College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 41

A man wishes to vacuum his car with a canister vacuum cleaner marked 535 W at 120 V. The car is parked far from the building, so he uses an extension cord 15.0 m long to plug the cleaner into a 120-V source. Assume the cleaner has constant resistance. (a) If the resistance of each of the two conductors of the extension cord is 0.900 V, what is the actual power delivered to the cleaner (b) If, instead, the power is to be at least 525 W, what must be the diameter of each of two identical copper conductors in the cord the young man buys (c) Repeat part (b) if the power is to be at least 532 W. Suggestion: A symbolic solution can simplify the calculations.