Ask the Physicist!
Note: The Physicist is on vacation for a couple of weeks and answers will be coming less promptly than usual!
Do you have a question related to physics? Since 1999 I have answered more than 4000 questions on line and many more by brief email. To see how I select questions to answer, link here. If you do not submit a valid email address, I will not answer your question; if you do not receive an immediate automatic reply to your question, your email address was not valid or your mail server rejected the message. Please read the groundrules for the site. If the answer is to your liking, please consider making a donation to help support this service. A history of past questions and answers may be seen by clicking here. I have organized old answers into categories for easier searching or perusing.
There is now an Ask the Physicist facebook page. I cannot answer questions there because the formatting is too limited, but I will use the page to note recent answers which I find particularly interesting. If you "like" the page you will receive such notifications. Also, if you would like to make comments on my answers, that would be a good place.
Please read site groundrules and peruse the FAQ page before submitting your question. You can also search the site for previous answers. Although I do not answer homework questions or do tutoring, many of the sites which advertise on this site (look left) do.