How Far Is Halley's Comet from the Sun?

[xArashix]

1. Comet Halley's comet returns every 74 years. Find the average distance of the comet from the sun?
2. I'm guessing Kepler's 3rd law...

The Attempt at a Solution

P_years^2= R_AU^3...i keep thinking that's wrong.

 

[berkeman]

1. Comet Halley's comet returns every 74 years. Find the average distance of the comet from the sun?



2. I'm guessing Kepler's 3rd law...

The Attempt at a Solution

P_years^2= R_AU^3...i keep thinking that's wrong.

Welcome to the PF.

What is the mass of the sun? What is the mass of Halley's comet? What is the equation for the gravitational force between two masses? What is the equation for the angular frequency in uniform circular motion?