Chapter 24, Problem 62P

You’re heading out for spring break, but your car won’t start. Your friend says you might have corrosion at the battery terminals—a frequent cause of hard starting because of increased resistance. Having read Example 24.4, you know that the resistance between battery and starter should be around 1 mΩ. While your friend cranks the starter, you measure 4.2 V between the battery terminal and the wire carrying current to the starter motor. If the motor draws 125 A, is the resistance in its normal range?