An astrophysicist sports nut explains why curve balls curve, why rackets and bats have ""sweet spots,"" how the javelin flies. Basketball, we hear, has been Brancazio's lifelong, spare-time passion. But it wasn't until a friend inquired ""if you're so smart, how come you stink at basketball?"" that he decided to combine his vocation and his avocation. The result is complicated and intriguing; it could also be of practical help to readers willing to figure out just what applies to their particular circumstances. Brancazio divides his subject according to the laws of physics (not by sport). Motion is explained first--in teres of velocity, acceleration, inertia, action and reaction. Runners, especially, can benefit. Brancazio then investigates other types of forces (gravity, torque, rotational action); energy (principles of work and power); collisions (karate adherents take note); motion through fluids; and resistance. Though he leads readers gently by the hand, this is still nota snap: ""if you understand, even in a nonmathematical way, the basic properties of and distinctions among speed, velocity, and acceleration, then you should have no difficulty with. . . a demonstration of the power and practical value of scientific analysis through an examination of the kinematics of running."" Along the way, lots of trivia questions are answered (e.g., why left-handed pitchers are called southpaws)--but some matters escape even Brancazio: ""how does the neophyte cliff-diver get to perfect his technique? Who was the first person to attempt this dive? What on earth possessed him to try it?"" Unusual and instructive: a departure with broad offbeat appeal.