A lead pencil consists of a cylinder of wood with a solid cylinder of graphite filled in the interior. The diameter of the pencil is 7 mm and the diameter of the graphite is 1 mm. If the length of the pencil is 14 cm, find the volume of the wood and that of the graphite.

Explanation

Volume of graphite=`pir^2h`

=`22/7*(1/4)^2 140`

=`110mm^2`

Total volume=`piR^2h`

=`22/7*(7/2)^2*140`

=`5390mm^2`

Volume of wood=total volume-volume of sphere

=`5340-110mm^3`

...