[edimerz]

Ok, if it is ball bearings, then how we go ahead?

[P]

Estimate the dimentions of the bb  --  say 1 - 1.5 mm in diameter??    Work out the area 1 mole (6.02*10^23) of bbs would cover.  Divide this by area of the state to find out the number of layers of bbs you have  -  multiply by the diameter for the depth.

[edimerz]

This can be of help:
Search for BB in dictionary.com:

http://dictionary.reference.com/search?q=bb

[edimerz]

Sorry - but, ball bearings can be of different sizes (?), can  it be baseball (in general size is same).

[Borek]

Estimate the dimentions of the bb  --  say 1 - 1.5 mm in diameter??    Work out the area 1 mole (6.02*10^23) of bbs would cover.  Divide this by area of the state to find out the number of layers of bbs you have  -  multiply by the diameter for the depth.

Not so easy - distance between layers is not R (or 2r).

[P]

Not so easy - distance between layers is not R (or 2r).

Ahh...   I see where your coming from  -  are you suggesting they hexagonally close pack the layers on top of each other so that 3 layers for example would not equal to 3R!?   I think that this is fast becoming a maths/geometry question then!  the only chemistry really is the fact that 1 mole is 6.02 x 10^23.  I think I'm right in saying that you have to estimate the diameter of the bb though (otherwise the question is impossible)  - 

Sorry - but, ball bearings can be of different sizes (?), can it be baseball (in general size is same).

I certainly have never seen a baseball sized ball bearing. It would be quite heavy.

[edimerz]

I certainly have never seen a baseball sized ball bearing. It would be quite heavy.

Sure!

[Borek]

Ahh...   I see where your coming from  -  are you suggesting they hexagonally close pack the layers on top of each other so that 3 layers for example would not equal to 3R!?

Yep.