1. ## Planetary Motion

Kepler's Third Law of Planetary Motion states that the square of the period of revolution T of a planet varies directly with the cube of its mean distance a from the Sun. If the mean distance of Earth from the Sun is 93 million miles, what is the mean distance of the planet Mercury from the Sun, given that Mercury has a "year" of 88 days.

Is the correct formula T^2 = (a^3)k?

2. ## Re: Planetary Motion

Yes, and you can find the value of k from the orbit of the Earth, and then find a as it applies to Mercury.

3. ## Re: Planetary Motion

Originally Posted by MarkFL
Yes, and you can find the value of k from the orbit of the Earth, and then find a as it applies to Mercury.