Mc. Auric Goldfinger, criminal mastermind, intends to smuggle several tons of gold across international borders disgulsing it as lumps of firon ore. He commands his engineer minions to form the gold into little spheres with a diameter of exactly 8cm and paint them black. Howevet, his chief engineer points out that customs ofnclals will surely notice the unusual weight of the "iron ore" if the balls are made of solid gold (density 19.3g/cm3 ). He suggests forming the gold into hollow balls intead (see sketch at right), so that the faike "iron ore" has the same density as real iron ore (5.15g/cm3). Calculate the required thickness of the walts of each hollow lump of "iron ore." Be sure your answer has a unit syr