Dont blame me if i am wrong, because i'm only 14, but i think that is the question of the vary vary small surface that your sphere is hitting. I mean that the presure is too big because of this law :

preasure = force/surface area
If you understand that the surface is vary small lets say 0.00001;
It is not vary important how strong is the force of the sphere when it's devided by a 0.0000001 it becomes 10000000 greater and the sphere gets pushed away with that amount of force according to 3th Newton law;