[填空题]
The asteroid belt between Mars and Jupiter coft 96s0;llnumh0 a;fznsists of manyntt)s),z.i ls fragments (which some space scientists think came from a planet that once orbited the Sun but was dess.,)zitl nts )troyed).
(a) If the center of mass of the asteroid belt (where the planet would have been) is about three times farther from the Sun than the Earth is, how long would it have taken this hypothetical planet to orbit the Sun?$\approx$ y
(b) Can we use these data to deduce the mass of this planet?
