A satellite in orbit around the earth has a period of one hour. An identical satellite is placed in an orbit having a radius that is nine times larger than that of the first satellite. What is the period of the second satellite?
A)0.04 h
B)3 h
C)4 h
D)9 h
E)27 h

Question

Quizplus · Accepted Answer

According to Kepler's third law, the square of the orbital period is proportional to the cube of the semi-major axis of its orbit. If the radius is increased by a factor of 9, the period increases by a factor of 9^(3/2) = 27. Thus, the period of the second satellite is 27 hours.

A Satellite in Orbit Around the Earth Has a Period