Two electrons repel each other with a force that varies inversely as the
square of the distance between them. If one electron is fixed at the point
(2, 4), find the work done in moving a second electron from (-2, 4) to
I said, F = k/d^2 = k/4^2, since the horizontal distance between the electrons is 4 units.
Then, I figured that the incremental Work, delta W = F(x)(delta x) =
(k/d^2)(3) since the second electron is moved 3 units to the right.
Therefore, W = Integral (from -2 to 1) of 3k/16 dx is what I determined the integral to be, which gives 3k/16[x] evaluated from -2 to 1 which gives 9k/16. However, this is wrong, the answer is 3k/4. Help??