y x y x W x f x x
ux
y x x y x x W x f x x
p
y x x x x dx x x x dx
x A t p
x t
t
c c x t t t
x t
x A t p
x t
x x
x A t B t
p
x t t t t t
x t
x A t
p
x t
x t c t c t t
x t t t t
t t t
x C t F
Ck m
x x x
F
x x t
m
p
F
x t t
p
x A
B
xx t
F t F t m
p
x A t B t A B A B
p
x A t B t A B A B
p
x A t t A B A B
x t t t
x A t t A B A B
x t t t
p
x A B
x A t B t A B A B
x t t t t t t
p
x A t B t A B A B
x t t t t t t
p
x A t B t A B A B
x t t t
p
x A t B t A B A B
x t t t t t t
x t A t B t
mx cx kx F t m c k F
A B t t
A B A B A B
CC
A B A B A B
A B A B A
A B A B A
BC
mk
k
m
mF mg
x L
xv x
v a
m k
mx kx F t t
k m
k m A c B c A k m B F
k m c
G E F
k m c
F
C
k m c
F mA
F mA
C
k m c k m c
E ac F ak
v L mkc L
a