Whenever two Apollo astronauts were on the surface of the Moon, a third astronaut orbited the Moon. Assume the orbit to be circular and 680 km above the surface of the Moon, where the acceleration due to gravity is 0.867 m/s2. The radius of the Moon is 1.70 x10^6 m.
(a) Determine the astronaut's orbital speed.
(b) Determine the period of the orbit.