Hrvoje Niksic wrote: > It would be possible for US pound to only refer to weight, but I > cannot find references to corroborate it. For example, taken from > Wikipedia: > > In 1958 the United States and countries of the Commonwealth of > Nations agreed upon common definitions for the pound and the > yard. The international avoirdupois pound was defined as exactly > 453.59237 grams. > > The "pound-force" wikipedia entry documents "pound" being used as a > unit of force "in some contexts, such as structural engineering > applications."
Then there's the even more fun and games in contexts where a distinction between mass and weight is not bothered to be drawn at all. It's more common in practical engineering matters than pure physics; this is, for instance, why rocket motor performance (specific impulse) is measured in seconds, as it's the ratio of the the thrust (force) to rate of fuel usage (would be mass divided by time, but weight on Earth is used instead of mass). Basically, physics rationalizations of Imperial/English/American (whatever you choose to call them) units are a total mess. -- Erik Max Francis && [EMAIL PROTECTED] && http://www.alcyone.com/max/ San Jose, CA, USA && 37 18 N 121 57 W && AIM, Y!M erikmaxfrancis Man has wrested from nature the power to make the world a desert or to make deserts bloom. -- Adlai Stevenson, 1952 -- http://mail.python.org/mailman/listinfo/python-list
