why does a smaller ball rolling faster than a bigger ball

Question

What factors would cause a smaller object to roll farther than a larger one?

Answer 1

There are cases where a larger ball can travel faster than a smaller ball. However, consider the case where  both balls are under the same conditions (same mass, and placed at the same height on the same inclined plane, and assume negligible air resistance), then the smaller ball will travel faster than the larger ball. This is because the larger ball has a greater rotational inertia (I = 0.4mr² ) due to its larger radius. Because of its greater rotational inertia, the larger ball has a greater rotational kinetic energy 0.5 Iω², and hence a smaller translational kinetic energy 0.5mv². This means that the larger ball has a smaller speed.

Answer 2

A smaller ball has less surface area.  Therefore, it overcomes less friction of the surface it is in contact of.  Also, the smaller ball could have less mass.  This means less weight on the ball.