, . t , (140.1), s=x:
= cos(w0t+j). (141.1)
(140.4) (140.5), v
F=ma, , (141.1) (141.2)
F= -mw 20 x.
, ( ).
, ,
, F,
(141.3) (141.5), :
, , .
(141.4) (141.6) , 2w0, . . , .
. 200 , . <sin2a>= <cos2aa>=1/2, (141.3), (141.5) (141.7) , <> = <>=1/2E.
.
, , (140.6):
. , , ( , ; . 146).
, - . ,
.
. , , , . , , ( ), , , , . , , , .
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s , , d=const , w0 , . . d=0 ( ) .
(146.1)
s=e-du (146.2)
u=u(t). (146.2) (146.1)
(146.3) . , :
w2=w20-d2 (146.4)
( (w2-d2)>0, ). (142.1)
= 0cos(wt+j)
(. (140.1)).
, (146.1) (d2<<w20)
s=A0-dts(wt+j), (146.5) = 0 -dt (146.6)
,
a 0 . (146.5) .208 , (146.6) . t=1/d, , .
, , , . , ( ) (. 208).
(146.4)
A(t) A(t+T) , , ,
,
; Ne , . .
Q,
( (d2<<w20), 0 ).
(146.8) , Ne, .
, , ( ) ( ).
1. . (. 142) , F=-kx, , . .
r ; .
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w0=Ök/m (. (142.2)) ,
d=r/(2m), (146.10)
(146.1) , :
(146.1) (146.5) ,
=A0-dtcos(wt+j) w=Ö(w20-r2/4m2) (. (146.4)).
,
(146.8) (146.10), Q =1/rÖkm.
19. ,
, - (, , ..). . . , . . . ( , . . ), . . , ( . .). . . , .
, ( ) . ., , (.). . .
. . . , . . . . . . . . .
20.
, , , . , .
J = ml 2, (142.8)
l .
, , , , (142.8) (142.7),
T=2pÖl/g. (142.9)
(142.7) (142.9), , L l , . , , .
21.
, , (.201).
, (18.3)
, , l , Ft=- mg sina mga ( , Ft a ; sinaa , . . ).
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(142.4)
w0=Ö mgl/J. (142.5)
(142.1), (140.1) :
a=a0cos (w 0 t +j). (142.6)
(142.6) , w0 ( (142.5))
= 2p/w0=2pÖ J /(mgl)=2pÖ L/g.
(142.7)
L = J/(ml) .
' , L, (. 201). (16.1),
. . ' . ' : , .
22. . , , , .
(. 140). (.203). a 1 2 w0, (j2-j1) .
, -
= 1 + 2 = cos(w0 t +j). (144.1)
(144.1) j
, , , , . (j2-j1) .
(144.2) (j2-j1):
1) j2-j1=2mp (m = 0, 1, 2,...), A=A 1 +A 2, .. ;
2) j2-j1= (2m+1)p (m=0, 1, 2,...), A = │A 1 -A 2 │, .. .
23. ( 22)
, . . , , .
, w w+Dw, Dw<<w. , :
, Dw/2<<w,
. Dw<<w, , , , coswt .
w, , :
A , ( ), .. : w=Dw.
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T=2p/Dw.
(144.3) . 204, (144.3), (144.4) .
( (. 158)) . , . .
s=f(t) , , , w0:
(144.5) , .
, w0, 2w0, 3w0,..., ( ),
, . . .