<PRE><B>Question 1174168</B>
The radius is 50 x 10^(-6) m, 5 x 10^(-5)m and the volume is (4/3)*π*125 x(10^-15)m^3
=523.6*10^(-15)m^3, or 5.236 x 10^(-13 )m^3
1 m^3/2550 kg =5.236 *10^-13/x; also, 2.55 x 10^3 kg= 2.55 x 10^6 gm
1 m* x=13.35 x 10^(-7) gm or 1.335 x (10^-6) gm., the mass of each grain.
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total surface area of one sand grain is 4*π*r^2=4π(25 x 10^-10)=3.142 x 10*(-8) m^2
surface area of a cube 1.2 m on an edge is 1.2*1.2*6=8.64 m^2
the number of grains would then be 8.64/3.142 x 10^-8
=2.75 x 10^8 grains.
each grain has 1.335 x 10^(-6) gm mass/grain, so the product would be 3.671 X 10^2 or 367 gm of sand.
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