Given that
q = 9.6 μC
Q = + 66 μC and - 66 μC
r1 = 0.61 m, r2 = 0.82 m and 0.4 m
a) change in KE = qV = kqQ ( 1 / r1 - 1/r2)
                        =
9 x 109 * 9.6 x 10-6 * 66 x 10-6(
1 / 0.0.61 - 1 / 0.0.82)
                        =
2.39 J
b)change in KE = qV
                        =
kqQ ( 1 / r1 - 1/r2)
                        =
9 x 109 * 9.6 x 10-6 * -66 x10-6 (
1 / 0.61 - 1 / 0.4)
                        =
4.907 J
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