|
|
?????????????
????????????????????????
????
?2014??????R?????????O?????????A??????????O???????????????????v????????OA?????v??????????????????????????A???????g ????????
O???h ?_________??????????? ?_________?
?2008?????????????????????M????r1????N????r2???????????????????n?????????????????????????BC? A?????????? B?????????? C???????? r1 n/ r2 D????????r2n/ r1
?2009???????????????a?b?c
???????
??????????????????????????????????B?
A?a?b?c?????????? B?a?b?c???????? C?a?b?????c?? D?c?????a?b??
(2010???1)??????????????????????????????????????????????????????????????????????????????????????????????????????????????????? (1)?????????????????5???????????? 4.55 ?r/s????3?????? ?2????????????3??????
?????????????????( 1.46 )
?
??????
?2009????????????????????????????????????????????????????????????????????????????????????????????t??????????N????????????? = ____??????????????????????r1????????????_________????????????????????????????????v
=_______???????????
?=2? ??????r2?????????R?2???v?2? R
?????
?
2011?????????????????????????????????????????????????????????????a ????????A ???????????
A ???????A ???????????????????????A ????????????A ???????????????????????????0??????b ????????????p ????????C?
A. B. C. D.
?2005???????????????????????????????( C ) A.?????????? B.?????????? C.?????? D.?????? ???
?2005??????????????????P?????????????????????m?????????????????R????????????????????????????????
.
?2013???????????R???????????????????????????????????O????OO??????????????????????m??????????????????????????????????????O?????OO????????60?????????g?
?1???=?0?????????????????0?
?2??=?1k??0??0?k<< 1?????????????????
????1?
?2??????????????????????
???????????????????
?2012??????????????????????????????????????????????????????????????R=0.5 m,????????H=0.8m,???????????????s=0.4m??????????????????
2
?????????g=10m/s ?? ?1??????????????V0? ?2?????????????????? 1m/s 0.2
?
(2010??)????????????????????????????????m????????????????????????????????????????????????d??????????????????????
d?????????
?d???????g.??????????????
(1)??????????v1??????????v2. (2)?????????????
(3)???????????????????????????????????????????????????????????
??? (1)v1? v2? (2)mg
(3)l?
xm?d
(2013???
2)
??????????????????????????????????????????vc ????????????????????????????AC?
A.????????
B.??????vc??????????
C.??????vc????????????????????????
D.???????????????vc ????
(2013??)???????????????A?
B?????????????????????????????????????????????????????????????D?
A?A????B??
B?A?B??????????
C???A?B????????????? D???A???????????B??
??????????(???)
????
???????????
1?????????????????
(1)???v?????????????????????????v?????????????????????m/s?
?2????????????????????????????????
s2?r
; ?
tT
?
t
?
2?? T
????????????rad?s?
(3???T???????????????????????????s?
?4???f?????????????????????????????????? Hz? ?5???n????????????????????r?s???r?min? 2??????????????????
?????????????????????????????????????v?r??T??
f
v?2?
???2?f?
????????????????????????????????????????????? ??????????? 1????
?1?????????????????????????
?2????????????????????????????????????? 2??????
?1??????????????????????????????
?2????????????????????????????????????
2v224?2 an???r?
Tr
???
1.???V?s/t?2?r/T 2.??????/t?2?/T?2?f 3.?????a?V/r??r?(2?/T)r
4.???F??mV/r?m?r?mr(2?/T)?m?v=F? 5.??????T?1/f
6.???????????V??r
7.???????????2?n(???????????)
8.???????????s:?(m)????????rad????f???Hz????T???s????n?r/s???r???m?????V??m/s????????rad/s?????????m/s??
?????????
2
2
2
2
2
2
2
v2
1???F?m ?r F?m
r
2
v24?22
??r?2r?4?2 f 2r?????a??1????a =rT
?2??????????????
?3??????????????????? ??????
???????????
v2
?????? ??????m
r
? ????? ????
? ???? ?0 ????
1?????
????????????????????????????
v2
?v?grtan?,v??????????v??????? mgtan??mr
??????????????
2??????
N
v2
mgcos??N?m
r
? = f
?????????
mg
v2
mg?N?m ????????mg?N
r
???F?mv / r????????????F?v???????F
?v???????
3?????
2
Nsin??mg
Ncos??m?2r?tan??
g
?2r
???
grtan?
????????R?????????????????????????????????????????????????v???T????
mv2
mgtan???mRsin??2?
Rsin?
?????v?
gRtan?sin?,T?2?
Rcos?h?
?2?gg
4????
N ?
F
??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????
mv2
?mg ????????????????????F?mg?R
?v?gR???????????
mv2
?mg,?v?gR?????????????????????????????mg?F?R
?????????
???????????????????????????????????????v??????????????????v????????v?
gR????????????????v?gR?????????
gR???????????????????F<mg?????????mgF??
????F>mg??????????F +mg????F=mg????????? ????????????????????????????
v24?22
?m?R?m2R?m4?2f2R 1???? ?1????F?ma??mRT
?2??????????????
2??????
??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????
?????????????????????????????????Fn=man???????????????????????????????????????????????????mv2?2??? ?m?2R?m??R??????RT??
2
??1? ???????????????????????????????????????????????h?A???????????ABC?????????????????????????????3?4??????R????????sBC=2R???????????????????h??????
????????
??2?????????????????M=0.6kg???A?????????????????????????O?????m=0.3kg???B?A????O?????0.2m??A????????????f=2N?????B???????????O?????????????
??3??????????????????????????R???????????????????????????????????????A?????m1?B?????m2?????????????????????????v0??A?????????B?????????????????????????????m1?m2?R?v0????????______?
??5???????????????????????A???????B??????????????????????????????????C????????????????????A??????AB??????????.
???????????????????????????????????????????????????????????????????R????????????????????????L????????????????h???????????????????????????????????????????????????(????????????????????????????g)???
(1)???????????????H? (2)?????????.
??????????(???)
??????
???????????
1?????????????????
(1)???v?????????????????????????
s2?rv??;
tT
????????????????????m/s?
?2??????????????????????????????
?2?????
tT
????????????rad?s?
(3???T???????????????????????????s? ?4???f?????????????????????????????????? Hz? ?5???n????????????????????r?s???r?min? 2??????????????????
?????????????????????????????????????v?r??T??v?2????2?f?
f
?????????????????????????????????
???????????? ??????????? 1????
?1?????????????????????????
?2?????????????????????????????????????
2??????
?1??????????????????????????????
?2????????????????????????????????????
2v224?2 an???r?
r
???
1.???V?s/t?2?r/T
2.??????/t?2?/T?2?f
3.?????a?V2/r??2r?(2?/T)2r
4.???F??mV2/r?m?2r?mr(2?/T)2?m?v=F? 5.??????T?1/f
6.???????????V??r
7.???????????2?n(???????????) 8.???????????s:?(m)????????rad????f???Hz????T???s????n?r/s???r???m?????V??m/s???????
?rad/s?????????m/s2??
?????????
v2
1???F?m ?r F?m
r
2
v24?22
??r?2r?4?2 f 2r ?2??????????a??1????a =rT
????????? ?3??????????????????? ??????
???????????
v2
?????? ??????m
r ? ????? ????
? ???? ?0 ????
1?????
????????????????????????????
v2
mgtan??m?v?grtan?,v??????????v??????
r?
??????????????
2??????
mgcos??N?m mg sin? = f
?????????
v
r
2
v2
mg?N?m ????????mg?N
r
???F?mv2 / r????????????FF?
v???????
v2
?? ?N?mg?m (????)
r
3?????
Nsin??mg
????????R?????????????????????????????????????????????????v???T????
mv2
mgtan???mRsin??2?
Rsin?
Ncos??m?r?tan??
2
g
?r
2
???
g rtan?
?????v?gRtan?sin?,T?2?Rcos??2?h?
g
g
4????
??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????
mv2
?mg ????????????????????F?mg?R?v?gR???????????
??????????????????????
mv2
mg?F??mg,?v?gR????????????????
R
???????????????????????????????????????v??????????????????v?gR????????????????v?gR????????????????v?gR???????????????????F<mg?????????mgF??????F>mg??????????F +
mg????F=mg????????? ????????????????????????????
v24?22
1???? ?1????F?ma??m?m?R?m2R?m4?2f2R
RT?2??????????????
2?????? ??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????
?????????????????????????????????Fn=man????????????????????????????????
2
2?????????????????????mv?m?2R?m?? ??R??????
R?T?
2
??1? ????????????????????????
???????????????????????h?A???????????ABC?????????????????????????????3?4??????R????????sBC=2R???????????????????h??????
???????????????????????????
??F????????F?1.25mg???????????37o???6???????????????????????D????????D?????D?????????????
22vDvD
?????????F?m ??1.25mg?m
RR
312
??????mg(h?R?Rcos37?)?mg?(hcot??2R?Rsin37?)?mvD
42
?????????????h?
????????
??2?????????????????M=0.6kg???A?????????????????????????O?????m=0.3kg???B?A????O?????0.2m??A????????????f=2N?????B???????????O?????????????
?????B???A?????????????????????A???????????????????????????A??????????????O??????????A?????????????????O?
2
??B?T=mg ??A?T?f?Mr?12 T?f?Mr?2
?1?6.5rad/s?2?2.9rad/s ?? 2.9 rad/s ?
??6.5rad/s
??3??????????????????????????R???????????????????????????????????????A?????m1?B?????m2?????????????????????????v0??A?????????B?????????????????????????????m1?m2?R?v0????????______?
???A?????????????????????????????????????????????????????B?????????????????????B?????????????
112
????m2v2?m2g?2R?m2v0
22
????????
2
v2v0
??A??N1?m1g?m1??B??N2?m2g?m2
RR2
v0
? N1=N2?? (m1?m2)?(m1?5m2)g?0
R
??5???????????????????????A???????B??????????????????????????????????C????????????????????A??????AB??????????.
v
??????????R???C??mg=mC?
R
2
??C???????????2R?gt2?2 ? vCt?sAB? ?B?C??? mvC2/2+2mgR?mvB2/2 ? ?A?B?????vB2?2asAB? ???????????? a=5g?4
?6??????M??????????????????????L????m????????V0??????????????????????????????????????V0????????????? ?1??????????????????????(m?M)g?(m?M)V22/L
11
?????????(m?M)V22?(m?M)V12?2(m?M)gL
22
????????V0?
m?
M
m
gL.
(2)???????????????????????L????
???????????????????
?????http://www.850500.com/news/18248.html
?????,??! |
|