KILOPOUNDS

[Frank Buczek (santa Rosa Biomechanics Lab)]

Let me begin by thanking Tyler Amel for his thoughtful response to
Steve Wood's question about the term "kp." Please consider the
following as an alternative:

Because I remembered this unit more in association with the English
System rather than the International System of measures, I checked one
of my old mechanical design texts (MECHANICAL ENGINEERING DESIGN, J.E.
Shigley, 1977, p.17). Here, the term "kilopound" is discussed, and is
abbreviated "kip." This is considered a convenient form of
representing 1000 lbf (pounds force), NOT 1 kg x 9.81 m/s/s (what
Tyler has called one kg-force). I thought the distinction would be
important for at least two reasons: (1) practically speaking, any
conversion would be numerically incorrect when used with kilograms
rather than pounds-force, and perhaps more importantly, (2) a kilogram
(kg) is a measure of MASS not FORCE. Only when this mass is
accelerated at 1 m/s/s do we say there was an applied force of one
newton. I suspect Tyler already knows this, but in my opinion, his
explanation seems to cloud an issue we seem to come across all too
often in biomechanics.

Best Regards,
Frank

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Frank L. Buczek, Jr., Ph.D. (210) 705-6597 voice
Director, Biomechanics Laboratory (210) 705-6567 fax
Santa Rosa Outpatient Rehabilitation Center fbuczek@srhcc.org
for Children and Adults
2701 Babcock Road, San Antonio, Texas, 78229, USA
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