A copper refinery produces a copper ingot weighing 150 lb. If the copper is drawn into wire whose diameter is 8.25 mm, how many feet of copper can be obtained from the ingot? The density of copper is 8.94 g/cm^3 (Assume that the wire is a cylinder whose volume is V = pir^2h, where r is its radius and h is its height or length.)
Edited: 150lb x 454g/lb = 68,100g of copper. Radius = (8.25mm / 10mm/cm) / 2 = 0.4125cm. Cross section area = π x r? = 3.142 x 0.4125 x 0.4125 = 0.535cm?. 0.535cm? x 8.94g/cm? = 0.4273g/cm length. 68,100g / 0.4273g/cm = 159.14cm. 159.14cm / 30.48cm/foot = 5,221 feet of copper wire. (Check: (159.14cm x 0.4273g/cm length) / 30.48cm/ft. = 68,000g / 454g/lb = 149.8lbs).
