posted by Kristen .
Whenever two Apollo astronauts were on the surface of the Moon, a third astronaut orbited the Moon. Assume the orbit to be circular and 160 km above the surface of the Moon, where the acceleration due to gravity is 1.42 m/s2. The radius of the Moon is 1.70 106 m.
(a) Determine the astronaut's orbital speed.
(b) Determine the period of the orbit.
I know I should use the variation of Newton's second law that says F=ma, or F=m(v^2/r). I just don't really get how to relate these two problems, since I have a radius of the moon, and a radius of orbit.
a)find r : 160*10^3 + 1.7*10^6 = ...
V=sqrt(ar)= sqrt(1.42r)= ... That's your answer.