Question 3 (7 marks) Figure 2 shows a schematic diagram of a simple DC motor. A current is flowing through the coil and the motor is turning in the direction shown. rotation direction of the coil N split ring commutator DC battery terminal A terminal B Figure 2 a. Write '+' for positive and '-' for negative in the boxes above to indicate which terminal is positive and which is negative. 1 mark b. Using physics principles, justify your answer to part a. 3 marks C. The split-ring commutator consists of two copper rings that are separated by a split. Explain how this design enables the split-ring commutator to serve its purpose. 3 marks