1. The problem statement, all variables and given/known data A certain spherical planet which is not rotating has a radius of 6.36 x 105 m and a mass of 1.89 x 1021 kg. At what minimum speed would a vehicle traveling along its surface just begin to leave the ground? 2. Relevant equations FC = mv2/r FG = GMm/d 3. The attempt at a solution My problem is I don't know how to set the initial equation up: Is it, FC = GMm/d2 = mv2/d Or is it, 1/2mv2 = GMm/d? They will differ by a factor of root 2. If it was vertical velocity I would know it needs to be KE = PE, but since it's horizontal I'm confused. Can someone explain?