.4
.
x dx u dt du acm dt F m F
F
I I
m
P ewton
d dt d dt
m u
F
dP dt
0,
P
L I
.
.
W
=f(t) =f(t) =f(t)
.
1 2
K
1
1
m u2 2 2
.
W=
m u2
1
L=
0,
W=F x K
ewton
dL dt
m u2 1 2
W
2
1 2 I
I
2
2 2
1
x=ut t 1 2 x=x0+u0t ± t 2 t =u0 CM S =uo2/2
2
I
2 1
=f(t)
t
u=u0
0t
0
t
=f(t)
·t
0
±
.
1 2
t2
=f(t)
0/ 2 o /2
1