A hollow cylindrical iron pipe with external and internal radii 8 cm and 6 cm respectively and length 35cm is melted and recast into a solid wire of thickness 2.8cm. Find the length of the wire
volume of iron is
π(8^2-6^2)*35 = 980π cm^3
when you say the wire has "thickness" 2.8cm, does that mean its diameter? If so, then it has length x where
1/4 π * 1.4^2 * x = 980π
x = 2000 cm