Problem 28.

A point charge is held stationary at the origin. A second point charge is moves from the point x = 0.20 m, y = 0 to the point x = 0.3 m, y = 0.35 m. How much work is done by the electric force on ?

Solution

The work done by electric force on the second charge is equal to (minus) change of the electric potential energy of the charge in the field of charge .

The initial distance between the charges is

The final distance is

Then