Two ball bearings, each with 16 balls, are used to support the shaft of a fan that rotates at \(750 \mathrm{rpm}\). Determine the frequencies, in hertz, corresponding to the following defects: * cage, inner race, outer race, and ball. Assume that \(d=15 \mathrm{~mm}, D=100 \mathrm{~mm}\), and \(\alpha=30^{\circ}\).