6
.


22787.unknown
P.*/44
λ——.
T ——.





P.*/44
.——

y
x
O
x1
x2
u
A
λ
P.*/44
y
x
O
x1
x2
u
A
λ
6
6-1: t=0xt=1/2s. T>1sA. (A=0.01m)

6
6-2: u = 20 m/sx. Ay = 3cos 4t (1) A(2) A5mB.
A
B,
S
u
u
P.*/44
6-4: S y = Acos( t -2x/). S
P.*/44
2.
.
6.5.1


6
6-6: S1S2d = 30mx S1O. . x1 =9m x2=12m. .

S1S2
x1
—— (1)
x2
—— (2)
(2)-(1)
(1)


P.*/44


“”
6.6.4
(1)

(1)
uST
:
:
.
:
:

P.*/44
P.*/44

1 120
10 130
10



P.*/44
20Hz.
6.8.3
.

P.*/44
().
20Hz.
6.8.3
.