Введение в аналитическую динамику. Кирсанов А.А. - 138 стр.

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138
Ãëàâà ïÿòàÿ
r
prm
r
L
==
&
&
,
m
p
r
r
=
&
,
θ
θ
θ
pmr
L
==
&
&
2
,
2
mr
p
θ
θ
=
&
,
z
pzm
z
L
==
&
&
,
m
p
z
z
=
&
.
Ñîñòàâèì ôóíêöèþ Ãàìèëüòîíà
==
LqpH
ii
&
()
zrVpp
r
p
m
pp
r
p
m
zrzr
,,
1
2
111
22
2
222
2
2
θ
θθ
+
++
++=
.
Îêîí÷àòåëüíî ïîëó÷èì
()
zrVpp
r
p
m
H
zr
,,
1
2
1
22
2
2
θ
θ
+
++=
. (5.4.20)
Ñîñòàâèì êàíîíè÷åñêèå óðàâíåíèÿ Ãàìèëüòîíà
r
m
p
p
H
r
r
&
==
,
θ
θ
θ
&
==
2
mr
p
p
H
,
z
m
p
p
H
z
z
&
==
è
r
p
r
V
mr
p
r
H
&
=
+=
3
2
θ
,
θ
θθ
p
VH
&
=
=
,
z
p
z
V
z
H
&
=
=
.
3. Ñôåðè÷åñêèå êîîðäèíàòû.
Âûðàçèì äåêàðòîâû êîîðäèíàòû ìàòåðèàëüíîé òî÷êè ÷åðåç ñôå-
ðè÷åñêèå êîîðäèíàòû (ñì. çàäà÷ó ¹11)
=
=
=
θ
ϕθ
ϕθ
cos
sinsin
cossin
rz
ry
rx
. (5.4.21)
138                                                          Ãëàâà ïÿòàÿ

      ∂L                             pr
          = mr& = pr ,        r& =      ,
      ∂r&                            m
      ∂L                       p
        & = mr 2θ& = pθ , θ& = θ 2 ,
      ∂θ                      mr
      ∂L                             pz
          = mz& = p z ,       z& =      .
      ∂z&                            m
      Ñîñòàâèì ôóíêöèþ Ãàìèëüòîíà
      H = ∑ pi q&i − L =

          1 2 1 2         2    1  2 1 2        2
      =     pr + 2 pθ + p z  −    pr + 2 pθ + pz  + V (r ,θ , z ) .
          m     r            2m       r          
      Îêîí÷àòåëüíî ïîëó÷èì
              1  2 1 2         2
      H=         pr + 2 pθ + p z  + V (r,θ , z ).              (5.4.20)
             2m      r           
      Ñîñòàâèì êàíîíè÷åñêèå óðàâíåíèÿ Ãàìèëüòîíà
      ∂H pr        ∂H   p          ∂H pz
         =  = r& ,    = θ 2 = θ& ,     =  = z&
      ∂pr m        ∂pθ mr          ∂p z m
è

      ∂H   pθ2 ∂V             ∂H ∂V            ∂H ∂V
         =− 3 +    = − p& r ,   =   = − p& θ ,    =    = − p& z .
      ∂r   mr   ∂r            ∂θ ∂θ            ∂z   ∂z

     3. Ñôåðè÷åñêèå êîîðäèíàòû.
     Âûðàçèì äåêàðòîâû êîîðäèíàòû ìàòåðèàëüíîé òî÷êè ÷åðåç ñôå-
ðè÷åñêèå êîîðäèíàòû (ñì. çàäà÷ó ¹11)

      x = r sin θ cosϕ 
                        
      y = r sin θ sin ϕ 
                          .                                      (5.4.21)
      z = r cosθ        
                        