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ĐỀ THI THỬ ĐẠI HỌC NĂM 2013 SỐ 007 pptx

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ĐỀ THI THỬ ĐẠI HỌC NĂM 2013 SỐ 007

Câu 1: 

-4

A. 3.10
-4
s. B. 9.10
-4
s. C. 6.10
-4
s. D. 2.10
-4
s.
Câu 2: 



  n. 
Câu 3: 


AK


- 4,1V. khi U
AK



A. 1,789.10
6
m/s B. 3,200.10
6
m/s C. 4,125.10
6
m/s D. 2,725.10
6

m/s
Câu 4: 
1


1


2
=f
1


1


A. 2V
1
B. 3V
1
C. 4V

1
D. V
1
Câu 5:  180 V - 



75A và

nào?
A. 

B. 

C. 

D. 


Câu 6:  : 









  =

2

 



 ( ). 



 . Sau khi
, 

. 









 = 4 mH,  = 10
-5
F.

0
/: (



0
 





) :
A. 10 B. 1/10 C. 5 D. 8
Câu 7: 

















 . 


































 
1
t
. 






































2
t
. 
1
t
/
2
t
:
A.1 B. 3/4 C. 4/3 D. 1/2
Câu 8: 





:  



1
= 0,5 

















1
= 4cm. 



i gian t
2
= 12,5 s (








) 








:
A. 160 cm. B. 68cm C. 50 cm. D. 36 cm.
Câu 9: 







, 



 trí cân b




6 cm. 














2T/3 (









 giãn ln
nht ca lò xo trong quá trình vng là :


Trang 2
A. 12 cm. B. 18cm C. 9 cm. D. 24 cm.
Câu 10: 


max

A.40

cm/s B.80 cm/s C.24m/s D.8cm/s
Câu 11: 
 
 

A.1/5. B.1/25. C.7/25. D.1/7.
Câu 12: 
n
= -13,6/n
2




A. 2,4 eV. B. 1,2 eV. C. 10,2 eV. D. 3,2 eV.
Câu 13: goài là

là n
1
và n
2


0


1
, n
2
và n
0
là :
A.
2
0 1 2
.n n n
B.
22
2
12
0
22
12
2.nn
n
nn


C.
22
2
12

2
o
nn
n


D.
2 2 2
0 1 2
n n n

Câu 14: 

AM

BM
-

A.60,23(V) B.90(V) C. 78,1(V) D.45,83(V)
Câu 15:  i = I
0
cos(100

t +
6



A. 0 B.
0

100
I

C.
0
25
I

D
0
50
I


Câu 16: 
 (m/s
2

 (m/s
2
)
A. 0,05s B. 0,15s C. 0,10s D. 0,20s
Câu 17:  

1
và C = C
1


A.


1
B.

3
C.

2
D.

4

Câu 18: 
1



1
 

2
= f
1

1
.

Trang 3

là:

A. 2 V
1
B. 2,5V
1
C. 4V
1.
D. 3V
1.
.
Câu 19: 
 

A. 25 B. 50 C. 100 D. 200
Câu 20: 

A. 30 cm/s B. 30 3 cm/s C. 60 3 cm/s D. 60 cm/s
Câu 21 : 
0
-

2

0


A.

0
2


B. 0 C.

0
 2
D.
2I
0


Câu 22: 



A. 0,005 B. 0.05 C. 0,01 D. 0,004
Câu 23: 


  2   
Câu 24: 
1
= A
1
-

6
) cm và x
2
= A
2
-


2

1
 3 cm
B. 7cm C.15 3 D. 9 3 cm
Câu 25: 
v
max

A. 0,95cm/s B.0,3cm/s C. 0.95m/s D. 0.3m/s
Câu 26: 
1
cos(t)cm;X=2,5 3 
2


1

2 ?
 B.

6
rad C.

3
rad D.

6
rad

Câu 27: 
l


0


A.18 cm. B. 16 cm. C. 20 cm. D. 8 cm.
Câu 28: 
1
= C
2




Trang 4

2

C
1
là:
A. 3
3
. B.3. C.3
5
. D.
2


Câu 29:  

0
cos(



A. 2.U B.
3U
C.
2
3U
D.
3
2U

Câu 30: 
1
= 


U
2


1

A. 20 B.10 C. 22 D. 11
Câu 31: 
      

2
      

40
L
(rad/s) thì U
L
max. Khi

90
C
(rad/s) thì U
C
max . Tìm


R
max .
A. 50

B. 150

C. 60

D.130


Câu 32: 



t
= 2.10
-8
cos
2

A. 5.10
-7
F B. 2,5 F C. 4F D. 10
-8
F

Câu 33: 



A.
3
B. 3 C. 1/3 D.
2

Câu 34: 


3100

3/




A.250W B.300W C.
3100
W D.200W
Câu 35: 
210
84
Po

m
o

0

chu kì bán rã là ?
A.0,92m
0
B.0,06m
0
C.0,98m
0
D.0,12m
0
Câu 36: 
0


2

 A.0 B.1 C.2
D.3


Trang 5
Câu 37: 
2
cos(
Z
C

A. -50V. B. - 50
3
V. C. 50V. D. 50
3
V.
Câu 38: 
F

4
10



2
cos(100

AM

A. L = 1/ (H). B. L = 1/2 (H). C. L = 2/ (H). D. L =
2
/ (H).
Câu 39: 



A.
2
3
A
B.
4
6
A
C.
2
1
D.
4
3

Câu 40: 


2
π
= 10 m/s
2

A. 17 cm. B. 19,2 cm. C. 8,5 cm. D. 9,6 cm.
Câu 41:
Mt
cht
im ang dao ng

vi
phng
trình x  6
c
os10


t
(cm) . Tính
tc

trung
bình ca cht
im
sau
1/4
chu kì
tính
khi bt
u dao ng
và tc 
trung bình sau
nhiu chu
k

dao
ng
A.
1,2m/s
và 0 B. 2m/s và 1,2m/s C.

1,2m/s
và 1,2m/s D. 2m/s và 0
Câu 42: Ti hai im S
1

và S
2

trên mt nc cách nhau 20(cm) có hai ngun phát sóng dao ng theo phng
thng ng vi các
phng
trình ln lt là u
1

 2cos(50

t)(cm) và u
2

 3cos(50

t



)(cm) , tc  truyn
sóng trên mt nc là 1(m/s). im
M
trên
mt nc

cách hai
ngun sóng
S
1 ,
S
2
ln
lt 12(cm) và 16(cm).
S

im

dao

ng
vi
biên
 cc
i trên on
S
2
M là : A.4 B.5 C.6 D.7
Câu 43 :  

1


2

chúng?

A.
21
2
.TTT 
B.
21
112
TTT

C.
2
2
1
22
112
TTT

D.
2
2
2
1
2
TTT 

Câu 44: 



A. 0,628A B. 0,126A C. 6,280A D. 1,570A

Câu 45: 
-4



o

A. 1,5mJ B. 0,09mJ C. 1,08.10
-10
J D. 0,06.10
-10
J
Câu 46: 


Trang 6

-19

tron


A. 20% B. 30% C. 70% D. 80%
Câu 47: 

1
= a
1
cos(40t + /6) (cm), u
2

= a
2
cos(40t + 


 : A. 4 B. 3 C. 2
D. 1
Câu 48: 
2
N/cm,



A. 0,02 s. B. 0,04 s. C. 0,03 s. D. 0,01 s.
Câu 49: Dao 

0


A. 120
0
. B. 105
0
. C. 143,1
0
. D. 126,9
0
.
Câu 50: 
1




2


2


 A.
84 

(cm) B. 16 (cm) C.
42 

(cm) D.
44 

(cm)


HƯỚNG DẪN GIẢI CHI TIẾT ĐỀ THI THỬ ĐẠI HỌC VẬT LÝ SỐ 007 - Năm 2013
Câu 1:

)(cos
2
2
2
0


 t
C
Q
E
đ

)(sin
2
2
2
0

 t
C
Q
E
t
.
E
t
= 3E

=>. sin
2
(t +) = 3cos
2
(t +) > 1 - cos
2
(t +) =3cos
2

(t +)
> cos
2
(t +) = ¼ >cos(t +) = ± 0,5


t
1
= t
M1M2

2
= t
M2M3

t
= 3E

nên

1
= 10
-4
s > chu kì T = 6.10
-4
s Chọn C
Câu 2:
Giải: 
0


là R và 
P = P
2
R/U
2
Theo bài ra ta có

Trang 7
P = 36P
0
+ P
2
R/U
2
(1) P = 144P
0
+ P
2
R/4U
2
(2) P = nP
0
+ P
2
R/9U
2
(3)

0
(4)

 36)P
0
(5)
Từ (4) và (5) ta có
n = 164. Chọn A

Câu 3:
Giải: W

=
AK
eU
mv
mv

22
2
0
2

h
eU
mv

2
2
0
>
)(
22

2
0
2
AKhAK
UUeeU
mv
mv


=> v =
6
31
19
10.789,1
10.1,9
)1,45(10.6,1.2
)(
2





hAK
UUe
m
(m/s)
Câu 4:

max

 0) =
h
eU
mv

2
2
max0

ta có hf
1
= A +
2
2
1
mv
= A + eV
1

1
2
1
3
2
3 eV
mv

(2)
h(f
1

+ f) = A +
2
2
21
mv
= A + eV
2
= A + 7eV
1
(3) hf = A +
2
2
mv
= A + eV (4)
 (1) : hf = 6eV
1
=> 6eV
1
= A + eV=> eV = 6eV
1
 A = 3eV
1
Do đó V = 3V
1
Câu 5:

0
, Z
L
, Z

C

 
2



1
= 70 thì I
1
= 0,75A, P
1
= 0,928P = 111,36W
P
1
= I
1
2
R
0
(1) => R
0
= P
1
/I
1
2
 198 (2)
I
1

=
2222
10
1
)(268
220
)()(
CLCL
ZZZZRR
U
Z
U





Suy ra : (Z
L
 Z
C
)
2
= (220/0,75)
2
 268
2
>  Z
L
 Z

C
  119 (3)
Ta có P = I
2
R
0
(4)

22
20
)()(
CL
ZZRR
U
Z
U


(5)
P =
22
20
0
2
)()(
CL
ZZRR
RU

=> R

0
+ R
2
 256 => R
2
 58 R
2
< R
1
=
2
 R
1
= - 12
Phải giảm 12. Chọn C
Câu 6:

00
0
1
10
UU
LL
I C E r C
   
A
Câu 7:
+ thời gian 
q = q
0

=> q =
0
2
q

1
4


  


Trang 8

2
3




Mà:
1 2 1 1
12
22
3
;
4
t
tt
t

  
  
   
      


Câu 8:
Khi t = 0 x = 0. Sau t
1
= 0,5s S
1
= x = A/2. V vòng tròn Ta có t
1
= T/12  Chu kì T = 6s

2
=12,5 s = 2T + 0,5s 
2
= 8A + S
1

Câu 9:
Giải. Thi gian lò xo nén là T/3
 


Câu 10:
Giải:  
kì: T = 0,1s.Do 
 v

max
Đáp án A
Câu 11:
Giải: 
R
2
+ (U
d
 U
C
)
2
= U
AB
2
Theo bài ra 25
2
+( 25  175)
2

2

; 
R
U Ur
U


Ta có (U
R

+ U
r
)
2
+(U
L
U
C
)
2
= U
2
(1)
U
r
2
+ U
L
2
= U
d
2
(2)

r
= 24 V; U
L
= 7V 
R
U Ur

U

= 7/25.
Câu 12:
Bài giải: 
2
 W
1
= - 13,6/4 (eV)  (- 13,6) (eV) = 10,2
(eV)
 10,2 (eV) = 2,4 (eV). Chọn A
Câu 13

2
N
0
=
2
2fN
0
= U ( do r = 0)

Do I
1
= I
2
ta có:




2
1
1
2
2
1
)
2
1
2(
Cf
LfR
f



2
2
2
2
2
2
)
2
1
2(
Cf
LfR
f





> f
1
2
[R
2
+4
2
L
2
f
2
2
+
2
2
22
4
1
fC

- 2
C
L
] = f
2
2
[R

2
+4
2
L
2
f
1
2
+
2
1
22
4
1
fC

- 2
C
L
]


Trang 9
))(2()(
4
1
2
2
2
1

2
2
1
2
2
2
2
2
1
22
ffR
C
L
f
f
f
f
C


>
)2(4
11
222
2
2
2
1
R
C

L
C
ff


(*)

Z
E
Z
U


I = I
mac
khi E
2
/Z
2

22
2
)
2
1
2(
Cf
LfR
f





y =
2
222
2222
2
4
1
4
1
f
C
L
fC
fLR 


=
22
2
2
422
4
2
4
1
1
L

f
C
L
R
fC







max


2
1
f

0
= 2
2
C
2
(2
)
2
R
C
L




2
0
1
f
= 2
2
C
2
(2
)
2
R
C
L

(**)
 (*) và (**) ta suy ra

2
0
2
2
2
1
211
fff


hay
2
0
2
2
2
1
211
nnn

>
22
2
12
0
22
12
2.nn
n
nn


Chọn B
Câu 14:
u
AB
= u
AM
+ u
MB


Mà u
MB
= - u
BM
= - -- 
2 2 2 2 0
0 0 0 0 0
2 . os 40 78,150 2.40.50. os60
AB AM MB AM MB
U U U U U c Vc

       

Câu 15:

)
6
100()
6
100cos(
100
)
6
100cos(
000
0
0










tdt
I
dttIidt
t
t
t
t
t
t

Khi t=t
0
thì i=0 > t
0
=
s
300
1
.
Còn t = t
0
+ T/4 = 1/300 + 1/200 = 5/600 (s)
Suy ra q =





100
)]
6
100sin([
100
00
0
I
t
I
t
t

Chọn B.
Có thể giải theo cách khác 
0
i
0
= 0, kh
0
= 0

0

0
= I

0
/ = I
0
/100


Câu 16:
Ta có v
max
= A = 3 (m/s) và a
max
= 
2

2
)
>  

3,0
(m)
)
Khi t = 0 v = 1,5 m/s = v
max
/2 

= W/4 
t
= 3W/4

Trang 10

2
3
24
3
2
0
2
2
0
A
x
kA
kx


2
3A
= Acos > sin  =
-
6


) =

3,0
-
6

)
Gia tốc a = - 

2
x = - 30πcos(10πt -
6

) (m/s
2
)
- 30-
6

) = 15 -
6

) = -
2
1
= cos
3
2


-
6

= ±
3
2

 > t =
10

2
30
2
60
1 k


t
1
=
12
1

t
2
= -
20
1
+ 0,2k = -
20
1

15 (m/s
2
): 0,0833s, 0,15s, 0,2833s; 0,35s
Giá trị đầu tiên của t = t
min
: = 0,0833s
Đáp án khác với bài ra.
Có thể dùng vòng tròn lượng giác:


0



2
); T = 0,2s
t = T/12 + T/3 = 5T/12 = 1/12 = 0,0833 s

Câu 17:
Giải: 
1 2 1 1
1
2
3
2 2 2
C C C C
LC
Z Z Z Z
ZZ

  
(1)
Do C
1
> C
2
nên Z
C1
< Z

C2
: 
1
> 0 => 
2
< 0

1
=
4


Ta có :
1
1
tan tan( ) 1
4
LC
ZZ
R



  
=> Z
L
-Z
C1
= 100 (2)


L
-
2
3
Z
L
= 100 => Z
L
= 300 =>
300 3
()
100
L
Z
LH
  
  

Câu 18:

1
thì :
AAAmvAhf 5,1
2
1
2
1
2
max01




11
VeAhf 
hay
AeV
2
1
1



2
=f
1
+f thì
AAAVeAVeAhfhfhf 5,35,0.55
1212



max
VeAhf 



M
0
M





Trang 11

11max
maxmax1max
22
5,15,35,3
VVeAVe
VeAAAVeAhfAVeAhf



Câu 19:
 < 0,1)

0
= mgl(1-cos) = 2mglsin
2
2

 mgl
2
2




])(.2[

2
])([
2
222


mglmgl
(1)

A

= F
c
s = 0,001mg(2 - )l (2)

c


])(.2[
2
2


mgl
= 0,001mg(2 - )l
)
2
  + 0,0004 = 0  = 0,101   = 0,002

50

002,0
1,0




. Chọn B.
Câu 20:
Giảit =
Ts
3
1
)(
6
1




3

1
=
2
3A

2
= -
2
3A

. Do đó v
TBmax
= 60 3 cm/s

Đo đó v
TBmin
= 60cm/s
Câu 21
Giải: Khi t = t
0
= 0 thì i
0

2
T

i = I
0

4
T
.

q
1
= I
0
/

2

= I
0
/ 

1
+ q
2
=
2I
0


Câu 22:
Giải
1
và I
2


1
2
R = 0,05U
2
I
2



Trang 12
k =

005,0
40.50
200.05,0
05,0
1
2
2
1
1
2

RI
U
I
I
U
U
. Chọn A.

Câu 23:
Giải
LC

2
1
.


C =
d

S


4.10.9
9
 
Chọn C
Câu 24: 
1
= A
1
-

6
) cm và x
2
= A
2
-

2

1

A.18 3 cm B. 7cm C.15 3 D. 9 3 cm
Giải: 

6
sin
sin

6
sin
sin
2
2




A
A
A
A


A
2
  >  = /2
A
2max
= 2A = 18cm > A
1
=
39918
2222
2
 AA
(cm). Chọn D
Câu 25: 
v

max

A. 0,95cm/s B.0,3cm/s C. 0.95m/s D. 0.3m/s
Giải: :
mgS
mv
A
mv
mv
Fms


222
22
2
max
=> v
2
=
2
max
v
- 2gS
> v =
9497,0902,01.0.8,9.05,0.212
2
max
 gSv

m/s

v  0,95m/s. Chọn đáp án C
Câu 26: 
1
cos(t)cm;X=2,5 3 
2


1

2 ?


6
rad C.

3
rad D.

6
rad
Giải: 
)sin(
sin
)sin(sin
2
1
2
1








A
A
A
A


A
1
  >  = /2
A
1max
=
55,2.35,2
222
2
2
 AA
(cm)
O
 /6

A

A
1

A
2

2


O


A


A
1
A
2


Trang 13
sin( - 
2
) =
2
1
max1

A
A
>  - 
2

=
6

> 
2
=
6
5

Chọn D
Câu 27: 
l


0


A.18 cm. B. 16 cm. C. 20 cm. D. 8 cm.
Ta có: s
0
= l
0
=40.0,15= 6cm


Ta có:
Góc quét:
2 2 4

3 3 3

T
t
T
  
  
      


1

S
max1
= 2A =12cm
Trong 
1

thì S
max2
= 2.3 = 6cm

max
=

S
max1
+ S
max2
= 18cm
Câu 28: 
1

= C
2




2

C
1
là:
B. 3
3
. B.3. C.3
5
. D.
2

Giải: 
0


2_

W
0
=
0
2
0

2
36
2
2
2
C
EC
CU


Khi i =
2
0
I

L
= Li
2
=
0
0
2
0
9
424
1
C
WLI




C
=
0
0
27
4
3
C
W


W
C1
=W
C2
= 13,5C
0


W = W
L
+W
C1
= 22,5C
0

W =
0
2

10
2
11
5,22
22
C
UC
UC

> U
1
2
= 45 > U
1
= 3
5


Câu 29:
Ta có U
R
= IR và U
C
= IZ
C

L
= Z
C
.


RMAX
= U; Ucmax =
c
UZ
R
; Ta có ULmax =
22
c
U R Z
R



max
max
2
R
L
U
U

thì ta có
22
43
c
ZR

M
N


-6 0 6

3


3

Trang 14

max
max
2
L
R
U
U

thì ta có
max
33
cc
Z R U U  
B
Câu 30:
Giải:
1
và N
2


Ta có

2
1
220
110
2
1
N
N
N
2
= 2N
1

1
= 110 x1,2 = 132 vòng


264
110
2
2
264
110
2
1
1
2
1





N
nN
N
nN
(2)
Thay N
1
. Chọn D
Chú ý: 

1
= (N
1
-n)e
0
 ne
0
= (N
1
 2n) e
0

0

dây.
e

2
= N
2
e
0;

264
110
22
2
1
2
1
2
1
2
1
2
1




N
nN
U
U
E
E
e

e
N
nN

Câu 31:


L
=
2
1
2
LR
C
C


2
2
c
LR
C
L




L

C


0
2

Rmax


0
=
60
CL
  

C
Câu 32:


22
0
11
22
CU CE


L
= 2.10
-8

2 8 8
1

2.10 10
2
CE C F

   

Câu 33:

max

2
s
0
; s
0

0

0
=> s =
0
3
s

2
s 
ax
3
m
a

a


Câu 34:

+ tan
3
3
LC
LC
ZZ
Z Z R
R


   
+ P =
22
2
22
4
( ) 4
LC
U R U
U RP
R Z Z R
  


+ Pmax =

2
2
U
Rm
 ZC =
3R
suy ra Pmax =
4
200
23
RP
W
R


Câu 35:



0
/16.
m

pb
/ m

po
= N

pb

.M

pb
/ N

po
.M

Po
suy ra m

pb
=m

po
.N

pb
.M

pb
/ N

po
.M

Po
= m

0

.
15N

0
.206
16N

0
210
=0,92m

0
.

Trang 15
Câu 36:

sini

ghv
= 1/n

v
=1/ 2 nên i=i

ghv
=45
0

 


v
<n

L
<n

C

nên i

ghv
>I

ghL
>I

ghc

 
Câu 37:
0
00
100
2
AB
C C R
U
Z R U U V    



0
50
2
R
R
U
uV
do
C
u

R
u

0
3
50 3
2
C
C
U
uV   

Câu 38:

U
AM
=
22

22
()
AB C
LC
RZ
R Z Z


U

AM

2 2 2 2
2
( ) 2 200
C L C L C L
R Z R Z Z Z Z Z L H

          

Câu 39
Giải. Khi W

= W
t
> W
t
= W/2
22
1

2
22
kAkx

> x =
2
2A


2
2A


0:
m
kA
v
kA
W
mv
đ
222
1
2
2
2
0
2
2
0






0
=
4
2
2
1
)
2
2
(
2
1
00
A
l
A
l 

0


m
k
m
k 2'




2
=
2
2
0
2
0
'

v
x 
=
8
3
48
2
2
8
222
2
2
AAA
m
k
m
kA
A



4
6A

Câu 40:

cm
ll
A 8
2
3248
2
minmax






cmm
k
mg
l 1616,0
25
10.4,0



O


 



Trang 16

cmlAllAlll 2416848
max00max




NmaF
qt
4,01.4,0 
 

cmm
k
F
x
qt
6,1016,0
25
4,0



Câu 41:

Khi
0t
thì
cmx 60cos6 

Sau
4
T
t 

1/4
chu kì
scm
t
s
v /120
4/2,0
6



scm
T
A
t
s
v /120
2,0
6.44



Câu 42:

cm
f
v
4
25
100




2
1
12


k
dd



1
4
1216
12






dd

2

5
4
200
12





dd


2
-4,5; -3,5; -2,5; -1,5; -0,5; 0,5
Câu 43 :

1
, 

2

A.
21
2

.TTT 
B.
21
112
TTT

C.
2
2
1
22
112
TTT

D.
2
2
2
1
2
TTT 

C
Câu 44:
A
rR
NBS
rR
e
I

c
126,0
41
10.1,0.2,0.10
2
max
max









Câu 45:

W
L
CU
R
RII
RRIP
5
4
29
2
0
2

0
2
0
2
10.9
10.2,1
6.10.3
2
2,0
22
)
2
(






:
)(10.08,110.3.10.2,12.10.92.10.9
109455
JLCPTPtA




Câu 46:

13

10
e
I
nenI
ee


15
19
3
10.5
10.8,9
10.9,4





P
nnP
ff


Trang 17

13
15
10.5
100
10.5



13
electron

%808,0
10.5
1010.5
13
1313



Câu 47: AD CT : 





2
)12(
2
)12( 








AB
k
AB
;
cm
f
v
6
20
120








2
3
6
)12(18
2
3
6
)12(18





k

 k 
CÁCH KHÁC
cm
f
v
6
20
120








2
12
12

 kdd

6
1
2
62
12





 kk
dd





24,1
6
21818
12





dd
;
24,1
6
18218
12






dd


07,14,124,1
6
1
24,1  kk

Câu 48:

m
k

=0,2s


Câu 49: 

0


A. 120
0
. B. 105
0
. C. 143,1
0
. D. 126,9
0
.

2A=A
1
+A
2

Vì A vuong góc A
1
nên A
2
=
22
2 1 2 1 2 1
( )( )A A A A A A   


3A=4A
1

2
Tan

= A
1
/A = 3/4
0
36,9



1

và A
2
la 126,9
0

Câu 50: 
1



2
= 

2


 A.
84 

(cm) B. 16 (cm) C.
42 

(cm) D.
44 

(cm)


1
+ m


2

2



1
+ m

2
).v
2

/2
  

max
= k/m

1,2
.A =16 cm/s)

Trang 18
 


1
=2 m


1
/k 

1
= A

1
=
v. m

1
/k = 4cm.


2


2
= v.T

1
/4 =2  -4 cm.






×