Question

1.Three identical conducting spheres initially have the following charges: sphere A, 4Q; sphere B, −6Q; and sphere C, 0. Spheres A and B are fixed in place, with a center-to- center separation that is much larger than the spheres. Two experiments are conducted. In experiment 1, sphere C is touched to sphere A and then (separately) to sphere B, and then it is removed. In experiment 2, starting with the same initial states, the procedure is reversed: Sphere C is touched to sphere B and then (separately) to sphere A, and then it is removed. What is the ratio of the electrostatic force between A and B at the end of experiment 2 to that at the end of experiment 1?

2.A charge, −q, is placed on the positive x-axis a distance d from the origin (x = d,y = 0). A second charge, +2q, is placed on the y-axis at (x = 0,y = h). Find the force on the +2q charge due to the −q charge. (Don’t forget that your final answer should be a vector and should be represented only in terms of variables given in the problem statement or known constants.)

Answer 1

here

the identical charges always share the total charge equally

C to A . A becomes 2Q ; C becomes 2Q

C to B . B becomes –2.5Q ; C becomes –2.5 Q

Force between A and B is attraction proportional to 2*2.5 = 5

C to B . B becomes –3 Q ; C becomes –3 Q

C to A . A becomes –3.5 Q ; C becomes –3.5 Q

Force between A and B is repulsion proportional to 3.5 * 3 = – 10.5