A book taken from Chapter 37 "Relativity" from the book 'University Physics with Modern Physics with Mastering Physics' (11th Edition) by Hugh D. Young and Roger A. Freedman
Hugh David Young was an American physicist who taught physics for 52 years at Carnegie Mellon University. Young is best known for co-authoring the later editions of University Physics, a highly regarded introductory physics textbook, with Francis Weston Sears and Mark W. Zemansky (this book — first published in 1949 — is often referred to as "Sears and Zemansky", although Hugh Young became a coauthor in 1973).