I will try to answer one of your questions...
Mark Simon wrote:
The weather report predicts there will be a west wind with velocity of 28 km/h. I am going to ride my bicycle about 18 km towards the west today. I cannot visualize 28 km/h, but I can visualize 7.8 m/s. This means to me that I will get a better workout, going to my destination, and should have an easier ride home. Would somebody please explain the logic of measuring velocity in km/h?
There likely is no logic in reporting wind speeds in kilometers per hour, except that people are used to hour-based rates in these reports. Meteorologists actually measure wind speeds in meters per second.
Historically, sailors were the ones concerned with wind speeds because they accounted for windage in their dead reckoning. Those wind speeds were estimated in knots (nautical miles per hour), the units used for ship's speed. That practice of using hour-based wind speeds carried over into practice on shore in coast-predominant nations, I imagine, such as the UK, coastal Europe, and the fledgling U.S.
Jim I do not understand why this is
done. I live in Southern California, and traffic is unpredictable here. When I drive, I am only concerned with safety, and leave additional time to get to my destination. If were are going to convert to the metric system in the United States, why not consider using m/s as the basic unit? I am usually only concerned with my velocity when the traffic light turns yellow in front of me, and I have to make a decision whether to decelerate or continue driving. If my velocity is measured in m/s, that would make calculations simpler. In Europe, with its denser populations, does measuring velocity in km/h work well in calculations? I wager that highways are engineered using m/s calculations. Is it possible to get a velocimeter for a bicycle that measures in m/s?
-- James R. Frysinger 632 Stony Point Mountain Road Doyle, TN 38559-3030 (C) 931.212.0267 (H) 931.657.3107 (F) 931.657.3108
