6. , .
, , d l
d f = ki d l ´ B (46.1)
(k , i , , d l).
(46.1)
d f = kiB d l sin a (46.2)
a d l (. 84,a). , d l .
. , , . , , , (. 84,6). , , .
. b (. 85), i 2 , . a i 2 1 .
, (46.2) i 1
(46.3)
f 12, i 2 . , , .
(46.3) (38.2 ), k = 1. ,
d f = i d l ´ B (46.4)
d f = i d l sin a. (46.5)
7.
, , , . , , , , , . , , , , , .
(46.4) d l
d f = i d l ´ B (47.1)
i d l S j d l,
d f = S d l j ´ B = j ´ B d V
d V , d f. d f d V, , . . , :
f . = j ´ B (47.2)
j = en u, ,
f . = n ' u ´ .
, , . n, , , f ./ n = ' u ´ .
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, , ', u ,
f = ' u ´ (47.3)
(47.3) .
, :
f = ' E + ' u ´
f = e ' uB sin a (47.5)
a u B. , , , .
, u B. ' , u ´ .
f u ´ (. 86).
, . , , .
. (47.3) (47.1) , . . ( )
u 0 : .
(47.3), , d l, :
(47.6)
u = u 0 + u.
(47.6) . (47.2 f . = j ´ B). , , .
, , (47.1 d f = i d l ´ B), , . , ze z .
, , υ, u. υ + u.
f _ = (υ + u) ´ ] = υ ´ u ´ ,
d f _ = z υ ´ d N z u ´ d N,
z d N d l, u . d N .
ez. υ,
f + = z υ ´
, , d l,
d f + = z υ ´ d N.
d l , d f _+ d f +, , ,
d f = d f _+ d f + = z u ´ d N
d f = i d l ´ B. υ, .
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8.
, , . , . (. 87), , b, , (46.5 d f = i d l sin a) sin a = 0.
f = iBa, , f ' . ,
ab S, iS p m.
(48.1)
, , m . . 88.
f 1 = f 3 = iBa, f 2 = f 4 = iBb. . , . , ; , . 180 ( ), , , .
(M = p m ) . d h (. 89, ). d l 1 d f 1 = iB d l 1 sin a 1, . d l 2 d f 2 = iB d l 2 sin a 2, . . 89 , d l 1 sin a 1 = d l 2 sin a 2 = dh, . , d f 1 d f 2 ,
,
b . b ×d h d S. ,
.
, , , , :
,
(48.1).
(. 90) : B ^ || . B ^ , .
|| sin a (a p m ). , (48.1 M = p m ):
(48.2)
, p m , (48.2)
(48.3)
a p m d a, ,
(48.5)
, . , (48.5) W, ,
, :
.
const = 0,
(48.6)
, .
. , . ( 91,).
d f, , , .. d l. , , (. 91,6).
f , , . , ( ), , , f. p m , d f f (. 91,). .
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, f:
(a = const). , , = (),
(48.8)
, , . p m (a = 0), , .. ( ). p m (a = p), , . . .
, , . , = p m´ p m .
9. ,
, , . , , .
, . , (. 92). , . , , f = iBl, l . d s
d A = f d S = iBl d s
l d s d S (. 92), a Bl d s = B d S d .
d A = i d (49.1)
d , .
. d l ,
( d l d s ).
f . , a, a
d A = f cos a d s = iB n l d s,
B n = cos a l d s. B n l d s d , . (49.1).
(), . (49.1) , , .
. . . , , (. ). , , , . . . ,
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(49.1).
, . , , (. 93; ). , 12, . , 1 . i
12 (d A = i d ). 12 0 , .
A 1 = i ( 0 + )
, 21, . 2 .
, 21, 0 , . ,
A 2 = i ( 0 + ).
, ,
= 1 + 2 = i ( 0 + ) i ( 0 + ) = i ( )
D . ,
= i D (49.2)
, . , . , , m , , , :
= W W = p m ( p m ) = 2 p m .