Question

An iron ball 4 inches in diameter weighs 9 pounds. Find the Weight of an iron shell 2 inches thick whose external diameter is 20 inches.

Answer 1

First you need to find how much one cubic centimeter of iron weighs

Answer 2

So you would set it up like\[\frac{ 4\pi(2)^2 }{ 9}\]

Answer 3

to find lb/cubic inches

Answer 4

and then the iron shell is a hemi sphere

Answer 5

can you explain it step by step? I don't seem to get it. :/

Answer 6

\[\frac{ area~of~sphere }{ weight~of~sphere }= Pounds~per~cubic~inch\]

Answer 7

\[2\pi(2)^2=Cubic~inches~inside~of~hemisphere\]

Answer 8

\[Pounds~per~cubic~inch*area~of~hemisphere=weight~of~hemisphere\]

Answer 9

is it area or volume of the sphere? -.-