1. A nonconducting spherical shell, with an inner radius of R1 and an outer radius of R2, has positive charge spread nonuniformly through its volume between its inner and outer surfaces. The volume charge density (r) is the charge per unit volume, within this shell =br², where r is the distance from the center of the shell and b is a constant.

a) What is the net charge in the shell?

b) If a charge Q with mass m is shot toward the charged sphere with an initial speed v0 a distance 4R2 from the center of the charged sphere and instantaneously comes to rest just as it reaches the surface of the charged shell, determine what the initial speed v0 would need to be in terms of k, Q, m, b, R1, R2

2. Consider a particle with positive charge Q located on the y-axis a distance a from the origin and a second particle with positive charge q located along the x-axis a distance d from the origin. What's the value of d for which the x component of the force on the second particle is the greatest?