That's Entertainment!

xkcd: Physics for Entertainment

Physics for Entertainment was written by Yakov Perelman in the 1920ā€™s (in Russian) and updated periodically through the 1930ā€™s. There are actually two parts to it, but Volume 1 is long out-of-print (though findable online ā€” more on that later). The book I have is a 1975 translation of Volume 2. The book is a series of a few hundred examples, no more than one or two pages each, asking a question that illustrates some idea in basic physics.