Kev sib tsoo ntawm cov khoom hu ua kev sib tsoo zoo kawg nkaus elastic yog tias lub zog thiab lub zog kinetic ntawm txhua yam khoom ua ntej kev sib tsoo zoo ib yam li lub zog thiab lub zog kinetic ntawm txhua yam khoom tom qab kev sib tsoo. Hauv lwm lo lus, kev sib tsoo elastic zoo meej siv tau. txoj cai ntawm kev txuag lub zog thiab txoj cai ntawm kev txuag lub zog kinetic. Kev siv lo lus elastic qhia tias tom qab kev sib tsoo, ob yam khoom tsis sib koom ua ib qho lossis lo ua ke tab sis dhia.
Lub zog ntawm txhua yam khoom raug khaws cia:
Lub zog kinetic ntawm txhua yam khoom raug khaws cia:
Kev sib tsoo uas zoo tag nrho yuav tsum tsis muaj suab nrov thiab tsis tsim cua sov vim muaj kev sib txhuam ntawm cov khoom sib tsoo. Yog tias kev sib tsoo ntawm ob yam khoom tsim suab thiab cua sov, ces lub zog kinetic ntawm cov khoom tsis raug khaws cia. Ntxiv rau kev hloov pauv mus ua suab thiab cua sov, qee lub zog kinetic raug hloov pauv mus ua lub zog sab hauv. Ib qho piv txwv ntawm kev sib tsoo uas zoo tag nrho yog kev sib tsoo ntawm cov khoom me me atomic thiab subatomic.
Hauv qhov teeb meem sib tsoo zoo kawg nkaus, yog tias qhov ceev pib paub tab sis qhov ceev kawg tsis paub, qhov teeb meem yuav tsis daws tau los ntawm kev siv cov qauv 1.5 thiab 1.6 xwb. Yog li ntawd, ob qho qauv saum toj no raug kho dua kom tau txais lwm qhov qauv uas siv tau los txiav txim qhov ceev kawg.
Tshem tawm qhov factor ½ thiab tom qab ntawd hloov kho qhov equation 1.6.
Kev tswj hwm ntawm kab zauv 1.5
Faib kab zauv 1.7 los ntawm kab zauv 1.8 kom tau txais qhov tshwm sim kawg.
Cov qauv 1.5 thiab 1.9 siv tau los daws cov teeb meem sib tsoo uas zoo sib xws. Muab cov qauv 1.5 thiab 1.9 ua ke kom tau ob qho qauv los txiav txim siab qhov ceev kawg ntawm ob yam khoom yog tias tsuas yog paub lawv qhov hnyav thiab qhov ceev pib xwb.
Thaum daws cov teeb meem siv cov qauv saum toj no, siv lub cim raug rau v.1 thiab v2Yog tias yam khoom 1 txav mus rau sab xis ces v1 zoo yog tias yam khoom 2 txav mus rau sab laug ces v2 tsis zoo. Yog tias ob yam khoom txav mus rau hauv qhov sib txawv tab sis qhov kev taw qhia ntawm kev txav mus los tsis piav qhia ces v1 thiab v2 yuav tsum tau muab ib lub cim txawv, piv txwv li v1 zoo thiab v2 tsis zoo.
1. Qhov hnyav ntawm ob yam khoom yog tib yam
Yog tias m1 = kuv2 ces v1' = v2 thiab v2' = v1.
Yog tias ob yam khoom txav mus rau sab nraud, ua li cas? Piv txwv li, yog tias ua ntej kev sib tsoo, yam khoom 1 txav mus rau sab xis thiab yam khoom 2 txav mus rau sab laug, tom qab kev sib tsoo, yam khoom 1 txav mus rau sab laug (v1' = – v2) thiab yam khoom 2 txav mus rau sab xis (v2' = v1).
Yog tias ib yam khoom tseem nyob twj ywm thaum xub thawj? Piv txwv li, yog tias ua ntej kev sib tsoo, ob yam khoom tseem nyob twj ywm (v2 = 0) ces tom qab qhov khoom sib tsoo 1 tseem nyob (v)1' = 0) thiab yam khoom 2 txav mus rau tib qhov ceev li qhov ceev pib ntawm yam khoom 1 (v2' = v1). Yog tias ua ntej kev sib tsoo, yam khoom 1 txav mus rau sab xis, tom qab ntawd tom qab kev sib tsoo, yam khoom 2 txav mus rau sab xis. Yog li ob yam khoom sib pauv qhov ceev.
Piv txwv teeb meem.
1. Ob yam khoom A (2 kg) thiab B (2 kg) txav mus rau sab nraud nrog qhov ceev ntawm 4 m/s thiab 2 m/s. Yog tias yam khoom A sib tsoo nrog yam khoom B hauv txoj kev ywj pheej zoo kawg nkaus, qhov ceev kawg ntawm yam khoom A thiab yam khoom B yog dab tsi?
Kev Sib Tham
Nws yog paub :
mA = 2 kg, mB = 2 kg
vA = 4 m/s, vB = -2 m/s
Nug : nyob rau hauvA'thiab vB'
Jawb :
vA' = -2 m/s thiab vB' = 4 m/s
Tom qab kev sib tsoo, khoom A txav mus nrog qhov ceev ntawm 2 m/s thiab khoom B txav mus nrog qhov ceev ntawm 4 m/s, qhov twg qhov kev taw qhia ntawm kev txav mus los ntawm ob yam khoom yog qhov sib txawv. Yog tias ua ntej kev sib tsoo, khoom A txav mus rau sab xis thiab khoom B txav mus rau sab laug, tom qab kev sib tsoo, khoom A txav mus rau sab laug thiab khoom B txav mus rau sab xis.
2. Khoom A (2 kg) txav mus rau sab xis nrog qhov ceev 2 m/s thiab tsoo nrog khoom B (2 kg) uas tseem nyob. Yog tias ob yam khoom sib tsoo yooj yim, qhov ceev kawg ntawm khoom A thiab khoom B yog dab tsi?
Kev Sib Tham
Nws yog paub :
mA = 2 kg, mB = 2 kg
vA = 2 m/s, vB = 0 m/s
Nug : nyob rau hauvA'thiab vB'
Jawb :
vA' = 0 thiab vB' = 2 m/s
Tom qab kev sib tsoo, yam khoom A tseem nyob twj ywm thiab yam khoom B txav mus rau sab xis ntawm qhov ceev ntawm 2 m/s.
2. Qhov hnyav ntawm ob yam khoom sib txawv
Yog tias ob yam khoom muaj qhov ceev pib thiab qhov hnyav sib txawv (qhov sib txawv me me), ces qhov ceev kawg paub los ntawm kev siv cov qauv 1.10 thiab 1.11.
Yog tias thaum xub thawj yam khoom 2 tsis txav (v2 = 0) ces kab zauv 1.10 hloov mus rau kab zauv 1.12 thiab kab zauv 1.11 hloov mus rau kab zauv 1.13.
Yog tias v2 = 0, m1 loj heev, m2 me me heev ces los ntawm kev daws cov kab zauv 1.12 thiab 1.13 peb tau txais v1' = v1 thiab v2' = 2v1Yog tias v2 = 0, m1 me me heev, m2 loj heev, yog li ntawd los ntawm kev daws cov kab zauv 1.12 thiab 1.13 peb tau txais v1' = -v1 thiab v2' = 0. Cov cim zoo thiab tsis zoo qhia txog kev txav mus los ntawm cov khoom mus rau sab nraud.
Piv txwv teeb meem.
1. Ib yam khoom uas hnyav 1 kg txav mus los ntawm qhov ceev 20 m/s ntaus phab ntsa kom sib zog. Qhov ceev kawg ntawm yam khoom thiab phab ntsa yog dab tsi?
Kev Sib Tham
Nws yog paub :
mA = 1 kg, vA = 20 m/s, mB = loj heev thiab vB = 0
Nug : nyob rau hauvA'thiab vB'
Jawb :
vA' = -20 m/s
vB' = 0
Tom qab kev sib tsoo, yam khoom A dhia nrog qhov ceev ntawm 20 m/s thiab yam khoom B tseem nres. Yog tias ua ntej kev sib tsoo yam khoom A txav mus rau sab xis, ces tom qab kev sib tsoo yam khoom A txav mus rau sab laug.
