Question

 Two small spheres, each carrying a net positive charge, are separated by 0.400 m. You have been asked to perform measurements that will allow you to determine the charge on each sphere. You set up a coordinate system with one sphere (charge 1) at the origin and the other sphere (charge q2) at x = +0.400 m. Available to you are a third sphere with net charge q3 = 3.00x10^-6 C and an apparatus that can accurately measure the location of this sphere and the net force on it. First you place the third sphere on the x-axis at x= 0.200 m; you measure the net force on it to be 5.50 N in the x-direction. Then you move the third sphere to x = +0.600 m and measure the net force on it now to be 3.50 N in the +x-direction.

 Part A

 Calculate q1.

 Part B

 Calculate q2.

Answer 1

......................(I)

.......................(II)

Solving (I) and (II), we get

Answer 2

When placed at x=0.2m, then the net force is

where

When placed at x=0.6m, then the net force is

Simply solve the 2 equations. Add them first,

and