V lekcija
of 7
Transcript of V lekcija
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je
n :
2
1
.
n
i i
i
J m r
=
=
je
2 ,J r dm= . r
x, y, z.
J
CJ m
a 2 .CJ J ma= +
R 2mR
R 21
2
mR
l
21
12ml
l
21
3ml
R
22
5mR
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M
, r
F
():
M r F=
M
r
F
.
sin ,M Fr F l= =
- r
F
; sinr l= - .
.
:
L r p r mv= =
r
- ; p mv=
- ; L
-
r
p
.
sin sin ,L rp mvr pl = = =
- r
p
, l - p
.
z
zL ,
. zL z.
rFO
A
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z .
1m , 2m , , nm 1r , 2r , , nr ,
. , im
ir iv
()
1 2
1 2
... .n
n
vv v
r r r= = = =
:22 2
21 1 2 2.
1
1...
2 2 2 2
nn n
k rot i i
i
m vm v m vE m v
=
= + + + =
nn rv =
22 2 2
,
1 1
1
2 2
n n
k rot i i i i
i i
E m r mr
= =
= =
2
1
n
i
i
mr J
=
= - z , :
2
, .2
k rot
JE
=
.
kdA dE = .
zdA M d = ; ( )2 / 2kdE d J J d = = ; Md J d = ;d d
M Jdt dt
= .
/d dt = /d dt =
M J = - .
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()
ir iv
. i i i iL m v r=
:
1
.
n
i i i i
i
L m v r
=
=
: i iv r= ;2
1
.
n
i i
i
J m r
=
=
21
1
n
i
i
L m r J
=
= =
.
:
dL dJ
dt dt
=
/d dt = . M J= dL
Mdt
= -
.
: 0M= / 0dL dt =
L const= - :
.
.
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m J
dr
vdt
=
d
dt
=
d v
adt
=
d
dt
=
F
M
p mv=
L J=
F ma=
d pF
dt=
d LM
dt=
sdA F ds= dA Md =
2
k2
mvE = 2
k,rot2
JE =
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.
.
: ( , , , ) , .
:
E = - ( .
[N/m2]).
.
l F
l E ES
= = = ESF l k l
l= =
: l ( k ).
.
,
x .
:
l
l
=
l - .
:
I d
d
=
d - .
% : 100%ll
=
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() .
.
( )
1 .
( ( ) ) 2
.
, B,
CF. 0,2% 3 -
. CD, . ,,,,.
.
, .
(D) . 4 .
.
, .
:
0
,
l
pE A Fdx
= =
x- , 0 l . /F kx ESx l= = :
( )2
0 0
1
2
l ly y
p
E S E S ESE x dx x dx l
l l l
= = =
. ( )2
l .
F0
123
4
A
BC
D
E
