(adsbygoogle = window.adsbygoogle || []).push({}); Planet Orbits, finding radius HELPP!!

1. The problem statement, all variables and given/known data

The planet mars has a mass of 6.418*10^{23}kg and completes an orbit around the sun in 687 days. The sun has a mass of 1.99 * 10^{30}kg. what is the average radius of the orbit of mars?

2. Relevant equations

Force Gravity = G*(m^{1}m^{2})/r^{2}

Force Centripital = mv^{2}/r

G = 6.67 * 10^{-11}

3. The attempt at a solution

I tried plugging in the numbers into the Universal gravitaiton formula where m1 was the mass of mars * m2 which is the mass of the sun * Universal gravitation. I didn't know what to use as Force Gravity.

with the force centripital formula, you have 2 masses. how could i go about finding the velocity of mars if i dont have the radius??

thanks for the help

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# Homework Help: Planet Orbits, finding radius HELPP

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