In Praise of Simple Physics: The Science and Mathematics Behind Everyday Questions, by Paul J. Nahin, Princeton University Press, Princeton, New Jersey, 2016. 272 pp., $29.9 (hardbound). ISBN 978-0-691-16693-3.
Using the term “simple” in the title is very much a matter of perspective. While the topics will be of interest to the general reader, there is no dodging of the mathematics used to explain them. Each topic is introduced and then the equations are listed and analyzed until the solution is achieved. At times, the derivation takes up sufficient space. For example, in the chapter “How to Catch a Baseball (Or Not),” the topic is how a fielder will turn their back on a fly ball, run to the proper location and then turn around and catch it. The derivation of the solution is a series of equation equalities that runs for over three-quarters of a page.
While there is a bit of history and some background, the general tactic is to state the problem and then go right to the equations used to find the solution. Some of the topics are:
*) How to Measure Depth With a Stopwatch – dropping a rock in a hole and determining the depth by the elapsed time before hearing it reach the bottom.
*) Vectors and Bad Hair Days – selecting the proper angle to orient to the wind to avoid having your hair messed up.
*) Energy From Moving Air – a derivation of how much energy can be extracted from wind.
*) The Traffic Light Dilemma – trying to determine the decision procedure as to whether to speed up or stop when a traffic light turns yellow.
*) How Some Things Float (or Don’t) – an analysis of the problem as to whether the water level in a pond goes up or down if you throw something out of a boat.
The situations and their solutions are interesting independent of the mathematics. If the math were to be extracted and the scenarios with succinct solutions were to be in a much shorter book, people that do not understand the math would find that book to be well worth reading.
Instructors of physics or mathematics that are looking for problems to challenge and interest their students will find some valuable material in this book. All of the problems are easy to understand and the math is challenging. While a few of the problems can be solved using only algebra, more advanced mathematics such as trigonometry and calculus are needed to work through most of them.
This book was made available for free for review purposes.