4 Piv txwv ntawm qhov nruab nrab ntawm qhov ceev thiab qhov nruab nrab ntawm qhov ceev
1. Ib lub tsheb khiav ncaj nraim mus rau sab hnub tuaj li 100 meters hauv 4 vib nas this thiab tom qab ntawd khiav ncaj nraim mus rau sab hnub poob li 50 meters hauv 1 vib nas this. Txheeb xyuas seb qhov ceev nruab nrab dan qhov ceev nruab nrab txawb tau.
Kev Sib Tham
Qhov Nrug = 100 meters + 50 meters = 150 meters
Qhov ntau ntawm kev hloov chaw = 100 meters - 50 meters = 50 meters thiab qhov kev hloov chaw yog mus rau sab hnub tuaj.
Tag nrho lub sijhawm = 4 vib nas this + 1 vib nas this = 5 vib nas this.
Qhov nruab nrab ntawm qhov ceev = tag nrho qhov deb / tag nrho lub sijhawm = 150 meters / 5 vib nas this = 30 meters/ib pliag.
Qhov nruab nrab ntawm qhov ceev = kev hloov chaw / lub sijhawm = 50 meters / 5 vib nas this = 10 meters / vib nas this.
2. Ib tug tub ntxhais kawm taug kev 4 meters mus rau sab hnub tuaj hauv 1 vib nas this thiab tom qab ntawd tig mus rau sab qaum teb rau 3 meters hauv 1 vib nas this. Txheeb xyuas qhov ceev nruab nrab thiab qhov loj ntawm qhov ceev nruab nrab.
Kev Sib Tham
Qhov kev taw qhia ntawm kev txav mus los yog sab qaum teb sab hnub tuaj (kev taw qhia ntawm tus xub txiv kab ntxwv).
Tag nrho lub sijhawm = 1 vib nas this + 1 vib nas this = 2 vib nas this.
Qhov nruab nrab ntawm qhov ceev = tag nrho qhov deb / tag nrho lub sijhawm = 7 meters / 2 vib nas this = 3,5 meters / vib nas this
Qhov nruab nrab ntawm qhov ceev = kev hloov chaw / tag nrho lub sijhawm = 5 meters / 2 vib nas this = 2,5 meters / vib nas this
3. Saib daim duab hauv qab no! Ib tug neeg tab tom ncig ib daim teb plaub fab. Ntev = 50 meters, dav = 20 meters. Tom qab ncig daim teb ob zaug, tus neeg ntawd rov qab mus rau qhov chaw pib. Yog tias lub sijhawm = 100 vib nas this, txiav txim siab qhov nruab nrab ntawm qhov ceev thiab qhov loj ntawm qhov nruab nrab ntawm qhov ceev.
Kev Sib Tham
Qhov ncig ntawm daim teb = 2 (50 meters) + 2 (20 meters) = 100 meters + 40 meters = 140 meters.
Lub teb raug puag ncig 2 zaug = 2(140 meters) = 280 meters.
Qhov Nrug = 280 meters.
Tom qab mus ncig teb chaws tas, tus neeg ntawd rov qab mus rau nws qhov chaw qub vim yog qhov ntawd. kev hloov pauv = 0 meters.
Qhov nruab nrab ntawm qhov ceev = qhov deb / lub sijhawm = 280 meters / 100 vib nas this = 2,8 meters / vib nas this.
Qhov nruab nrab ntawm qhov ceev = kev hloov chaw / lub sijhawm = 0 / 100 vib nas this = 0.
4. Lub rooj hauv qab no muab cov ntaub ntawv hais txog kev mus ncig ntawm ib yam khoom los ntawm qhov chaw A mus rau F raws txoj kab X nrog rau lub sijhawm kaw cia.
Qhov nruab nrab ntawm qhov ceev ntawm cov khoom los ntawm A mus rau D yog ...
A. -2,47m/s
B. -1,00 m/s
C. 1,00 m/s
D. 1,23 m/s
E. 2,47 m/s
Kev Sib Tham
Qhov Nrug AB = 52-30 = 22 meters
Qhov Nrug BC = 52-38 = 14 meters
Qhov Nrug CD = 38-0 = 38 meters
Tag nrho qhov deb = 22 + 14 + 38 = 74 meters
Tag nrho lub sijhawm sib nrug = 30 vib nas this
Qhov nruab nrab ceev = 74 meters / 30 vib nas this = 2,47 m/s
Cov lus teb yog yog E.
Cov lus nug txog qhov nruab nrab ntawm qhov ceev thiab qhov nruab nrab ntawm qhov ceev
1. Ib lub tsheb khiav ncaj nraim mus rau sab hnub tuaj li 80 meters hauv 10 vib nas this thiab tom qab ntawd khiav ncaj nraim mus rau sab hnub poob li 60 meters hauv 10 vib nas this. Txheeb xyuas seb qhov ceev nruab nrab dan qhov ceev nruab nrab txawb tau.
2. Ib tug tub ntxhais kawm taug kev 8 meters mus rau sab hnub tuaj hauv 2 vib nas this thiab tom qab ntawd tig mus rau sab qaum teb rau 6 meters hauv 2 vib nas this. Txheeb xyuas qhov ceev nruab nrab thiab qhov loj ntawm qhov ceev nruab nrab.
3. Saib daim duab hauv qab no! Ib tug neeg tab tom ncig ib daim teb plaub fab. Ntev = 100 meters, dav = 50 meters. Tom qab ncig daim teb peb zaug, tus neeg ntawd rov qab mus rau qhov chaw pib. Yog tias lub sijhawm = 100 vib nas this, txiav txim siab qhov ceev nruab nrab thiab qhov loj ntawm qhov ceev nruab nrab.
[Lus Askiv: Qhov nruab nrab ntawm qhov ceev thiab qhov nruab nrab ntawm qhov ceev - teeb meem thiab kev daws teeb meem ]
