Two balls have the same size and mass. One is hollow, the other one is solid. How would you determine which is which without breaking them apart?

1 answer

same density.

Ok, roll them down a slight incline. They will have different moments of inertia, so the hollow one will have more inertia,so it will lag behind the solid ball.

http://hyperphysics.phy-astr.gsu.edu/hbase/imgmec/mic.gif