Sphere versus Cylinder
Would a cylinder or a sphere win a race down the ramp?
What difference does the shape make in our equation? The difference comes in the KE for rotations in the moment of inertia, I. For a sphere (ball), I = (2/5)mr2, while for a cylinder it would be I=(1/2)mr2. This ultimately changes the (10/7) factor into (4/3), the value from 2.65 m/s to 2.55 m/s.