Question

A point charge with charge q1 = 4.00 μC is held stationary at the origin. A second point charge with charge q2 = -4.50 μC moves from the point ( 0.125 m , 0) to the point ( 0.290 m , 0.235 m ). How much work W is done by the electric force on the moving point charge?

Answer 1

Solution:

given: A point charge with charge q1 = 4.00 μC is held stationary at the origin

>A second point charge with charge q2 = -4.50 μC moves from the point ( 0.125 m , 0) to the point ( 0.290 m , 0.235 m )

To find out:How much work W is done by the electric force on the moving point charge?

Now:

W = kqQ (1/r1 -1/r2)
r1 = 0.125
The radial distance of the point (0.290 m, 0.235 m).from the origin is
r2 = √ (0.290 ^2 +0.235^2) = 0.373m

W = -9e9*4.5*4*1e-12 *(1/0.125 - 1/0.373) = -0.961 J

Minus shows work is done by the field.