Chapter 21, Problem 71P

In a spherical metal shell of radius R, an electron is shot from the center directly toward a tiny hole in the shell, through which it escapes. The shell is negatively charged with a surface charge density (charge per unit area) of 6.90 × 10⁻¹³ C/m². What is the magnitude of the electron’s acceleration when it reaches radial distances (a) r = 0.500R and (b) 2.00R?