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

Radius (pencil), r1 = mm = 0.35 cm

Radius (graphite), r2 = mm = 0.05 cm

Height (Pencil), h = 14 cm

Volume of wood in pencil = π (r1² – r2²) h

= [(0.35)² – (0.05)² * 14]

= (0.1225 – 0.0025) * 14

= 44 * 0.12

= 5.28 cm³

Volume of graphite = πr2²h

= * (0.05)² * 14

= 44 * 0.0025

= 0.11 cm³