Lub zog ntawm qhov sib txhuam static thiab kinetic - teeb meem thiab kev daws teeb meem

Daws cov teeb meem hauv Newton txoj cai ntawm kev txav mus los - Lub zog ntawm qhov static thiab kinetic friction

1. Ib yam khoom nyob rau hauv pem teb kab rov tav. Tus coefficient ntawm static friction yog 0.4 thiab acceleration ntawm gravity yog 9.8 m/s ^2. Txheeb xyuas (a) Lub zog siab tshaj plaws ntawm static friction (b) Lub zog tsawg kawg nkaus ntawm F

tshuaj

Paub:

Qhov hnyav (m) = 1 kg

Tus coefficient ntawm kev sib txhuam zoo li qub (μs ₎ = 0.4

Qhov kev nrawm ntawm lub ntiajteb txawj nqus (g) = 9.8 m/s ²

Qhov hnyav (w) = mg = (1 kg) (10 m/s ² ) = 10 kg m/s ² = 10 Newtons

Lub zog ib txwm (N) = w = 10 Newtons

Xav tau:

(a) Lub zog siab tshaj plaws ntawm kev sib txhuam static (b) Lub zog tsawg kawg nkaus ntawm F

Tshuaj:

(a) Lub zog siab tshaj plaws ntawm kev sib txhuam zoo li qub

f _s = μ _s N

fs = (0.4)(9.8 N) = 3.92 _Newtons

(b) Lub zog tsawg kawg nkaus ntawm F

Yog tias lub zog F siv rau ntawm yam khoom tab sis yam khoom tsis txav mus, yog li ntawd yuav tsum muaj lub zog ntawm kev sib txhuam zoo li qub uas hauv pem teb siv rau ntawm yam khoom. Yog tias yam khoom yuav pib txav mus, lub zog ntawm kev sib txhuam zoo li qub dhau lawm, yuav tsum muaj lub zog ntawm kev sib txhuam kinetic. Yam khoom pib txav mus yog tias F loj dua lub zog siab tshaj plaws ntawm kev sib txhuam zoo li qub.

Yog li ntawd, lub zog tsawg kawg nkaus ntawm F = lub zog siab tshaj plaws ntawm kev sib txhuam zoo li qub = 3.92 Newtons.

[irp]

2. Lub thawv 1 kg raug rub raws ntug kab rov tav los ntawm lub zog F, yog li lub thawv txav mus los ntawm qhov ceev tas li. Yog tias qhov sib txhuam kinetic yog 0.1, txiav txim siab qhov loj ntawm lub zog F! (g = 9.8 m/ ^s2 )

Paub:

_{Tus coefficient ntawm kev sib txhuam kinetic} ( μk ) = 0.1

Lub thawv qhov hnyav (m) = 1 kg

Kev nrawm ntawm lub ntiajteb txawj nqus (g) = 9.8 m/s ²

Qhov hnyav (w) = mg = (1 kg) (9.8 m/s ² ) = 9.8 kg m/s ² = 9.8 Newtons

Lub zog ib txwm (N) = w = 9.8 Newtons

Xav tau : F

Tshuaj:

Txoj cai lij choj thawj zaug ntawm Newton hais tias yog tsis muaj lub zog ua haujlwm rau ib yam khoom, txhua yam khoom yuav txuas ntxiv mus rau hauv nws lub xeev so, lossis qhov ceev tas li hauv ib txoj kab ncaj.

Yog li ntawd, yog tias qhov khoom txav mus rau qhov ceev tas li , yuav tsum tsis muaj lub zog net ( Σ F = 0) . Lub zog F raug siv rau ntawm qhov khoom hauv qhov kev taw qhia kom lub zog ntawm kev sib txhuam kinetic raug siv rau ntawm qhov khoom mus rau sab laug.

∑ F = 0

F – _fk = 0

F = _fk

Lub zog ntawm kev sib txhuam kinetic:

f _k = μ _k N = (0.1)(9.8 N) = 0.98 Newtons

khoom txav nrog qhov ceev tas li, F = f _k = 0.98 Newtons

[irp]

3. Ib yam khoom swb mus rau hauv ib lub dav hlau inclined nrog qhov ceev tas li. Txheeb xyuas qhov sib txhuam kinetic ( _μk ) . g = 9.8 m/s ²

tshuaj

w = qhov hnyav, w _x = feem kab rov tav ntawm qhov hnyav, cov ntsiab lus raws qhov nqes, w _y = feem ntsug ntawm qhov hnyav, perpendicular rau lub dav hlau nqes, N = lub zog ib txwm muaj, f _k = lub zog ntawm kev sib txhuam kinetic.

Paub:

Qhov hnyav (m) = 1 kg

Kev nrawm ntawm lub ntiajteb txawj nqus (g) = 9.8 m/s ²

qhov hnyav (w) = mg = (1 kg)(9.8 m/s2 ⁾ = 9.8 kg m/s2 ⁼ 9.8 Newtons

w _x = w sin 30 ^o = (9.8 N)(0.5) = 4.9 Newtons

w _y = w cos 30 ^o = (9.8 N)(0.5) √ 3 = 4.9 √ 3 Newtons

Lub zog ib txwm (N) = _wy = 4.9 √ 3 Newtons

Xav tau : kinetic friction coefficient ( μk ₎

Tshuaj:

Khoom txav mus rau hauv ib lub dav hlau inclined nrog qhov ceev tas li kom lub zog net = 0.

∑ F = 0

w _x – f _k = 0

w _x = f _k

w _x = μ _k N

5 = μ _k ( 5 √ 3 )

μ _k = 5 / 5 √ 3

μ _k = 1 / √ 3

μk = _0.58

[irp]

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1. Qhov hnyav thiab qhov hnyav
2. ib txwm muaj zog
3. Newton txoj cai thib ob ntawm kev txav mus los
4. Lub zog sib txhuam
5. Kev txav mus los ntawm kab rov tav yam tsis muaj kev sib txhuam
6. Kev txav ntawm ob lub cev nrog tib qhov kev nrawm ntawm qhov chaw ntxhib kab rov tav nrog lub zog sib txhuam
7. Kev txav mus los ntawm lub dav hlau inclined yam tsis muaj kev sib txhuam
8. Kev txav mus los ntawm lub dav hlau inclined nrog lub zog sib txhuam
9. Kev txav mus los hauv lub elevator
10. Kev txav ntawm lub cev txuas nrog cov hlua thiab pulleys
11. Ob lub cev uas muaj tib lub zog ntawm kev nrawm
12. Kev sib hloov ntawm ib txoj kab tiaj tiaj - dynamics ntawm kev txav mus los ncig
13. Kev sib hloov ntawm cov kab nkhaus - dynamics ntawm kev txav mus los ncig
14. Kev txav mus los sib xws hauv lub voj voog kab rov tav
15. Lub zog centripetal hauv kev txav mus los sib npaug