a 1000 foot spool of bare 12-gauge copper wire weighs 19.8 pounds. How much will 18 inches of the wire weigh, in ounces?

0.4752 oz.

Explanation:

Length = 1000 ft

Converting ft to inches,

12 in = 1 ft

1000 ft = 1000 * 12

= 12000 in

0.05082 in = 0.12908 cm

Mass = 19.8 lb

Converting lb to oz,

1 ounce = 0.0625 lb

1 lb = 1/0.0625 oz

19.8 lb = 1/0.0625 * 19.8

= 316.8 ounce

Since, 12000 in of copper wire weighs 316.8 ounces.

Therefore, 1 in will weigh = 316.8/12000

= 0.0264 oz

18 in = 0.0264 * 18

= 0.4752 oz.