An asteroid revolves around the Sun with a perihelion 0.5 AU and an aphelion of 7.5 AU. What is its period of revolution?
A) 4 years
B) 8 years
C) 16 years
D) 32 years
E) 64 years

Question

Quizplus · Accepted Answer

We can use Kepler's Third Law to calculate the period of revolution:
(T^2)/(a^3) = 1, where T is the period in years and a is the semi-major axis of the asteroid's orbit in astronomical units (AU).
The semi-major axis is the average of the perihelion and aphelion distances:
a = (0.5 AU + 7.5 AU)/2 = 4 AU
Plugging in the values, we get:
(T^2)/(4^3) = 1
T^2 = 64
T = 8 years
Therefore, the period of revolution is 8 years, which is choice B.

An Asteroid Revolves Around the Sun with a Perihelion 0