, :
d = d = Fdr = (d/dt)dr = u×d[(mu/Ö(l u2/2)] = u{d(mu)/Ö(l u2/2) + mu×dÖ(l u2/2)} = u{m×du/Ö(l - u2/2) + m×u×(u/2)×du/Ö(l u2/2)3} = m×u×du/Ö(l u2/2) + m×u3×(du/2)/Ö(l u2/2)3 = [m×u×du - m×u3×(du/2) + m×u3×(du/2)]/Ö(l - u2/2)3 = m×u×du/Ö(l u2/2)3 = d[m2/Ö(l u2/2)] Þ
= m2/Ö(l u2/2) + const;
u = 0, = 0, m2/Ö(l u2/2) + const = 0, const = - m2
= m2/Ö(l u2/2) - m2 = m2[(1/Ö(l u2/2) 1].
u << , Ö(l u2/2) 1 - u2/22 mu2/2 , , .
, , ,
, E = m2 - :
= - .
= m2/Ö(l - u2/2) - .
m = m2, , Dm D , D = Dm×2 - ().
.
() , . . . , , 2.
, , , , , :
= Smi2 - 2, - . .
.
,
2:
= m2/Ö(l u2/2) 2 2 u2/2 = m24 , = mu/Ö(l u2/2) = u/2 Þ
2 22 = m24 = const, 2/2 2 = m22 = Inv
, , , // - . - , , - , , .
|
|
:
27. : . . -.
.
. ( ), ( ).
, , - , - , k .
.
, :
1) , , ;
2) , .
.
1. , .
2. , ( ), .
:
,
w - , k - , - .
, k .
.
, ( ), , m. , c (. ).
:
Fc , Fy
Fc = − cv, Fy = − kx,
ma + cv + kx = 0
k , a .
:
ω , ζ .
x = e λ t ,
,
ζ.
.
, , :
.
, , :
, .
|
|
,
.
c 1 c 2 :