Muaj ob hom kev siv zog: muaj peev xwm thiab muaj zog kinetic. Lub zog muaj peev xwm yog lub zog txheeb ze uas ib yam khoom muaj kev hwm rau txoj haujlwm ntawm lwm yam khoom. Piv txwv li, yog tias koj nyob saum toj siab, koj muaj peev xwm muaj peev xwm ntau dua li yog koj nyob ntawm taw roob. Kinetic zog yog lub zog uas ib yam khoom muaj thaum nws txav mus. Lub zog hluav taws xob tuaj yeem tsim tawm vim kev co, kev hloov pauv, lossis kev txhais lus (txav los ntawm ib qhov chaw mus rau lwm qhov). Lub zog hluav taws xob ntawm txhua yam khoom tuaj yeem nrhiav tau yooj yim los ntawm qhov sib npaug uas siv qhov hnyav thiab nrawm ntawm cov khoom ntawd.
Kauj ruam
Ntu 1 ntawm 3: Nkag Siab Kinetic Zog
Kauj Ruam 1. Paub cov mis rau xam cov kinetic zog
Cov mis rau xam lub zog hluav taws xob (EK) yog EK = 0.5 x mv2. Hauv qhov kev ua zauv no, m sawv cev rau qhov hnyav, uas yog qhov teeb meem ntawm qhov khoom, thiab v sawv cev rau qhov khoom nrawm lossis tus nqi uas cov khoom hloov pauv txoj haujlwm.
Koj cov lus teb yuav tsum tau sau ua joules (J), uas yog chav ntsuas ntawm kev ntsuas rau lub zog kinetic. Joule yog sib npaug rau 1 kg * m2/s2.
Kauj Ruam 2. Txiav txim siab qhov hnyav ntawm qhov khoom
Yog tias koj daws qhov teeb meem uas tsis paub qhov hnyav, koj yuav tsum txiav txim siab qhov hnyav ntawm koj tus kheej. Tus nqi ntawm qhov hnyav tuaj yeem txiav txim siab los ntawm qhov hnyav ib yam khoom ntawm qhov ntsuas thiab pom nws qhov hnyav hauv kilograms (kg).
- Coj cov nplai. Ua ntej koj ntsuas koj cov khoom, koj yuav tsum txo cov nplai. Zeroing nplai hu ua pej thuam.
- Muab koj cov khoom tso rau ntawm qhov ntsuas. Maj mam tso cov khoom ntawm qhov ntsuas thiab sau nws qhov hnyav hauv kilograms.
- Yog tias tsim nyog, hloov cov gram mus rau kilograms. Txog qhov suav zaum kawg, qhov hnyav yuav tsum yog kilograms.
Kauj Ruam 3. Xam cov khoom nrawm
Ntau zaus, qhov teeb meem yuav ua rau tus kwv nrawm dua. Yog tias tsis yog, koj tuaj yeem pom nws qhov nrawm los ntawm kev siv qhov kev ncua deb ntawm cov khoom mus thiab lub sijhawm nws siv cov khoom mus rau qhov deb ntawd. Chav tsev ceev yog meters ib ob (m/s).
- Kev nrawm nrawm tau txhais raws qhov kev ua zauv raws li kev hloov pauv los ntawm lub sijhawm: V = d/t. Tshaj tawm yog qhov muaj nuj nqis vector, piv txwv li nws muaj ob qho loj thiab qhov taw qhia. Qhov loj yog tus lej tus lej uas sawv cev rau qhov nrawm, thaum qhia yog qhov kev taw qhia uas qhov kev nrawm nrawm mus.
- Piv txwv li, qhov nrawm ntawm qhov khoom tuaj yeem yog 80 m/s lossis -80 m/s, nyob ntawm qhov kev taw qhia uas nws tau txav mus los.
- Txhawm rau suav qhov nrawm, yooj yim faib qhov kev ncua deb uas ib yam khoom tau taug kev los ntawm lub sijhawm nws siv cov khoom los npog qhov nrug ntawd.
Ntu 2 ntawm 3: Xam Kinetic Zog
Kauj Ruam 1. Sau kab zauv
Cov mis rau xam lub zog hluav taws xob (EK) yog EK = 0.5 x mv2. Hauv qhov kev ua zauv no, m sawv cev rau qhov hnyav, uas yog qhov teeb meem ntawm qhov khoom, thiab v sawv cev rau qhov khoom nrawm lossis tus nqi uas cov khoom hloov pauv txoj haujlwm.
Koj cov lus teb yuav tsum tau sau ua joules (J), uas yog tus qauv ntsuas ntawm kev ntsuas lub zog kinetic. Joule yog sib npaug rau 1 kg * m2/s2.
Kauj Ruam 2. Plug qhov loj thiab qhov nrawm rau hauv qhov sib npaug
Yog tias koj tsis paub qhov hnyav lossis nrawm ntawm qhov khoom, tom qab ntawd koj yuav tsum suav nws. Piv txwv tias koj paub qhov loj ntawm ob qhov sib txawv thiab tab tom sim daws qhov teeb meem hauv qab no: Txiav txim siab lub zog ntawm cov poj niam 55 kg uas tab tom khiav ntawm 3.87 m/s. Txij li thaum koj paub tus poj niam qhov hnyav thiab nrawm, koj tuaj yeem ntsaws qhov txiaj ntsig rau hauv qhov sib npaug:
- EK = 0.5 x mv2
- EK = 0.5 x 55 x (3,87)2
Kauj Ruam 3. Daws qhov sib npaug
Thaum koj nkag mus rau qhov hnyav thiab nrawm, koj tuaj yeem pom lub zog kinetic (EK). Square tus tshaj tawm thiab muab txhua qhov sib txawv. Nco ntsoov sau koj cov lus teb hauv joules (J).
- EK = 0.5 x 55 x (3,87)2
- EK = 0.5 x 55 x 14.97
- EK = 411,675 J
Ntu 3 ntawm 3: Siv Lub Hwj Huam Kinetic los Nrhiav Kev Tshaj Tawm lossis Loj
Kauj Ruam 1. Sau kab zauv
Cov mis rau xam lub zog hluav taws xob (EK) yog EK = 0.5 x mv2. Hauv qhov kev ua zauv no, m sawv cev rau qhov hnyav, uas yog qhov teeb meem ntawm qhov khoom, thiab v sawv cev rau qhov khoom nrawm lossis tus nqi uas cov khoom hloov pauv txoj haujlwm.
Koj cov lus teb yuav tsum tau sau ua joules (J), uas yog chav ntsuas ntawm kev ntsuas rau lub zog kinetic. Joule yog sib npaug rau 1 kg * m2/s2.
Kauj Ruam 2. Nkag mus paub qhov sib txawv
Hauv qee qhov teeb meem, koj tuaj yeem paub lub zog hluav taws xob thiab huab hwm coj lossis lub zog hluav taws xob thiab nrawm. Thawj kauj ruam los daws qhov teeb meem no yog nkag mus rau txhua qhov paub uas txawv.
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Piv txwv 1: Qhov nrawm ntawm qhov khoom hnyav li 30 kg nrog lub zog siv hluav taws xob ntawm 500 J yog dab tsi?
- EK = 0.5 x mv2
- 500 J = 0.5 x 30 x v2
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Piv txwv 2: Dab tsi yog qhov hnyav ntawm cov khoom uas muaj lub zog siv hluav taws xob ntawm 100 J thiab nrawm ntawm 5 m/s?
- EK = 0.5 x mv2
- 100 J = 0.5 x m x 52
Kauj Ruam 3. Rov kho qhov sib npaug los daws qhov tsis paub sib txawv
Siv algebra, koj tuaj yeem pom tus nqi ntawm qhov sib txawv tsis paub los ntawm kev rov kho dua txhua qhov kev paub sib txawv mus rau ib sab ntawm qhov sib npaug.
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Piv txwv 1: Qhov nrawm ntawm qhov khoom hnyav li 30 kg nrog lub zog siv hluav taws xob ntawm 500 J yog dab tsi?
- EK = 0.5 x mv2
- 500 J = 0.5 x 30 x v2
- Sib npaug qhov loj los ntawm 0.5: 0.5 x 30 = 15
- Faib cov kinetic zog los ntawm cov khoom: 500/15 = 33, 33
- Square hauv paus kom pom qhov nrawm: 5.77 m/s
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Piv txwv 2: Dab tsi yog qhov hnyav ntawm cov khoom uas muaj lub zog siv hluav taws xob ntawm 100 J thiab nrawm ntawm 5 m/s?
- EK = 0.5 x mv2
- 100 J = 0.5 x m x 52
- Square ceev: 52 = 25
- Muab xam los ntawm 0, 5: 0, 5 x 25 = 12, 5
- Faib cov kinetic zog los ntawm cov khoom: 100/12, 5 = 8 kg
