Kev txav mus los nrog kev nrawm tas li - teeb meem thiab kev daws teeb meem

Tau daws cov teeb meem hauv kev txav mus los ncaj - kev nrawm tas li

1. Ib lub tsheb khiav nrawm ntawm qhov chaw so mus txog 20 m/s hauv 10 vib nas this. Txheeb xyuas qhov nrawm ntawm lub tsheb!

tshuaj

Paub:

Qhov ceev pib (v_o) = 0 (so)

Lub sijhawm luv (t) = 10 vib nas this

Qhov ceev kawg (v_t) = 20 m/s

xav : Kev nrawm (a)

Tshuaj:

v_t = v_o + ntawm

20 = 0 + (a)(10)

20 = 10 ib

ib = 20 / 10

ib = 2 m/s²

2. Lub tsheb qeeb qeeb ntawm 30 m/s mus so hauv 10 vib nas this. Txheeb xyuas qhov kev nrawm ntawm lub tsheb.

tshuaj

Paub:

Qhov ceev pib (v_o) = 30 m/s

Qhov ceev kawg (v_t= 0 TZS

Lub sijhawm luv (t) = 10 vib nas this

Xav tau: kev ua kom nrawm (a)

Tshuaj:

v_t = v_o + ntawm

0 = 30 + (a)(10)

– 30 = 10 ib

ib = – 30 / 10

ib = -3 m/s²

Lub cim tsis zoo tshwm sim vim tias qhov kawg tshaj tawm tsawg dua qhov ceev pib.

3. Lub tsheb pib thiab nrawm nrawm nrog qhov ceev tas li 4 m/s² in 1 vib nas this. Txheeb xyuas ceev thiab qhov deb tom qab 10 vib nas this.

tshuaj

(a) Ceev

Kev nrawm 4 m/s² txhais tau tias qhov ceev nce 4 m/s txhua 1 vib nas this. Tom qab 2 vib nas this, lub tsheb qhov ceev yog 8 m/s. Tom qab 10 vib nas this, lub tsheb qhov ceev yog 40 m/s.

(b) Qhov Deb

Paub:

Qhov ceev pib (v_o= 0 TZS

Qhov ceev kawg (v_t) = 40 m/s

Kev nrawm (a) = 4 m/s²

Xav tau: Ze

Tshuaj:

s = v_o t + ½ ntawm² = 0 + ½ (4)(10)²) = (2)(100) = 200 meters

4. Lub tsheb khiav ceev tas li 10 m/s, ces qeeb qeeb li 2 m/s² kom txog thaum so. Txheeb xyuas lub sijhawm dhau los thiab lub tsheb deb ua ntej so.

Paub:

Qhov ceev pib (v_o) = 10 m/s

Kev nrawm (a) = -2 m/s² (Lub cim tsis zoo tshwm sim vim tias qhov ceev kawg tsawg dua qhov ceev pib)

Qhov ceev kawg (v_t) = 0 (so)

Xav tau: Lub sijhawm thiab qhov deb

Tshuaj:

(a) Lub sijhawm luv (t)

v_t = v_o + ntawm

0 = 10 + (-2)(t)

0 = 10 – 2 t

10 = 2 t

t = 10 / 2 = 5 vib nas this

(b) Qhov Deb

v_t² = v_o² + 2 lub qag

0 = 10² + 2(-2) vib nas this

0 = 100 – 4 vib nas this

100 = 4 vib nas this

s = 100 / 4 = 25 meters

5. Lub tsheb khiav ceev 40 m/s, qeeb qeeb li 4 m/s tas li² kom txog thaum so. Txheeb xyuas qhov ceev thiab qhov deb tom qab qeeb qeeb hauv 10 vib nas this!

tshuaj

Paub:

Qhov ceev pib (v_o) = 40 m/s

Kev nrawm (a) = -4 m/s²

Lub sijhawm luv (t) = 10 vib nas this

Xav tau: qhov ceev kawg (v_t) thiab qhov deb (s)

Tshuaj:

(a) Qhov ceev kawg

v_t = v_o + ntawm = 40 + (-4)(10) = 40 – 40 = 0 m/s

0 m/s txhais tau tias lub tsheb so.

(b) Qhov Deb

s = v_o t + ½ ntawm² = (40)(10) + ½ (-4)(10)²) = 400 + (-2)(100) = 400 – 200 = 200 meters

6. Txheeb xyuas qhov deb tom qab 10 vib nas this!

tshuaj

Sab nrauv: s = vt = (10-0)(5-0) = (10)(5) = 50 meters

7. Txheeb xyuas qhov deb tom qab 4 vib nas this!

tshuaj

Qhov nrug = thaj tsam plaub fab + thaj tsam peb ceg

Qhov Nrug = (8-0)(8-0) + ½ (16-8)(8-0) = (8)(8) + ½ (8)(8) = 64 + 32 = 96 meters

8. Txheeb xyuas qhov deb ntawm lub tsheb tom qab 4 vib nas this!

tshuaj

Qhov Nrug Deb = Thaj chaw peb ceg = ½ (4-0)(8-0) = ½ (4)(8) = 16 meters

9. Muaj ib lub tsheb khiav ceev li ntawm 90 km/h dhau ib lub tsheb tub ceev xwm uas nres ntawm ntug kev. Ib feeb tom qab, lub tsheb tub ceev xwm caum at 0.8 m / s²Lub tsheb tub ceev xwm mus txog deb npaum li cases lub tsheb?

Paub:

Qhov ceev ntawm lub tsheb (v) = 90 km/teev = 90,000 meters / 3600 vib nas this = 25 meters/ vib nas this

Lub sijhawm sib nrug (t) = 1 feeb = 60 vib nas this

Kev nrawm ntawm tub ceev xwm lub tsheb (a) = 0.8 m/s²

Qhov ceev pib ntawm tub ceev xwm lub tsheb (v)_o) = 0 m/s

Xav tau: Qhov deb uas lub tsheb tub ceev xwm tau mus

Tshuaj:

Lub tsheb txav mus rau qhov ceev tas li. Qhov deb uas lub tsheb tau mus:

Qhov deb pib:

s = vt = (25)(60) = 1500 meters

Qhov deb kawg:

s = vt = (25)(t)

Tag nrho qhov deb = 1500 + 25 t

Tub ceev xwm lub tsheb txav mus los nrog kev nrawm tas li. Qhov deb uas tub ceev xwm lub tsheb taug kev:

s = v_o t + ½ ntawm² = (0)(t) + ½ (0.8)(t)²) = 0 + 0.4 t² = 0.4 t²

Thaum lub tsheb tub ceev xwm mus txog lub tsheb, qhov deb uas tub ceev xwm lub tsheb mus tau yog tib yam li qhov deb uas lub tsheb mus tau.

Qhov deb ntawm lub tsheb mus ncig = qhov deb uas tub ceev xwm lub tsheb taug kev

1500 + 25 t = 0.4 t²

0.4 t² – 25 t – 1500 = 0

Siv cov qauv quadratic:

Qhov deb uas lub tsheb tub ceev xwm tau mus:

s = 0.4 t² = (0.4)(100²) = (0.4)(10,000) = 4000 meterss = 4 km

10. A tsheb txav mus rau qhov tsis tu ncua 24 m / s brakes kom nws muaj ib qho kev qeeb qeeb tas li ntawm 0.952 m/s². Txheeb xyuas qhov ceev ntawm lub tsheb atom qab qhov deb ntawm 250 meters.

Paub:

Qhov ceev pib (v_o) = 24 m/s

acceleration (a) = – 0.952 m/s² (kos npe tsis zoo vim yog kev qeeb qeeb)

Ze (d) = 250 'meter's

Xav tau: Qhov ceev ntawm lub tsheb tom qab 250 'meter's

Tshuaj:

Paub: qhov ceev pib (v_o), acceleration (ib tug), deb (d), xav tau: qhov ceev kawg (v_t) yog li ntawd siv qhov sib npaug ntawm v_t² = v_o² + 2 ib d

v_t = qhov ceev kawgnyob rau hauv_o = qhov ceev pib, ib = acceleration, d = deb

v_t² = (24)² + (2)(-0.952)(250)

v_t² = 576-476

v_t² = 100

v_t = √100

v_t = 10 m/s

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1. Qhov nrug thiab kev hloov chaw
2. Qhov nruab nrab ntawm qhov ceev thiab qhov nruab nrab ntawm qhov ceev
3. Qhov ceev tas mus li
4. Tsis tu ncua acceleration
5. Kev txav mus los ntawm kev poob dawb
6. Kev txav mus los hauv lub caij nplooj zeeg dawb
7. Kev txav mus rau saum thiab nqis hauv lub caij nplooj zeeg dawb