, m , :
. (1.3.38)
, , . , , . .
, :
,
, i - , .
, , , , (). :
, (1.3.39)
.
, , , , .
, . , , ,
. (1.3.40)
(1.3.40) .
.
14. 1 . 1 . = 2 ×/4, = 3 ×/2, = 2 ×/.
: ;
= 2 ×/4, = 3 ×/2, = 2 ×/;
m = 1 .
: .
. (1.3.40):
= F / m,
, (1.3.23), :
, (1.3.41)
Fx, Fy, Fz , (7.3), :
Fx = dpx / dt, Fy = dpy / dt, Fz = dpz / dt. (1.3.42)
px = t 3, py = Bt, pz = C.
, (7.5), :
Fx = dpx / dt = d (t 3)/ dt = 3 At 2 = 6 (),
Fy = dpy / dt = d (Bt)/ dt = B = 3 (),
Fz = dpz / dt = d (C)/ dt = 0.
(1.3.41), (1.3.40):
F = (62 + 32)1/2 = 6,7 ().
= 6,7 (/2).
: 6,7 /2.
15. 2 3 4 / 2 / . , ) ; ) .
: m 1 = 2 , m 2 = 3 ,
v 1 = 4 /, v 2 = 2 /.
: u.
. ) , .
, u.
|
|
v 1 v 2 u
m 1 m 2 m 1+ m 2 x
x , . , (1.3.39). x:
m 1 v 1 + m 2 v 2 = (m 1+ m 2) u,
:
u = (m 1 v 1 + m 2 v 2)/(m 1+ m 2) = 2,8 (/).
) :
v 1 v 2 u
m 1 m 2 m 1+ m 2 x
, . x:
m 1 v 1 m 2 v 2 = (m 1+ m 2) u, u = (m 1 v 1 m 2 v 2)/(m 1+ m 2) =
= 0,4 (/).
: 2,8 /; 0,4 /.
16. - 1 , = 1 /3, = 2 /, = 3 . , , , 1 .
: ;
= 1 /3, = 2 /, = 3 ,;
m = 1 .
: , v.
. (1.3.40):
= = =
= .
(1.3.23), (1.3.22):
= d (At 3)/ dt = 3 At 2 = 3 (/),
= d (Bt)/ dt = B = 2 (/),
= d (C)/ dt = 0.
= (32 + 22)1/2 = 3,6 (/).
: = ; v = 3,6 /.