ĐỀ VÀ ĐÁP ÁN HSG VẬT LÍ 12 QUẢNG TRỊ 2014-2015

SỞ GIÁO DỤC VÀ ĐÀO TẠO
QUẢNG TRỊ
KÌ THI CHỌN HỌC SINH GIỎI VĂN HÓA 12 THPT
Khóa ngày 05 tháng 03 năm 2015
 VẬT LÍ
180 

Câu 1. 
 !"#$%&'()*+,-!"#$.!,/0
)"!1#2 )32'-
+

,-


)456!7)8,9:
a)(68!"#$; ,<
562=
+

,-


:
b) #(>5?@= +
"'/'-
( )
A
:+
&
−

π
(?BCD6
#(>5?@= 2"'/
( )
A
E:+
&
−
π
:
Câu 2.E
"D4!FG-HIJ!-
' +=
K6JBLM:&I!"6-N6
O6,M(F5P,/KDLQRS)3,6,/D4!FG8>!FGD
!$TM:&I'-"D5>"="5@D'-UVQ:J<L"6G
D>D4!FG'-+WD:XY,-Z>D4!FG5>"D'K')4'-Q
E

,-Q:8?0KC[,-ZD4!FG* 0!6;\:
Câu 3.E
1."]D<-(#5)/D0D05P)30
S^_F:`<O6??0[S
( )
 + E = ±
?0$
S<-
( )
a +A Q = ±
,-""=+?,F'-

( )
% b +A = ±
:cG
(DDLdL=Y:
2.(#^_F,0D0Se)4<60D0B
5)/D$+Q<fAZ'-">- 552N
,FD0,-"552N '-52N -6,-5)/DQb:cG(5g
,FD0=0D0,- Z:
Câu 4.(5,0 điểm)
1. h#0NG6
( )

6 i D + = π + ϕ
,-K6UJ=  BL
<H#*6Kj@##!6&,-6"?6K".?%GT
)4:6d".?=6"!FG0M'K')4'-%
+
V+Wπ%

VEWπ8
56  2  )  "  !1  #  2       'K  ')4  '- 
( )
+
   D +  U
A
π
 
= π +
 ÷
 


( )

   D +  U
E
π
 
= π −
 ÷
 
:(0Mj,-#!6&=@#:
2.& #UJH"#*6Kj@#&,-"6"!FGBL<
S2.:k]'-L[j,-&ZL[&,-6"!FG:h,-K6
  UJ#0NG6
( ) ( )
6 + A D +  l= π
 8)4#0#6!@
J
i +l=
#06
UZ
'#πWD,/6
J
H6
UJ
'#πWED,/6
UZ
:J<
D6C>6@= '-EAm:(D6C>6@= LB
K66"!FG:

+
ĐỀ CHÍNH THỨC
Câu 5. Q
1. 'B'1NL6)4S\2)8,9:J<L')4
+ 
  + = =
"2
+ 
   Z W = =
: ,M(F5P,g
nP>")\P,-06" 
+ 
I I +Q =
:`((H ?,g!"61
S0006$,M(F5P,g
+
)46G,gL
AWD)/\2'>>o

)4?p$"(!)/
,M(F5P0,M(F5P" +Q:&]@]"IN
)/\2N6L!)/LI ,M(F5PL'
0,g5BK6!":
a)l<0)38!"61=,g
+
,-,g

:
b) ,g
+

m
*,M('"
cmx 
+
=
,-?
cG(L"=,g

 
( )
 q  D

π
= +
:
c)(?0'/C[
+
,-

O608!":
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'K')4'-
+
,-

,g
+
,-

L')45P6:JK60'1N5M5<

! ,g<N6,-)4D0!]2UJP:`Y,g

+
'1N
+
5MY' " U
+
H?p:l [,g'-N6G>F-H:
cG("Y'/C='1N

D6, o?6G",-(68
!"=#:
HẾT

I
+
I

m
2
m
1



+
U
J
k
2

k
1