4 Piv txwv ntawm Cov Lus Nug Txog Lub Zog Centripetal
1. Ib yam khoom uas muaj qhov hnyav li 200 grams raug khi rau ntawm txoj hlua sib dua thiab tom qab ntawd tig kab rov tav nrog qhov ceev ntawm lub kaum sab xis tseem nyob ntawm 5 rad s-1, zoo li nyob rau hauv daim duab hauv qab no. Yog tias qhov ntev ntawm txoj hlua yog l = 60 cm, ces qhov loj ntawm lub zog centripetal ua rau ntawm qhov khoom yog...
A. 0,3 N
B. 0,6 N
C. 3 N
D. 6 N
Sab Hnub Tuaj 30 N
Kev Sib Tham
Nws paub tias:
Qhov hnyav ntawm yam khoom (m) = 200 grams = 200/1000 kg = 2/10 kg = 0,2 kg
Lub zog ntawm lub kaum sab xis (ω) = 5 radians/ob vib nas this
Qhov ntev ntawm txoj hlua = lub vojvoog (r) ntawm txoj kev vojvoog = 60 cm = 60/100 meters = 0,6 meters
Nug: Qhov loj ntawm lub zog centripetal uas ua rau ib yam khoom yog ....
Lus teb:
Lub zog centripetal yog lub zog tshwm sim uas ua rau ib yam khoom muaj kev nrawm centripetal. Cov mis rau lub zog centripetal yog:
∑F = mas
∑F = mv2/r = m ω2 r
Cov Ntaub Ntawv: ∑F = lub zog centripetal, m = qhov hnyav ntawm yam khoom, v = qhov ceev tangential, ω = qhov ceev ntawm lub kaum sab xis, r = radius ntawm txoj kev vojvoog.
∑F = m ω2 r = (0,2)(5)2 (0,6) = (0,2)(25)(0,6) = 3 Newtons
Cov lus teb yog C.
2. Ib tug tub ntxhais kawm tig ib lub pob zeb khi rau ntawm qhov kawg ntawm ib txoj hlua. Lub pob zeb tig kab rov tav raws li qhia saum toj no. Yog tias qhov ceev ntawm kev tig ntawm lub pob zeb yog ob npaug, lub zog centripetal yuav dhau los ua...
A. 6 zaug thawj
B. 5 zaug dua
C. 4 zaug ntxiv
D. 2 zaug dua
E. 2 zaug thawj
Kev Sib Tham
Nws paub tias:
Qhov hnyav ntawm pob zeb = m
Qhov ceev ntawm pob zeb = v
Qhov ntev ntawm txoj hlua = radius = r
Nug: Yog tias qhov ceev nce ob npaug, lub zog centripetal yuav dhau los ua ...
Lus teb:
Yog tias qhov ceev yog ob npaug, ces lub zog centripetal dhau los ua:
Lub zog centripetal dhau los ua 4 npaug ntawm thawj.
Cov lus teb yog C.
3. Ib txoj kab nkhaus ntawm txoj kev tiaj tiaj yog tsim los rau lub tsheb kom khiav tau qhov ceev tshaj plaws ntawm 10 m/s.-1. Paub tias tus coefficient ntawm kev sib txhuam ntawm lub log tsheb thiab txoj kev yog 0,5 thiab lub vojvoog ntawm kev nkhaus ntawm txoj kev yog R m. Ces tus nqi ntawm R yog .... (g = 10 ms-2)
A. 7,5 meters
B. 8,0 meters
C. 10 meters
D. 15 meters
E. 20 meters
Kev Sib Tham
Nws paub tias:
Ceev (v) = 10 m/s
Tus coefficient ntawm kev sib txhuam ntawm lub log tsheb thiab txoj kev (μs= 0,5 TZS
Kev nrawm vim lub ntiajteb txawj nqus (g) = 10 m/s2
Nug: Lub vojvoog ntawm qhov nkhaus ntawm txoj kev (R meters)
Lus teb:
Lub zog tsuas yog tshwm sim hauv kev taw qhia kab rov tav uas ua rau lub tsheb thaum lub tsheb tig yog lub zog sib txhuam zoo li qubCov mis ntawm kev sib txhuam zoo li qub:
4. Lub tsheb tab tom tsav ntawm txoj kev nkhaus ntawm qhov chaw M raws li pom hauv daim duab hauv qab no.
Tus coefficient ntawm static friction ntawm lub log thiab txoj kev yog 0,4 (gravitational acceleration 10 ms-2). Yuav kom lub tsheb tsis txhob tawm ntawm txoj kev, qhov ceev tshaj plaws uas tso cai yog...
A. √10 ms-1
B. 2√10 ms-1
C. 4√10 ms-1
D. 5√10 ms-1
E. 6√10 ms-1
Kev Sib Tham
Nws paub tias:
Cov coefficient ntawm kev sib txhuam zoo li qub (μ)s= 0,4 TZS
Kev nrawm vim lub ntiajteb txawj nqus (g) = 10 m/s2
Lub vojvoog ntawm qhov nkhaus (R) = 40 meters
Nug: qhov ceev tshaj plaws (v)
Lus teb:
Cov mis Txoj cai thib ob ntawm Newton rau lo kev txav mus los ib puag ncig
Cov Ntaub Ntawv:
ΣF = lub zog centripetal = lub zog tshwm sim = tag nrho lub zog, m = qhov hnyav ntawm yam khoom, as = kev nrawm ntawm lub centripetal, v = linear velocity, R = radius of curvature
Lub zog centripetal
Lub zog centripetal yog lub zog uas tig mus rau hauv nruab nrab ntawm txoj kev voj voog. Thaum lub tsheb txav mus rau hauv lub voj voog, tsuas muaj lub zog tig mus rau hauv nruab nrab xwb yog kev sib txhuam zoo li qub, yog li kev sib txhuam zoo li qub yog lub zog centripetal.
Cov qauv sib txhuam static:
Cov Ntaub Ntawv:
μs = coefficient ntawm kev sib txhuam static, w = qhov hnyav ntawm yam khoom, m = pawg ntawm yam khoom, g = kev nrawm vim yog lub ntiajteb txawj nqus.
Xam qhov ceev tshaj plaws (v):
Cov lus teb yog C.
Qhov chaw nug lus:
Cov Lus Nug Txog Kev Xeem Physics Hauv Tebchaws Rau Tsev Kawm Ntawv Theem Siab/Tsev Kawm Ntawv Theem Siab Ua Haujlwm
