Re: my question will not fit in this space, please see below

Dear Nancy,
      Look in a geometry or elementary analysis text or engineering manual 
for the volume of a sphere.

          V = 4/3* pi * r^3  where pi ~ 3.14 and r^3 = r times r times r, 
the radius cubed and * means multiplication.

     In your case, the radius = 500 m. Grab that scientific calculator and 
type in

(4/3)*3.14*(500^3) = and you've got the number of cubic meters of volume of 
the original planet-buster.

    Now calculate the volume of a 1 meter diameter asteroid fragment with 
the same formula. Let's see: If the diameter is 1 then the radius = 0.5, so

     (4/3)*3.14*(0.5^3) = the number of cubic meters in each fragment. 

     Divide the volume of the original asteroid by the volume of a 
fragment and QED (which is Latin for quod erat demonstrandum), or "it has been 
solved"!
     Run your calculations and email your results to me at 
alrai@ix.netcom.com for verification. This is participatory science!
Yours truly,
Jim Foerch
James C. Veen Observatory