, , , , , , , . . .
, n , 1, m2,..., n v1, v2,..., vn. F'1, F'2,..., F'n , , a f1, f2,..., Fn . n :
d/dt(m1v1)=F'1+F1,
d/dt(m2v2)=F'2+F2,
d/dt)mnvn)= F'n+Fn.
,
d/dt (m1v1+m2v2+... + mnvn) = F'1+F'2+...+ F'n+F1+F2+...+ Fn.
,
d/dt(m1v1+m2v2 +... + mnvn)= F1 + F2+...+ Fn,
dp/dt=F1+ F2+...+ Fn, (9.1)
.
, , .
( )
: , . . .
, .
, , , .
( ) , . -
mi ri - i- ; n ;
.
, p i =mi v i,
,
p = m v c, (9.2)
. . .
(9.2) (9.1),
mdvc/dt= F 1+ F 2+...+ F n, (9.3)
. . , , , . (9.3) .
(9.2) , , .
.
m1, m 2 ,..., mn, v 1, v 2,..., v n. F '1, F '2,..., F ' n , , a f 1, F 2,..., F n , . , , ; , , f 1, f 2,..., fn. v<<
|
|
:
, dt , d r 1, d r 2,..., d r n. , , dri = vidt, :
,
(13.1)
dT .
, , . . d (. (12.2)).
(13.1) ,
. ,
d(T+ )=dA. (13.2)
1 - 2
. . , .
, (13.2) ,
d(+) = 0,
+ = E=const, (13.3)
. . . (13.3) : , , , . . .
: .
, . . .
, , .