Question

A tiny object carrying charge of +3 micro Coulombs and a second tiny charged object are initially very far apart. if it takes 29.0 J of work to bring them to a final configuration in which the +3 micro Coulomb object is at x=1.00mm,y=1.00mm and the other charged object is at x=1.00mm,y=3.00mm, find the magnitude of charge on the second object. (k = 8.99 x 10^9 N m^2/C^2

Answer 1

from Coulumbs Law \[F = \frac{k \ q_1 q_2 }{r^2}\]
you can establish by integration the potential energy U of this system as the work done W to bring the particles together \[W = U = \frac{k \ q_1 q_2 }{r}\] the second charge must also be positive if work is required to bring them together, and the question requires you to assume that the energy of the system is initially zero.