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′]
- Cov teeb meem thiab kev daws teeb meem ntawm linear momentum
- Cov teeb meem thiab kev daws teeb meem ntawm lub zog thiab lub zog txav mus los
- Kev sib tsoo zoo kawg nkaus hauv ib qho teeb meem thiab kev daws teeb meem
- Kev sib tsoo tsis sib xws hauv ib qho teeb meem thiab kev daws teeb meem
- Kev sib tsoo tsis sib xws hauv ib qho teeb meem thiab kev daws teeb meem
