Final answer:
The commutator is the part of the motor that causes the motion.
Step-by-step explanation:
In a motor, the motion is caused by the commutator. The commutator is a part of the motor that consists of a rotating cylinder with metal bars and brushes. When the electromagnet turns, the commutator changes the direction of the electrical current flowing through the electromagnet, causing it to rotate in the same direction consistently.
Learn more about Motor motion