SỞ GIÁO DỤC VÀ ĐÀO TẠO
QUẢNG TRỊ
KÌ THI CHỌN HỌC SINH GIỎI VĂN HÓA 12 THPT
Khóa ngày 05 tháng 03 năm 2014
 VẬT LÍ
180 
(Đề thi có 02 trang, gồm 05 câu)
Câu 1. (4 điểm)
 !"#$%&'!()*+
, /012 3 
% '
  4"56 7
= = π
 89+"
:7;<!1=>?&@1+A12-BC%'&
D1=9EFG"H%I'JK&L31=9EM4F
NG"H%NI'NJ(O&L7
a)A1EHD"&9#1=9EPB?DB7
b)QRSPHT012FC%'7A"HB?&B
?S7
c)UP*+129+B?+-V=%&
9!A%'7AW!XYU#-/%'7
Câu 2.(4 điểm)
?*+Z8A-[BG*+GYB*1237?
P*VG?-+\π%1P]&"W
^53GA9W_+247(6
`a
87
a)A3*+GY?7
b) bP&KLc]-$:+
?*+Z8-$*BdY-C+

b
G+
4
O
π
7
a)Ao&&Z&81Pl7
b)8G*8D:#!p8
(
"Hm
C1#
O
b
PB?7
`eiDT!p"HmC1#b
O
7
`b#90CGG#0kb
4
7
Câu 4. (4 điểm)
+VTG"HP J(66U^&H-$!@&
+k-$dHp&kV?-$X12H-$
(
J6&Le3
O78
(
-$X120H-$
4
J6&L78!

H-$
4
J(&6D+, @121E
H1
6
J(6^"21?TD=12FWk(7w1?&FW
k49E-$?1P?!-/0Fq+
?4&VFWk(D+7x*=D,$12
 /0
θ
J(46
6
3*=D+!?qS!
q+WTe357w&FWk(FDFqS
//07
a)A1EHCFWk
4
D"1?7
b)jFWk(BG-$D+V3W!HTW
9@9fZDJ(6^"
4
7'F"0WC-7
HẾT
• Thí sinh không được sử dụng tài liệu.
• Giám thị không giải thích gì thêm.
4^4
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HƯỚNG DẪN CHẤM
ĐỀ THI CHỌN HSG VĂN HÓA 12 THPT

k
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= =
+
7
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4
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YW 1,.&
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ω = = =
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6 6
 6nT 4n1 6
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% " 6 % 4
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⇒ ⇒
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− ω ϕ = =
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( ) ( )
T 4 " (6 
= + π
6&L
6&L
b)
8RGFD#X12
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4
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(
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4
F 4
•  €  € ( €  T € (
= = ⇒ ω =
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4 4
4
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€ T € 6&64 4
 6&L7(6
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ω
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4
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6&4L
6&4L
bED
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4
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( )
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4
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&
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1  % " (6 4 z 6
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(
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
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o
= ⇒ =
4
D41P(
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(
1 OZ O) O6
o 6&O 
4 46
− −
= = =

6&4L
6&L
bEDFWk(D+V12W!
( )
T Z o 6&K ≥ − =
7
6&L
Ghi chú: Thí sinh có thể giải cách khác nếu đáp số đúng thì cho điểm tối đa, sai phần nào
thì trừ điểm ngang phần đó.
Hết
)^4