7 piv txwv ntawm kev hloov pauv ib puag ncig
1. Ib lub kiv cua uas thaum xub thawj so, tig nrog lub kaum sab xis tas li ntawm 2 rad/s.2. Txheeb xyuas qhov kev nrawm ntawm lub kaum sab xis thiab qhov ceev ntawm lub kiv cua 2 vib nas this tom qab. Qhia lawv hauv radians thiab vib nas this.
Kev Sib Tham
Nws yog paub :
Nug : kev nrawm ntawm lub kaum sab xis thiab qhov nrawm ntawm lub kaum sab xis tom qab 2 vib nas this
Jawb :
(A) Kev nrawm nrawm tom qab 2 vib nas this
Qhov kev nrawm ntawm lub kaum sab xis yog qhov tsis hloov pauv yog li ntawd tom qab 2 vib nas this, qhov kev nrawm ntawm lub kaum sab xis tseem yog 2 rad/s2.
(B) Qhov ceev ntawm lub kaum sab xis tom qab 2 vib nas this
Kev nrawm ntawm lub kaum sab xis 2 rad/s2 = 2 radians/ob vib nas this ib ob txhais tau tias qhov ceev ntawm lub kaum sab xis nce ntxiv 2 radians/ob vib nas this txhua 1 vib nas this. Tom qab 1 vib nas this, qhov ceev ntawm lub kaum sab xis yuav dhau los ua 2 radians/ob vib nas this. Tom qab 2 vib nas this, qhov ceev ntawm lub kaum sab xis yuav dhau los ua 4 radians/ob vib nas this.
2. Lub log uas thaum xub thawj so, nws yuav nrawm nrawm ib yam nkaus. Tom qab 10 vib nas this, lub log yuav tig ntawm qhov ceev ntawm 60 rpm. Txheeb xyuas qhov nrawm ntawm lub log!
Kev Sib Tham
Jawb :
Cov mis rau kev txav mus los uas nrawm sib npaug (GMBB) zoo ib yam li cov mis rau kev txav mus los uas nrawm sib npaug (GLBB).
Lub angular acceleration ntawm lub log yog 0,628 rad/ s2
3. Lub zog ntawm lub tog raj kheej hloov pauv sib npaug ntawm 20 rad/s mus rau 10 rad/s hauv 4 vib nas this. Txheeb xyuas qhov kev nrawm ntawm lub tog raj kheej!
Kev Sib Tham
Jawb :
Lub angular acceleration ntawm lub tog raj kheej yog -2,5 rad/s2. Lub cim tsis zoo = qhov kev nrawm lossis kev qeeb qeeb tsis zoo. Yog tias thaum lub sijhawm nrawm, qhov ceev ntawm lub kaum sab xis nce ntxiv, ces thaum lub sijhawm qeeb, qhov ceev ntawm lub kaum sab xis txo qis.
4. Ib yam khoom uas tig thaum xub thawj nrog lub kaum sab xis ceev ntawm 10 rad/s yuav muaj lub kaum sab xis nrawm ntawm 2 rad/s tas li.2Txheeb xyuas lub kaum sab xis uas nyob ib puag ncig yam khoom tom qab 2 vib nas this!
Kev Sib Tham
5. Lub log tsheb uas thaum xub pib tig ntawm qhov ceev ntawm 20 rad/s ces nws yuav tsum tsis tig tom qab nws mus ncig lub kaum ntawm 20 radians. Qhov kev nrawm ntawm lub kaum ntawm lub log yog...
Kev Sib Tham
Jawb :
Lo lus nug no raug daws los ntawm kev siv formula 3.
6. Cov Lus Nug Xeem Thoob Tebchaws Xyoo 1999/2000 P4 No. 26
Ib tug pas nrig PQ ntev 60 cm raug tig nrog lub taub hau Q ua lub axis thiab PQ ua lub vojvoog ntawm kev tig. Tus pas nrig PQ tig los ntawm so nrog lub kaum sab xis ntawm 0,3 rad s -2 . Yog tias qhov chaw pib ntawm lub kaum sab xis = 0, ces qhov ceev linear (v) ntawm lub taub hau P ntawm t = 10 vib nas this yog...
A. 1,8 ms -1
B. 3 ms -1
C. 5 ms -1
D. 30 ms -1
E. 180 ms -1
Kev Sib Tham
Nws paub tias:
Qhov ntev ntawm tus pas PQ = lub vojvoog ntawm lub vojvoog (r) = 60 cm = 60/100 m = 0,60 meters
Qhov ceev pib ntawm lub kaum sab xis (ωo ) = 0 rad/s
Kev nrawm ntawm lub kaum sab xis (α) = 0,3 rad s -2
Initial angular position (θ o ) = 0
Lo lus nug: linear velocity (v) ntawm qhov kawg P ntawm lub sijhawm t = 10 vib nas this
Lus teb:
Ua ntej, xam qhov ceev ntawm lub kaum sab xis ntawm tus pas nrig ntawm lub sijhawm t 10 vib nas this.
Cov mis rau Kev Tawm Tsam Ceev Ceev Sib Xws:
ω t = ω o + α t = 0 rad/s + (0,3 rad s -2 )(10 sec) = 3 rad s -1
Qhov ceev ntawm lub kaum sab xis ntawm t = 10 vib nas this yog 3 radians/ob vib nas this.
Qhov linear velocity ntawm t = 10 vib nas this yog xam siv cov mis rau kev sib raug zoo ntawm linear velocity (v), angular velocity (ω) thiab radius (r).
v = r ω = (0,6 meters)(3 radians/ob) = 1,8 meters/ob.
Cov lus teb yog lawm yog A.
7. Cov Lus Nug Txog Kev Xeem Thoob Tebchaws Xyoo 2002/2003
Ib yam khoom txav mus los hauv ib lub voj voog nrog qhov ceev pib ntawm 4 rad/s thiab muaj kev nrawm ntawm 0,5 rad/s 2 , ces qhov ceev ntawm yam khoom hauv vib thib plaub yog...
A. 4,0 rad/s
B. 4,5 rad/s
C. 5,0 rad/s
D. 6,0 rad/s
E. 8,0 rad/s
Kev Sib Tham
Nws paub tias:
Qhov ceev pib ntawm lub kaum sab xis (ω o ) = 4 radians/ob
Kev nrawm ntawm lub kaum sab xis (α) = 0,5 rad/s 2
Lub sijhawm luv (t) = 4 vib nas this
Lo lus nug: Qhov ceev ntawm cov khoom hauv plaub vib nas this (ω t )
Lus teb:
Cov mis rau kev hloov pauv ntawm kev txav mus los ib puag ncig:
ω t = ω o + α t
ω t = 4 + (0,5)(4)
ω t = 4 + 2
ω t = 6 radians/ob
Cov lus teb yog D.
