Jornal de Física
(r )
!
#$
& !
!
"
!
%%
(∆r )
'
(
r fin − rin
&
∆r
"
)
'
*
+
)
,
/.
*
0
*!
*
.
)
!
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*
)
1
/
!
(vm )
vm =
∆r
∆t
.
rin
0
∆r ≤ ∆S
∆t
.
r fin
*
.
-
*
*
∆r
* ∆r
∆t
.
2/
(am )
&
am =
*
!
∆v
∆t
am
3
/
∆v
&
!
2
)
*
1
.
5
7
*
+
4
*
&
1
8% 9
1
+
:;
*
*) (
*
4
6
*
!
(
! *2
*
/
(/
&
-
!*
!
:
&
:*
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<
*
4
*
*
*
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)
;1
=
+
(
3
8% 9
1
+
+
+
/
1
*
!
4
> /
!
+
!
1
&
a R = at + acp
a R2 = at2 + acp2
*
5
*
> /