1. The problem statement, all variables and given/known data The earth has a radius of approximately 6400 km. If an object could orbit the earth just at its surface, how fast would it have to travel? 2. Relevant equations C = 2πr; ac=v2/r; Fc=mv2/r 3. The attempt at a solution Circumference = 12800π. I tried to solve for the rate by d = r x t (86400s = 24 hours) but my answer is very small.