A helium nucleus (m = 6.64 1027 kg, net charge q = 2e) is fired directly toward a spherical conductor on a radially in- ward path. The conductor, which is fixed in place, has radius R = 0.25 m and surface charge density = 7.0 C/m2. If the helium nucleus is initially very far away from the conduc- tor, then what initial speed vi must it be given so that it just barely avoids touching the surface of the conductor before be- ing repelled back to infinity? For the limits check, investigate what happens to vi as the charge density approaches infinity