A long non-conducting cylinder has a charge density p = a*r, where a = 4.73 C/m^4 and r is in meters, and a radius of 0.0437m . Concentric around it is a hollow metallic cylindrical shell with an inner radius of 0.119m and an outer radius of 0.158m. 1) What is the electric field at 0.172m from the central axis? Answer in units of N/C. 2) What is the surface charge density inside the hollow cylinder? Answer in units of C/m2. For part 1 I've already solved a few equations for charges at various radiuses along the inside of the cylinder, between the cylinder and the shell, etc, and I have the equation of (a*r^3)/(3*R*ε0), but I know this won't work because the radius is now outside the shell. I know the shell has no net charge, conceptually, so the charge outside is negative... but I'm still not sure what my R is for this equation. For the second part I'm almost totally lost. The E = ([tex]/sigma[/tex])/ε0) doesn't make sense to me unless I'm supposed to get E for the radius JUST inside of the shell and use that.