posted by Nic .
Comet Halley returns every 74 years. Find the average distance of the comet from the sun.
How do i do this??
Kepler's third law
For bodies in orbit around the same central body (like sun)
periods proportional to orbital major axis length ^3/2
74/1 = (RHalleyorbit/Rearthorbit)^1.5
Rearthorbit = 1.49 *10^11 meters