Chapter 22, Problem 6P

This afternoon, you have a physics symposium class, and you are the presenter. You will be presenting a topic to physics majors and faculty. You have been so busy that you have not had time to prepare and you don’t even have an idea for a topic. You are frantically reading your physics textbook looking for an idea. In your reading, you have learned that the Earth carries a charge on its surface of about 10⁵ C, which results in electric fields in the atmosphere. This gets you very excited about a new theory. Suppose the Moon also carries a charge on the order of 10⁵ C, with the opposite sign! Maybe the orbit of the Moon around the Earth is due to electrical attraction between the Moon and the Earth! There’s an idea for your symposium presentation! You quickly jot down a few notes and run off to your symposium. While you are speaking, you notice one of the professors doing some calculations on a scrap of paper. Uh-oh! He has just raised his hand with a question. Why are you embarrassed?