Question

To solve a problem using the equation for Kepler’s third law, Enrico must convert the average distance of Mars from the Sun from meters into astronomical units.

How should he make the conversion?

multiply the average distance by 1.5 × 1011
multiply 1.5 × 1011 by the average distance
divide the average distance by 1.5 × 1011
divide 1.5 × 1011 by the average distance

Answer 1

By definition, 1 astronomical unit (AU) is the distance from the Earth to the Sun, and this is equivalent to around 150,000,000 km, or 1.5 x 10^8 km. This is also equivalent to 1.5 x 10^11 meters. Therefore, if we are given the distance in meters, we have to divide by 1.5 x 10^11 to convert to AU. This is the third choice.