Three identical ceiling fans behave as follows:
• Fan A makes 60 revolutions every minute at steady speed.
• Fan B makes 90 revolutions every minute at steady speed.
• Fan C speeds up and slows down irregularly, averaging about 60 revolutions per minute.
a. Arrange Fan A and Fan B in ascending order of their time period.
b. Which of the three fans exhibit uniform circular motion? Give a brief reason for your answer.