A helium nucleus has radius rHe = 1.9 fm, mass m = 6.6 × 10-27 kg, and charge +2e. A gold nucleus has charge +87e and radius rAu = 7.0 fm. What initial speed must a helium nucleus have if it is to come into contact with a fixed gold nucleus in a head on collision? (Use the distance between the nuclei's centers of mass as the distance in your Coulomb force equation. What is the maximum distance between centers of mass when the atoms collide? This gives you the minimum initial speed needed for a collision.)