1. The problem statement, all variables and given/known data Which would be faster: A ball rolling down a ramp with no groove, or a ball rolling down a ramp with a groove? What effect does the radius have, if any? Disregarding resistance and whether or not the ball rolls in a straight line. 2. Relevant equations 3. The attempt at a solution I thought that a decrease in rolling radius due to being in the groove might have an effect but apparently not. Any input appreciated.