Yuav Ua Li Cas Thiaj Li Nruab Nrab Qhov Ceev: 10 Kauj Ruam (nrog Duab)

2024 Tus sau: Jason Gerald | [email protected]. Kawg hloov kho: 2024-01-19 22:12

Kev nrawm yog tus nqi uas piav qhia kev hloov pauv nrawm, suav nrog kev hloov pauv. Koj tuaj yeem pom qhov nrawm nrawm kom pom qhov nrawm nrawm ntawm cov khoom dhau ib lub sijhawm. Txij li qhov no tsis yog qee yam uas tib neeg suav rau hauv lub neej txhua hnub, cov teeb meem nrawm tuaj yeem yog qhov txawv txav. Txawm li cas los xij, nrog txoj hauv kev raug koj tuaj yeem nkag siab cov teeb meem no sai.

Kauj ruam

Ntu 1 ntawm 2: Xam Nruab Nrab Qhov Ceev

Kauj Ruam 1. Nkag siab tias kev nrawm yog dab tsi

Kev nrawm piav qhia ceev npaum li cas qee yam ua nrawm lossis qeeb. Lub tswv yim yog qhov yooj yim heev qhov tseeb, txawm hais tias koj phau ntawv ua lej piav qhia nrawm li "kev hloov pauv hauv lub sijhawm dhau los." Kev nrawm kuj piav qhia txog qhov twg qee yam txav mus, uas koj tuaj yeem suav nrog ua cov lus piav qhia lossis yog ib feem ntawm kev suav:

• Feem ntau, yog tias yam khoom tau nrawm mus rau sab xis, nce, lossis mus rau tom ntej, tib neeg sau qhov nrawm nrawm raws li tus lej zoo (+).
• Yog tias ib yam khoom tau nrawm sab laug, nqis, lossis rov qab, siv tus lej tsis zoo (-) los sau qhov nrawm.

Kauj Ruam 2. Sau lub ntsiab lus ntawm kev ua kom nrawm raws li tus lej

Raws li tau piav qhia saum toj no, nrawm yog hloov pauv ceev nyob rau ib lub sijhawm. Muaj ob txoj hauv kev los sau tus lej nrawm:

• a_{ua av} = ^v/_t (Lub cim lossis "delta" txhais tau tias "hloov pauv.")
• a_{ua av} = ^{(v_f -v_kuv)}/_{(tf - tkuv)} Hauv qhov sib npaug no, v_f yog qhov nrawm tshaj plaws, thiab v_kuv yog thawj zaug tshaj tawm.

Kauj Ruam 3. Nrhiav qhov nrawm thiab zaum kawg ntawm ib yam khoom

Piv txwv li, yog tias lub tsheb nres ntawm ib sab ntawm txoj kev pib txav ntawm 500 m/s mus rau sab xis, nws pib nrawm yog 0 m/s, thiab nws qhov nrawm kawg yog 500 m/s rau sab xis.

• Txij tam sim no, peb yuav siv tus lej zoo los piav qhia kev txav mus rau sab xis, yog li peb tsis tas yuav teeb tsa cov lus qhia txhua lub sijhawm.
• Yog tias lub tsheb pib txav mus rau tom ntej tab sis xaus rau kev txav rov qab, nco ntsoov sau qhov nrawm kawg hauv tus lej tsis zoo.

Kauj Ruam 4. Sau lub sijhawm hloov pauv

Piv txwv li, lub tsheb yuav siv sijhawm 10 vib nas this kom mus txog nws qhov nrawm kawg. Muaj qhov tshwj xeeb thaum lo lus nug hais tias qee yam txawv, qhov no feem ntau txhais tau tias t_f = 10 vib nas this thiab t_kuv = 0 feeb.

Xyuas kom tseeb tias koj qhov nrawm thiab sijhawm tau sau rau hauv cov chav sib xws. Piv txwv li, yog tias koj qhov nrawm sau hauv mais ib teev, lub sijhawm yuav tsum sau ua teev ib yam

Kauj Ruam 5. Siv cov lej no los xam qhov nrawm nrawm

Hauv peb qhov piv txwv:

• a_{ua av} = ^{(500 m/s - 0 m/s)}/_{(10s - 0s)}
• a_{ua av} = ^(500m/s)/_(10s)
• a_{ua av} = 50 m/s/s Qhov no tseem tuaj yeem sau ua 50 m/s².

Kauj Ruam 6. Nkag siab cov txiaj ntsig

Qhov nruab nrab nrawm piav qhia txog kev hloov pauv nrawm npaum li cas lub sijhawm peb tab tom sim, qhov nruab nrab. Hauv qhov piv txwv saum toj no, lub tsheb tau txav mus rau sab xis, thiab txhua ob lub tsheb tau nrawm dua los ntawm qhov nruab nrab ntawm 50 m/s. Nco tseg tias cov ntsiab lus ntawm kev txav chaw yuav hloov pauv, tsuav yog lub tsheb nres nrog tib qho kev hloov pauv nrawm thiab hloov pauv raws sijhawm:

• Lub tsheb tuaj yeem pib ntawm 0 m/s thiab nrawm ntawm qhov nrawm tsis tu ncua li 10 vib nas this, kom txog thaum lub tsheb mus txog 500 m/s.
• Lub tsheb tuaj yeem pib ntawm 0 m/s, nrawm dua 900 m/s, tom qab ntawd qeeb mus rau 500 m/s ntawm 10 vib nas this.
• Lub tsheb tuaj yeem pib ntawm 0 m/s, nyob twj ywm rau 9 vib nas this, tom qab ntawd dhia mus rau qhov nrawm ntawm 500 m/s nrawm heev ntawm kaum thib ob.

Ntu 2 ntawm 2: Nkag Siab Qhov Zoo thiab Tsis Ceev Ceev

Kauj Ruam 1. Paub tias qhov zoo thiab qhov tsis zoo sawv cev rau qhov twg

Thaum qhov nrawm ib txwm hais qhia kev taw qhia, nws tuaj yeem dhau mus ua qhov sau "nce" lossis "sab qaum teb" lossis "mus rau ntawm phab ntsa." Txawm li cas los xij, feem ntau cov teeb meem lej yuav xav tias cov khoom txav raws txoj kab ncaj. Tsiv mus rau hauv ib qho kev taw qhia ntawm kab tau piav raws li qhov nrawm (+), kev txav mus rau qhov kev coj rov qab yog qhov tsis zoo (-).

Piv txwv li, lub tsheb ciav hlau xiav tau txav mus rau sab hnub tuaj ntawm 500 m/s. Lub tsheb ciav hlau liab tab tom txav mus rau sab hnub poob sai dua, tab sis vim tias lub tsheb ciav hlau liab tau txav mus rau lwm qhov los ntawm lub tsheb ciav hlau xiav, lub tsheb ciav hlau liab txav ntawm -500 m/s

Kauj Ruam 2. Siv lub ntsiab lus ntawm kev nrawm los txiav txim qhov + lossis - kos npe

Kev nrawm yog kev hloov pauv nrawm hauv lub sijhawm. Yog tias koj tsis meej pem txog seb yuav sau qhov nrawm lossis tsis zoo, ua tibzoo saib qhov kev hloov pauv nrawm thiab pom cov txiaj ntsig:

v_kawg -v_pib = + los yog -?

Kauj Ruam 3. Nkag siab lub ntsiab lus ntawm kev nrawm nrawm hauv txhua qhov kev coj

Piv txwv tias lub tsheb ciav hlau xiav thiab lub tsheb ciav hlau liab tau txav mus rau hauv cov lus qhia sib txawv ntawm qhov nrawm ntawm 5 m/s. Peb tuaj yeem piav qhia qhov no ntawm tus lej kab, nrog lub tsheb ciav hlau xiav txav ntawm +5 m/s raws qhov zoo ntawm tus lej kab, thiab lub tsheb ciav hlau liab txav ntawm -5 m/s raws qhov tsis zoo. Yog tias txhua lub tsheb ciav hlau pib nrawm dua kom txog thaum lub tsheb ciav hlau nrawm dua 2 m/s hauv kev taw qhia lub tsheb ciav hlau txav mus los, txhua lub tsheb ciav hlau muaj qhov nrawm lossis tsis zoo? Cia saib:

• Lub tsheb ciav hlau xiav tau txav nrawm dua ntawm qhov zoo, yog li qhov ceev ntawm lub tsheb ciav hlau xiav nce ntawm +5 m/s txog +7 m/s. Qhov nrawm tshaj tawm qhov pib tshaj tawm yog 7 - 5 = +2. Txij li qhov kev hloov pauv nrawm yog qhov zoo, kev nrawm kuj tseem zoo.
• Lub tsheb ciav hlau liab txav nrawm dua raws qhov tsis zoo, yog li lub tsheb ciav hlau pib ntawm -5 m/s tab sis xaus li -7 m/2. Qhov kawg tshaj tawm qhov pib tshaj tawm yog -7 -(-5) = -7 + 5 = -2 m/s. Txij li qhov kev hloov pauv nrawm yog qhov tsis zoo, yog li qhov nrawm.

Kauj Ruam 4. Nkag siab tias nws txhais li cas kom qeeb

Piv txwv tias lub dav hlau pib txav ntawm 500 mais ib teev, tom qab ntawd qeeb mus txog 400 mais ib teev. Txawm hais tias lub dav hlau tseem tab tom txav mus rau qhov zoo lossis mus rau tom ntej, kev nrawm ntawm lub dav hlau tsis zoo, vim tias lub dav hlau tau txav mus qeeb qeeb dua li ua ntej. Koj tuaj yeem tshawb xyuas tib txoj hauv kev raws li qhov piv txwv saum toj no: 400 - 500 = -100, yog li qhov nrawm nrawm tsis zoo.

Lub caij no, yog lub nyoob hoom qav taub txav ntawm -100 mais toj ib teev thiab nce mus rau -50 mais ib teev, lub dav hlau tau ntsib qhov nrawm dua. Qhov no yog vim qhov kev hloov pauv nrawm tshwm sim hauv qhov kev coj ua zoo: -50 -(-100) = +50, txawm hais tias qhov kev hloov pauv tsis txaus los thim rov qab ntawm lub dav hlau