Question

You're writing the instruction manual for a power saw, and you have to specify the maximum permissible length for an extension cord made from 18-gauge copper wire (diameter 1.0 mm). The saw draws 6.0 A and needs a minimum of 115 V across its motor when the outlet supplies 120 V. What do you specify for the maximum length of the extension cord, given that they come in 25-foot increments? (answers of 75, 125, 130, 150, and 300ft are all incorrect)...

Answer 1

That's fine: 19 meters is 62.4 feet

SO THE LONGEST USABLE EXTENSION CORD WOULD BE THE 50 FOOT CORD!

Answer 2

The voltage drop across the wire is, V=120V-115V The resistance of the wire is, 5 V 6.0 A -0.833 2 The expression of the resistance is, 0.833 Ω= (1.68x10" Ω·m) 1.0x10-3 m 1.0x 10-3 m2 (0.833 Ω)| π 1.68x10-8 Q.m - 38.92 nm The length should be half. 38.92 m 19.46 m -63.9 ft The answer is 50ft