[填空题]
The rings of Saturn are lf0 ugxt* 11) ykyvs/k/5w*ziammsfl 57 kml*1 bs/ f;m 2ksnicomposed of chunks of ice that orbit the planet. The inner radius of the rings*/*si1a5lwmkm/sb7fn l2k im f;s 5mz is 73,000 $\mathrm{~km}$ , while the outer radius is 170,000$ \mathrm{~km}$ . Find the period of an orbiting chunk of ice at the inner radius and the period of a chunk at the outer radius. Compare your numbers with Saturn's mean rotation period of 10 hours and 39 minutes. The mass of Saturn is 5.7 $\times 10^{26} \mathrm{~kg}$ .
