# Asteroid in a circular orbit about the Sun

If the Earth's period is 365.25 days and its distance to the (center of the) Sun is one astronomical unit (AU), what is the period, to the nearest day, of an asteroid in a circular orbit about the Sun with a radius of 3.04 AU?

please show steps so that I can learn.

thanks a lot.

## Answers and Replies

rock.freak667
Homework Helper
What are the relevant equations that you think are needed here?
Newton's law of gravitation maybe?

I think the equation for the period of a planet is needed; but i'm not sure how to use it.

Kepler's equation relating period to radius.
If this isn't given, it can be derived by equating the equation for centripetal force to the equation for universal gravitational force.