1. The problem statement, all variables and given/known data Mars orbits the sun at 1.52 Earth's orbital radius. What is the period of Mars in Earth years? 2. Relevant equations ΣFc = mac 3. The attempt at a solution I am unsure how to do this problem as this is the first "orbital period" question that I have encountered. Do I use the equation ΣFc = mac to solve this question, or is there another equation specifically for orbital periods that I don't know about? because if I go the ΣFc = mac route I get: ΣFc = mac Fg = m4(pie)^2r/T^2 GMem/r^2 = m4(pie)^2(1.52)r/T^2 GMe/r^2 = 4(pie)^2(1.52)r/T^2 (GMe)(T^2) = 4(pie)^2(1.52)r^3 T = √4(pie)^2(1.52)r^3/GMe This is my first orbital period question so I was just wondering would this be the correct way to solve it?