Two similar coaxial coils of wire of radius 32.1 cm are directly on top of one other, separated by a 3.07 mm gap. The lower coil is on the flat table and consists of a current i in the clockwise direction; the upper coil carries a similar current and consists of a mass of 69.1 g. Find out the magnitude which the current in the upper coil has to have to keep the coil levitated at its present height.