- #1

Sarak

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## Homework Statement

The starter motor in an automobile has a resistance of 0.37 Ω in its armature windings. The motor operates on 12 V and has a back emf of 10 V when running at normal operating speed.

A)How much current does the motor draw at its operating speed?

**B)How much current does the motor draw when running at half its final rotational speed?**

## Homework Equations

Eb=V-IR

## The Attempt at a Solution

I found part A) to be 5.4 A. Our professor told of to divide this by two to get part B. Mastering Physics tells me that 2.7 A is a wrong answer. Is this a MP glitch or do I have the wrong info?