
45Newtonian Mechanics
© 2010 Taylor & Francis Group, LLC
Example 2.6
A charged particle +e
1
moving with a very high velocity v
0
along a straight line passes another
charge +e
2
of mass m at a distance b. Assuming a central law of force of magnitude e
1
e
2
/r
2
between e
1
and e
2
, find the energy Q transferred from e
1
to e
2
during the encounter.
Solution:
Because the charged particle e
1
moves at a very high speed, we make the assumption that e
2
does
not have time to change position during the encounter, so we place e
2
on the x-axis at a distance
b from the origin (Figure 2.10). Let us now consider the impulse. From symmetry, we see that the
y component ...