Problema Solution
The weight of a metal sphere 8 inches in diameter is 6 lbs. what is the weight of a shell 3 inches thick whose diameter is 16 inches if it is made of the same metal.
Answer provided by our tutors
we know that denity=weight/volume
volume of 8inch sphere=(4/3)*pi*r3 = (4/3)*3.14*(8/2)3=268.08
density=6lbs/268.08 inch3
now, if the outer diameter of the shell is 16 inches then the
inner diameter will be 16-3=13 inches
volume of shell=(4/3)*pi*(16/2)3-(4/3)*pi*(13/2)3=994.31 cubic inches
weight of shell=volume * density = 994.31 *6/268.08 = 22.25 lbs