A little high school lesson regarding Han's points:
I'm rather uncomfortable with the obfuscation and lax use of the terms "weight" and "mass."
A "pound" is not a unit of mass, it is a unit of weight, which is a specific form of force. In fact, force is mass multiplied by acceleration and in the case of a pound it would be 1 slug x 32 ft/s2.
The equivalent metric unit is the Newton, where one Newton equals one kilogram accelerated at 9.8 meters per second squared.
Without such basic concepts, nomenclature is pointless.
Robert would expect to get more butter in a pound in Denver than in Boston because thw acceleration due to gravity is less in Denver than in Boston. The British and the Canadian Weigths and Measures Acts both define the poound as a unit of mass, not a unit of weight. The aeronautical engineer's unit of mass is the slug = 32.2 pounds-mass. Victorian physicists solved the linguistic problem by recognizing the pound as a unit of mass but the poundal as a unit of force:
32.2 poundals = 1 pound-force
Physicists recognize Newton's First Law of Motion as
force (newtons) = mass (kilograms) X acceleration (metres/second^2)
Engineers have to say:
force (pounds) = mass (pounds) X acceleration (feet/second^2)/32.2When Canada went metrtic an elderly Professor of Mechanical Engineering at McMaster University, Hamilton, taught that under the metric system Newton's First Law was only true at a point in space where the acceleration due to gravity is 1 metre per seond squared. --
Joseph B. Reid
17 Glebe Road West
Toronto M5P 1C8 Telephone 416-486-6071
