On July 19, 1969, the lunar orbit of Apollo 11 was adjusted to an average height of 159 kilometers above the Moon's surface. The radius of the Moon is 1720 kilometers, and the mass of the Moon is 7.3 x 1022 kilograms.a. At what speed did the spacecraft orbit the Moon? Include units in your answer. b. How long did it take to orbit once? Include units in your answer. But just for perspective, note that one hour is 3600 s.