This preview shows page 1. Sign up to view the full content.
45. (a) The potential energy is
U
=
q
2
4
πε
0
d
=
(8
.
99
×
10
9
N
·
m
2
/
C
2
)(5
.
0
×
10
−
6
C)
2
1
.
00 m
=0
.
225 J
relative to the potential energy at infnite separation.
(b) Each sphere repels the other with a Force that has magnitude
F
=
q
2
4
πε
0
d
2
=
(8
.
99
×
10
9
N
·
m
2
/
C
2
)(5
.
0
×
10
−
6
C)
2
(1
.
00 m)
2
=0
.
225 N
.
According to Newton’s second law the acceleration oF each sphere is the Force divided by the mass
oF the sphere. Let
m
A
and
m
B
be the masses oF the spheres. The acceleration oF sphere
A
is
a
A
=
F
m
A
=
0
.
225 N
5
.
0
×
10
−
3
kg
=45
.
0m
/
s
2
and the acceleration oF sphere
B
is
a
B
=
F
m
B
=
0
.
225 N
10
×
10
−
3
kg
=22
.
5m
/
s
2
.
(c) Energy is conserved. The initial potential energy is
U
=0
.
225 J, as calculated in part (a). The
initial kinetic energy is zero since the spheres start From rest. The fnal potential energy is zero
since the spheres are then Far apart. The fnal kinetic energy is
1
2
m
A
v
2
A
+
This is the end of the preview. Sign up
to
access the rest of the document.
This note was uploaded on 11/12/2011 for the course PHYS 2001 taught by Professor Sprunger during the Fall '08 term at LSU.
 Fall '08
 SPRUNGER
 Physics, Energy, Force, Potential Energy

Click to edit the document details