Solve the all parts of given problem:
Problem: The starter motor in an automobile has a resistance of 0.40 ohm in its armature windings. The motor operates on 12 V and has a back emf of 10 V when running at normal operating speed.
Part I: How much current does the motor draw when running at its operating speed?
Part II: How much current does the motor draw when running at half its final rotational speed?
Part III: How much current does the motor draw when starting up?
Show all work, use additional paper if necessary.