I got the answer for
m is something that we deal with each day (even if we don't know about it) - it is more or less radius of atoms world around us is built of. Wave of this length must be easily observable in the world of atoms, and if so, you can be sure some physics/chemistry of the world surrounding us will be based on the interactions of the atoms and electrons travelling with that wavelength.
On the other hand, wavelength you calculated for the tennis ball is so short we wouldn't be able to observe it using none of the known physical effects (actually it is quite close to the so called Planck length, which some assume is the lowest possible measurable distance). As such it can safely ignored, it won't have any effect on anything.