From: utzoo!dciem!mmt Newsgroups: net.physics Title: Re: strategy in rainstorms - (nf) Article-I.D.: dciem.161 Posted: Fri Jan 28 14:48:16 1983 Received: Fri Jan 28 16:59:14 1983 References: watarts.1646 You can imagine your body sweeping out a volume of space in the rainstorm. If you stay in the rain for a time T, you will sweep out ATv cubic whatevers (A is the area you present to the rain, v the velocity you have relative to the rain) and all the rain in this volume will hit you. If you stay in the rain for a fixed time, it is best to stand still, or at least move at the speed of the wind, so that v is only the vertical velocity of the rain and A consists of your head and shoulders. If you need to go a certain distance, and do it very fast, Tv is essentially independent of your running speed, since v is dominated by your speed. But as your speed increases, so does A, the area you present to the rain (unless you lean very far forward, so that you still present your head and shoulders to the rain -- ie lean exactly as much as the perceived slant of the rain). At intermediate speeds, v includes components from both your velocity and that of the rain. Best to take an umbrella. I haven't worked it out, but there may be an optimum running rate for any particular trip in the rain. Maybe fastest is best if you can do it on your stomach. Martin Taylor