7 mau laʻana o nā nīnau hoʻolalelale centripetal
1. Ua nakinaki ʻia kahi pōhaku i ke kaula a laila hoʻohuli ʻia a hiki i ka wā e hoʻohuli ai ka pōhaku i kahi kihi o 360°.o i kēlā me kēia 1 kekona. Inā he 20 kenimika ka lōʻihi o ke kaula, e hoʻoholo i ka nui o ka wikiwiki centripetal o ka mea!
Pahana
Ua ʻike ʻia :
Ka wikiwiki kihi (ω) = 360o/kekona = 1 hoʻohuli / kekona = 6,28 radians/kekona
ʻO ka lōʻihi o ke kaula = radius (r) o ke ala pōʻai = 20 cm = 0,2 mika
Ua nīnau ʻia : ka wikiwiki ʻana o ke kikowaena (as)
Pane :
2. Ke wili nei kahi huila me ka radius o 30 cm i ka wikiwiki angular o 180 rpm. E hoʻoholo i ka wikiwiki centripetal o kahi kiko ma ka lihi o ka huila!
Pahana
Ua ʻike ʻia :
ʻO ke kaʻina (r) o ka huila = 30 kenimika = 0,3 mika
Ka wikiwiki angular (ω) = 180 mau hoʻololi / 60 kekona = 3 mau hoʻololi / kekona = (3)(6,28 radians) / kekona = 18,84 radians/kekona
Ua nīnau ʻia : ka wikiwiki ʻana o ke kikowaena (as) ma r = 0,3 mika
Pane :
3. Hoʻokele kekahi mea hoʻokūkū i kahi kaʻa a puni kahi piʻo hapa pōʻai me ka radius o ke kūlou ʻana o 50 mika. Inā he 72 km/hola ka wikiwiki o ke kaʻa, he aha ka wikiwiki centripetal o ke kaʻa?
Pahana
Ua ʻike ʻia :
Radius (r) = 50 mika
Ka wikiwiki (v) = 72 km/hola = (72)(1000 mika) / 3600 kekona = 20 mika/kekona
Ua nīnau ʻia : ka nui o ka wikiwiki centripetal (a)s)
Pane :
ʻO ka nui o ka wikiwiki centripetal o ke kaʻa:
as = v2 / r = 202 / 50 = 400 / 50 = 8 m/s2
4. Ke holo nei kekahi kaʻa ma kahi piʻo me ka wikiwiki radial o 10 m/s2, kahi i loaʻa ai kēia ka wikiwiki centripetal kiʻekiʻe loa e hiki ai i ke kaʻa ke hoʻokō me ka ʻole o ka heʻe ʻana mai ke ala. Inā he 108 km/h ka wikiwiki o ke kaʻa, he aha ka radius o ke kūlou o ka piʻo i ʻole e heʻe ke kaʻa?
Pahana
Ua ʻike ʻia :
Hoʻolalelale kikowaena (a)s) = 10 m/s2
Ka wikiwiki o ke kaʻa (v) = 108 km/hola = (108)(1000) / 3600 = 30 mika/kekona
Ua nīnau ʻia : radius (r)
Pane :
Radius o ke kūlou ʻana:
r= v2 / hes
r = 302 / 10 = 900 / 10 = 90 mika
5. Nā Nīnau Hoʻokolohua Lahui 2003/2004
He kiʻikuhi e hōʻike ana i ka pilina ma waena o ka wikiwiki centripetal (a s ) a me ka wikiwiki linear (v) i ka neʻe pōʻai like ...
Pahana
ʻO ke ʻano hoʻolalelale centripetal:
Wehewehena: a s = ka wikiwiki centripetal, v = ka wikiwiki linear, r = ka mamao mai ke axis o ka wili.
Ke noiʻi nei mākou i ka pilina ma waena o ka wikiwiki centripetal (a s ) a me ka wikiwiki linear (v) i mea e mau ai ka mamao mai ke axis o ka wili (r). Manaʻo ʻia ʻo r = 1.
Piʻi linear ka waiwai o v, piʻi exponential ka waiwai o as.
ʻO A ka pane pololei.
6. Nā Nīnau Hoʻokolohua Lahui no SMA/MA Physics U-ZC-2013/2014 Helu 4
Ua milo ʻia ke kinikini i loko o kahi pola poepoe me ke anawaena o 1 m. Inā e milo ke kinikini a puni ka lihi o ke pola ma ka wikiwiki angular mau o 50 rpm, a laila ʻo ka wikiwiki linear a me ka wikiwiki centripetal o ke kinikini he….
A. 50 ms -1 a me 2500 ms -2
B. 5π ms -1 a me 25π 2 ms -2
C. 5π/3 ms -1 a me 25π 2 /18 ms -2
D. 5π/6 ms -1 a me 25π 2 /18 ms -2
E. 5π/12 ms -1 a me 25π 2 /36 ms -2
Pahana
Ua ʻike ʻia:
Anawaena pōʻai (D) = 1 mika
Ka laulā o ka pōʻai (r) = 0,5 mika
Ka wikiwiki kihi (ω) = 50 rpm = 50 mau hoʻololi / 1 minuke
1 kipi = 2π radians
50 mau kipi = 50 (2π radians) = 100π radians
1 minuke = 60 kekona
Ka wikiwiki angular (ω) = 100π radians / 60 kekona = (10π/6) radians/kekona
Nīnau: Ka wikiwiki laina (v) a me ka wikiwiki centripetal (a s )
Pane:
Ka wikiwiki laina (v):
v = r ω = (0,5)(10π/6) = 5π/6 m/s
Hoʻolalelale kikowaena (a)s):
a s = v 2 /r = (5π/6) 2 : 0,5 = 25π 2/36 : 0,5 = (25π 2/36 )(1/ 0,5)
he s = (25π 2 /18) m/s 2
ʻO D ka pane pololei.
7. Nā Nīnau Hoʻokolohua Lahui 2007/2008 P4 Helu 6
Neʻe kahi mea i ka wikiwiki mau v ma ke ala pōʻai me ka radius R me ka wikiwiki centripetal (a s ). I mea e pālua ai ka wikiwiki centripetal i ka mua, a laila...
Hana ʻia ʻo A. v i 4 mau manawa a hana hou ʻia ʻo R i 2 mau manawa
ʻO B. hana ʻia ʻo v i ʻelua manawa a hana hou ʻia ʻo R i ʻehā manawa
Hana ʻia ʻo C. v i ʻelua manawa a hana hou ʻia ʻo R i ʻelua manawa
Noho ʻo D. v a ua pāpālua hou ʻia ʻo R
Ua pāpālua hou ʻia ʻo E. v a noho mau ʻo R
Pahana
