Whenever two Apollo astronauts were on the surface of the Moon, a third astronaut orbited the Moon. Assume the orbit to be circular and 323 km above the surface of the Moon, where the acceleration due to gravity is 1.20 m/s2. The radius of the Moon is 1.70×106 m. (a) Determine the astronaut's orbital speed. m/s (b) Determine the period of the orbit. s