1. The problem statement, all variables and given/known data An object orbits the earth at a constant speed in a circle of radius 6.38x10^6m, very close to but not touching the earth's surface. What is its centripetal acceleraion? 2. Relevant equations 3. The attempt at a solution Quick question, when would GM/r^2 equal to the centripetal acceleration, and when wouldn't it? I thought it always did but some calculations don't have the same numbers if you do it both ways. For this question would it be?