhov siab (h) = 5 meters s

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

Lub sijhawm luv (t) = 10 vib nas this

Xav tau : Lub zog

Tshuaj:

Ua Haujlwm:

W = mgh = (60)(10)(5) = 3000 Joules

Lub hwj chim:

P = W / t = 3000 / 10 = 300 Joules/se cond.

3. Ib lub tshuab ua yeeb yam rotary uas muaj zog 300 watts thiab lub sijhawm tig 5 feeb. Lub zog uas nws siv yog….

A. 15 kJ

B. 75 kJ

C. 90 kJ

D. 450 kJ

Paub:

Lub zog (P) = 300 Watts = 300 Joules/ob

Lub Sijhawm (T) = 5 feeb = 5 (60 vib nas this) = 300 vib nas this

Tus naj npawb ntawm kev tig = 5

Xav tau: Lub zog siv los ntawm kev ua yeeb yam rotary

Tshuaj:

Cov lus teb yog D.

[wpdm_package id='1190′]

1. Ua haujlwm tau ua tiav los ntawm kev siv zog teeb meem thiab kev daws teeb meem
2. Cov teeb meem thiab kev daws teeb meem ntawm lub zog ua haujlwm-kinetic
3. Cov teeb meem thiab kev daws teeb meem ntawm lub hauv paus ntsiab lus ntawm lub zog ua haujlwm-mechanical
4. Cov teeb meem thiab kev daws teeb meem ntawm lub zog gravitational
5. Lub zog muaj peev xwm ntawm cov teeb meem caij nplooj ntoos hlav elastic thiab kev daws teeb meem
6. Teeb meem fais fab thiab kev daws teeb meem
7. Kev siv ntawm kev txuag lub zog mechanical rau kev txav mus los dawb
8. Kev siv ntawm kev txuag lub zog kho tshuab rau kev txav mus rau saum thiab nqis hauv kev txav mus los dawb
9. Kev siv ntawm kev txuag lub zog kho tshuab rau kev txav mus los ntawm qhov chaw nkhaus
10. Kev siv ntawm kev txuag lub zog kho tshuab rau kev txav mus los ntawm lub dav hlau inclined
11. Kev siv ntawm kev txuag lub zog kho tshuab rau kev txav mus los ntawm projectile

nyeem ntxiv

1. Ib lub thaiv swb rau ntawm ib lub dav hlau du thiab tsis muaj kev sib txhuam . Qhov ceev ntawm lub thaiv thaum nws tsoo hauv av yog dab tsi. Kev nrawm vim lub ntiajteb txawj nqus yog 10 m/s ²

Paub:

Qhov siab (h) = 8 m

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

Xav tau : qhov ceev (v)

Kev daws teeb meem :

Lub zog pib kho tshuab (ME _o ) = lub zog gravitational (PE)

ME ₌ PE = mgh = m (10)(8) = 80 m

Lub zog tshuab kawg (ME _t ) = lub zog kinetic (KE)

ME _t = KE = ½ mv ²

Lub hauv paus ntsiab lus ntawm kev txuag lub zog tshuab hais tias lub zog tshuab pib = lub zog tshuab kawg:

KUV ₌ KUV _t

80 m = ½ mv ²

80 = ½ v ²

160 = ^v2

v = √160 = √(16)(10) = 4√10 m/s

[irp]

2. Ib yam khoom hnyav 1-kg swb nqes mus raws 8 meters. Txheeb xyuas lub zog kinetic tom qab yam khoom txav mus raws 5 meters… Kev nrawm vim lub ntiajteb txawj nqus g = 10 m/s ²

Paub:

Qhov hnyav (m) = 0.2 kg

d = 5 meters

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

Xav tau : lub zog kinetic (KE)

Tshuaj:

sin 30 ^o = h / d

0.5 = h / 5

h = (0.5)(5) = 2.5 meters

Qhov kev hloov pauv ntawm qhov siab ntawm cov khoom yog 2.5 meters.

Lub zog pib kho tshuab (ME _o ) = lub zog gravitational potential (PE)

ME ₌ PE = mgh = (1)(10)(2.5) = 25 Joules

Lub zog kho tshuab kawg (ME _t ) = lub zog kinetic (KE)

ME _t = KE

Lub hauv paus ntsiab lus ntawm kev txuag lub zog tshuab hais tias lub zog tshuab pib = lub zog tshuab kawg:

KUV ₌ KUV _t

25 = KE

Lub zog Kinetic = 25 Joules.

[wpdm_package id='1170′]

1. Cov teeb meem thiab kev daws teeb meem ntawm lub zog ua haujlwm
2. Cov teeb meem thiab kev daws teeb meem ntawm lub zog ua haujlwm-kinetic
3. Cov teeb meem thiab kev daws teeb meem ntawm lub hauv paus ntsiab lus ntawm lub zog ua haujlwm-mechanical
4. Cov teeb meem thiab kev daws teeb meem ntawm lub zog gravitational
5. Lub zog muaj peev xwm ntawm cov teeb meem caij nplooj ntoos hlav elastic thiab kev daws teeb meem
6. Teeb meem fais fab thiab kev daws teeb meem
7. Kev siv ntawm kev txuag lub zog mechanical rau kev txav mus los dawb
8. Kev siv ntawm kev txuag lub zog kho tshuab rau kev txav mus rau saum thiab nqis hauv kev txav mus los dawb
9. Kev siv ntawm kev txuag lub zog kho tshuab rau kev txav mus los ntawm qhov chaw nkhaus
10. Kev siv ntawm kev txuag lub zog kho tshuab rau kev txav mus los ntawm lub dav hlau inclined
11. Kev siv ntawm kev txuag lub zog kho tshuab rau kev txav mus los ntawm projectile

nyeem ntxiv

1. Ib lub thaiv hnyav 1-kg swb rau ntawm qhov chaw du thiab nkhaus. Txheeb xyuas lub zog kinetic thiab qhov ceev ntawm lub thaiv ntawm qhov chaw qis tshaj plaws. Kev nrawm vim lub ntiajteb txawj nqus yog 10 m/s ².

Paub:

Qhov hnyav (m) = 1 kg

Qhov kev hloov pauv ntawm qhov siab (h) = 5 m

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

Xav tau: Lub zog Kinetic (KE) thiab qhov ceev ntawm lub block.

Tshuaj:

(a) Lub zog Kinetic

Lub zog pib ntawm lub tshuab = lub zog gravitational

ME ₌ PE = mgh = (1)(10)(5) = 50 Joules

Lub zog tshuab kawg = lub zog kinetic

ME _t = KE = ½ mv _t ²

Lub hauv paus ntsiab lus ntawm kev txuag lub zog tshuab hais tias lub zog tshuab pib = lub zog tshuab kawg:

KUV ₌ KUV _t

PE = KE

50 = KE

Lub zog Kinetic (KE) = 50 Joules.

(b) Qhov ceev ntawm lub thaiv

Lub hauv paus ntsiab lus ntawm kev txuag lub zog tshuab:

Lub zog kho tshuab pib (ME _o ) = lub zog kho tshuab kawg (ME _t )

Lub zog muaj peev xwm ntawm lub ntiajteb txawj nqus (PE) = lub zog kinetic (KE)

50 = ½ mv ²

2(50) / m = ^v2

100 / 1 = ^v2

100 = ^v2

v = √100

v = 10 m/s

[irp]

2. Ib yam khoom hnyav 2-kg swb nqes los yam tsis muaj kev sib txhuam. Lub zog kinetic thiab qhov ceev ntawm yam khoom ntawm 2 meters saum av yog dab tsi? Kev nrawm vim lub ntiajteb txawj nqus yog 10 m/s ²

Paub:

Qhov hnyav (m) = 2 kg

Qhov kev hloov ntawm qhov siab (h) = 10 – 2 = 8 m

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

Xav tau : lub zog kinetic (KE) thiab qhov ceev (v) ntawm 2 meters saum av.

Tshuaj:

(a) Lub zog Kinetic ntawm 2 meters saum av

Lub zog pib ntawm lub tshuab = lub zog gravitational

ME ₌ PE = mgh = (2)(10)(8) = 160 Joules

Lub zog tshuab kawg = lub zog kinetic

ME _t = KE = ½ mv _t ²

Lub hauv paus ntsiab lus ntawm kev txuag lub zog tshuab hais tias lub zog tshuab pib = lub zog tshuab kawg:

KUV ₌ KUV _t

PE = KE

160 = KE

Lub zog Kinetic (KE) ntawm 2 meters saum av yog 160 Joules.

(b) Qhov ceev ntawm yam khoom ntawm qhov chaw qis tshaj plaws

Lub hauv paus ntsiab lus ntawm kev txuag lub zog kho tshuab:

Lub zog kho tshuab pib (ME _o ) = lub zog kho tshuab kawg (EM _t )

Lub zog muaj peev xwm ntawm lub ntiajteb txawj nqus (PE) = lub zog kinetic (KE)

160 = ½ mv ²

160 = ½ (2) ntawm ²

160 = ^v2

v = √160 = √(16)(10) = 4√10 m/s

[wpdm_package id='1167′]

1. Cov teeb meem thiab kev daws teeb meem ntawm lub zog ua haujlwm
2. Cov teeb meem thiab kev daws teeb meem ntawm lub zog ua haujlwm-kinetic
3. Cov teeb meem thiab kev daws teeb meem ntawm lub hauv paus ntsiab lus ntawm lub zog ua haujlwm-mechanical
4. Cov teeb meem thiab kev daws teeb meem ntawm lub zog gravitational
5. Lub zog muaj peev xwm ntawm cov teeb meem caij nplooj ntoos hlav elastic thiab kev daws teeb meem
6. Teeb meem fais fab thiab kev daws teeb meem
7. Kev siv ntawm kev txuag lub zog mechanical rau kev txav mus los dawb
8. Kev siv ntawm kev txuag lub zog kho tshuab rau kev txav mus rau saum thiab nqis hauv kev txav mus los dawb
9. Kev siv ntawm kev txuag lub zog kho tshuab rau kev txav mus los ntawm qhov chaw nkhaus
10. Kev siv ntawm kev txuag lub zog kho tshuab rau kev txav mus los ntawm lub dav hlau inclined
11. Kev siv ntawm kev txuag lub zog kho tshuab rau kev txav mus los ntawm projectile

nyeem ntxiv

1. Ib lub pob ncaws pob uas raug ncaws tawm hauv av ntawm lub kaum sab xis θ = 30 ^o nrog qhov ceev pib ntawm 10 m/s. Lub pob qhov hnyav = 0.1 kg. Kev nrawm vim yog lub ntiajteb txawj nqus yog 1 0 m/s ^2. Txheeb xyuas (a) Lub zog muaj peev xwm ntawm lub ntiajteb txawj nqus ntawm qhov chaw siab tshaj plaws (b) Qhov chaw siab tshaj plaws lossis qhov siab tshaj plaws

Paub:

Qhov hnyav (m) = 0.1 kg

Qhov ceev pib ( _v₂o ) = 10 m/s

Lub kaum sab xis = 30 ^o

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

Tshuaj:

(a) Lub zog muaj peev xwm ntawm lub ntiajteb txawj nqus

Xam qhov feem kab rov tav (v _ox ) thiab feem ntsug (v _oy ) ntawm qhov ceev pib.

v_ox = v_o cos θ = (10)(cos 30^o) = (10)(0.5√3) = 5√3 m/s

v _oy = v _o sin θ = (10)(sin 30 ^o ) = (10)( 0.5) = 5 m/s

Lub zog pib ntawm lub tshuab

Lub zog pib kho tshuab (ME _o ) = lub zog kinetic (KE)

ME _o = KE = ½ mv _o ² = ½ (0.1)(10) ² = ½ (0.1)(100) = ½ (10) = 5 Joules

Lub zog kho tshuab kawg

Lub zog Kinetic ntawm qhov siab tshaj plaws:

KE = ½ mv _ox ² = ½ (0.1)(5√3) ² = ½ (0.1)((25)(3)) = ½ (0.1)(75) = 3.75 Joules

Lub hauv paus ntsiab lus ntawm kev txuag lub zog tshuab

Lub zog kho tshuab pib (ME _o ) = lub zog kho tshuab kawg (ME _t )

KE = PE + KE

5 = EP + 3.75

PE = 5 – 3.75 = 1.25 Joule

Lub zog muaj peev xwm ntawm lub ntiajteb txawj nqus ntawm qhov chaw siab tshaj plaws yog 1.25 Joules.

(b) Qhov siab tshaj plaws lossis qhov siab tshaj plaws

PE = mg/h

1.25 = (0.1)(10) teev

1.25 = teev

Qhov siab tshaj plaws yog 1.25 meters.

[irp]

2. Ib lub pob 0.1-kg raug tso tawm kab rov tav nrog qhov ceev pib v _o = 10 m/s ntawm lub tsev siab 10 meters. Kev nrawm vim lub ntiajteb txawj nqus yog 10 m/s ^2. Txheeb xyuas lub zog kinetic ntawm lub pob thaum nws ntaus hauv av.

Paub:

Qhov hnyav (m) = 0.1 kg

Qhov ceev pib ( _v₂o ) = 10 m/s

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

Qhov kev hloov ntawm qhov siab (h) = 10 – 2 = 8 m

Xav tau: lub zog kinetic ntawm 2 meters saum av

Tshuaj:

Lub zog muaj peev xwm ntawm lub ntiajteb txawj nqus (PE) = mgh = (0.1)(10)(10) = 10 Joules

Lub zog pib ntawm lub zog (KE) = ½ mv _o ² = ½ (0.1)(10) ² = ½ (0.1)(100) = ½ (10) = 5 Joules

Lub zog kinetic kawg = lub zog gravitational thawj zaug + lub zog kinetic thawj zaug = 10 + 5 = 15 Joules

[wpdm_package id='1173′]

1. Cov teeb meem thiab kev daws teeb meem ntawm lub zog ua haujlwm
2. Cov teeb meem thiab kev daws teeb meem ntawm lub zog ua haujlwm-kinetic
3. Cov teeb meem thiab kev daws teeb meem ntawm lub hauv paus ntsiab lus ntawm lub zog ua haujlwm-mechanical
4. Cov teeb meem thiab kev daws teeb meem ntawm lub zog gravitational
5. Lub zog muaj peev xwm ntawm cov teeb meem caij nplooj ntoos hlav elastic thiab kev daws teeb meem
6. Teeb meem fais fab thiab kev daws teeb meem
7. Kev siv ntawm kev txuag lub zog mechanical rau kev txav mus los dawb
8. Kev siv ntawm kev txuag lub zog kho tshuab rau kev txav mus rau saum thiab nqis hauv kev txav mus los dawb
9. Kev siv ntawm kev txuag lub zog kho tshuab rau kev txav mus los ntawm qhov chaw nkhaus
10. Kev siv ntawm kev txuag lub zog kho tshuab rau kev txav mus los ntawm lub dav hlau inclined
11. Kev siv ntawm kev txuag lub zog kho tshuab rau kev txav mus los ntawm projectile

nyeem ntxiv